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- Front Matter: Volume 8453
- CCDs I
- UV Detection I
- Cryogenic Detectors
- CMOS Sensors
- CMOS and Hybrid X-Ray Detectors
- Focal Plane Arrays
- X-Ray Detectors I
- IR Detectors I
- IR Detectors II
- IR Detectors III
- Space Radiation Damage
- X-Ray Detectors II
- Testing
- Electronics/Readout
- CCDs II
- CCDs III
- IR Detectors IV
- Posters-Monday
Front Matter: Volume 8453
Front Matter: Volume 8453
Show abstract
This PDF file contains the front matter associated with SPIE Proceedings Volume 8000, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.
CCDs I
Photon counting EMCCDs: new opportunities for high time resolution astrophysics
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Electron Multiplying CCDs (EMCCDs) are used much less often than they might be because of the challenges they offer
camera designers more comfortable with the design of slow-scan detector systems. However they offer an entirely new
range of opportunities in astrophysical instrumentation. This paper will show some of the exciting new results obtained
with these remarkable devices and talk about their potential in other areas of astrophysical application. We will then
describe how they may be operated to give the very best performance at the lowest possible light levels. We will show
that clock induced charge may be reduced to negligible levels and that, with care, devices may be clocked at significantly
higher speeds than usually achieved. As an example of the advantages offered by these detectors we will show how a
multi-detector EMCCD curvature wavefront sensor will revolutionise the sensitivity of adaptive optics instruments and
been able to deliver the highest resolution images ever taken in the visible or the near infrared.
Characterization results of EMCCDs for extreme low-light imaging
Show abstract
EMCCDs are capable of extreme low light imaging thanks to sub-electron read-out noise, enabling single-photon counting.
The characterization of e2v's CCD60 (128 x 128), CCD97 (512 x 512) and CCD201-20 (1024 x 1024) using a controller
optimized for the driving of EMCCDs at a high (≥10 MHz) pixel rate per output with < 0.002 e- total background signal.
Using the CCD Controller for Counting Photons (CCCP), the horizontal and vertical CIC, dark current and EM gain
stability are characterized.
Charge-coupled devices for the ESA Euclid M-class Mission
Show abstract
The European Space Agency has funded e2v’s development of an image sensor for the visible instrument in the Euclid
space telescope. Euclid has been selected for a medium class mission launch opportunity in 2020. The project aims to
map the dark universe with two complementary methods; a galaxy red-shift survey and weak gravitational lensing using near infrared and visible instruments. The baseline for the visible instrument was to be the CCD203-82, which has been successfully flown on NASA’s Solar Dynamics Observatory. However, to optimise the device for Euclid, e2v have designed and manufactured the CCD273-84. This device has a higher-responsivity lower-noise amplifier, enhanced red response, parallel charge injection structures and narrower registers which improve low signal charge transfer efficiency. Development models for Euclid have been manufactured with a thinner gate dielectric than standard for improved tolerance to ionising radiation. This paper describes the imager sensor in detail and focuses on the novel aspects of the device, package and interface.
CCD research and development at Lawrence Berkeley National Laboratory
Show abstract
We describe work at Lawrence Berkeley National Laboratory (LBNL) to develop enhanced performance, fully
depleted, back-illuminated charge-coupled devices for astronomy and astrophysics. The CCDs are fabricated on
high-resistivity substrates and are typically 200–300 μm thick for improved near-infrared response. The primary
research and development areas include methods to reduce read noise, increase quantum efficiency and readout
speed, and the development of fabrication methods for the efficient production of CCDs for large focal planes.
In terms of noise reduction, we will describe technology developments with our industrial partner Teledyne
DALSA Semiconductor to develop a buried-contact technology for reduced floating-diffusion capacitance, as well
as efforts to develop ”skipper” CCDs with sub-electron noise utilizing non-destructive readout amplifiers allowing
for multiple sampling of the charge packets. Improvements in quantum efficiency in the near-infrared utilizing
ultra-high resistivity substrates that allow full depletion of 500 μm and thicker substrates will be described, as
well as studies to improve the blue and UV sensitivity by investigating the limits on the thickness of the back-side
ohmic contact layer used in the LBNL technology. Improvements in readout speed by increasing the number of
readout ports will be described, including work on high frame-rate CCDs for x-ray synchrotrons with as many as
192 amplifiers per CCD. Finally, we will describe improvements in fabrication methods, developed in the course
of producing over 100 science-grade 2k × 4k CCDs for the Dark Energy Survey Camera.
UV Detection I
Far ultraviolet sensitivity of silicon CMOS sensors
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We describe vacuum ultraviolet sensitivity measurements of a new high performance silicon-based CMOS sensor from
Teledyne Imaging Sensors. These sensors do not require the high voltages of MCP detectors, making them a lower mass
and power alternative to the more mature MCP technology. These devices demonstrate up to 40 percent quantum
efficiency at vacuum ultraviolet wavelengths, either meeting or greatly exceeding 10 percent quantum efficiency across
the entire 100-200 nm wavelength region. As with similar visible sensitive devices, backside illumination results in a
higher quantum efficiency than frontside illumination. Measurements of the vacuum ultraviolet sensitivity of the
Teledyne silicon PIN detectors were made by directing a known intensity of ultraviolet light at discrete wavelengths onto
the test detectors and reading out the resulting photocurrent. The sensitivity of the detector at a given wavelength was
then calculated from the intensity and wavelength of the incoming light and the relative photodiode to NIST-traceable
calibration diode active areas. A custom electromechanical interface was developed to make these measurements within
the SwRI Vacuum Radiometric Calibration Chamber. While still in the single pixel stage, full 1K × 1K focal plane
arrays are possible using existing CMOS readout electronics and hold great promise for inclusion in future spaceflight
instrument concepts.
UV photon-counting CCD detectors that enable the next generation of UV spectroscopy missions: AR coatings that can achieve 80-90% QE
Show abstract
We describe recent progress in the development of anti-reflection coatings for use at UV wavelengths on CCDs
and other Si-based detectors. We have previously demonstrated a set of coatings which are able to achieve
greater than 50% QE in 4 bands from 130nm to greater than 300nm. We now present new refinements of these
AR-coatings which will improve performance in a narrower bandpass by 50% over previous work. Successful test
films have been made to optimize transmission at 190nm, reaching 80% potential transmission.
Cryogenic Detectors
Optical lumped element microwave kinetic inductance detectors
Show abstract
Microwave Kinetic Inductance Detectors, or MKIDs, have proven to be a powerful cryogenic detector technology
due to their sensitivity and the ease with which they can be multiplexed into large arrays. An MKID is an energy
sensor based on a photon-variable superconducting inductance in a lithographed microresonator. It is capable
of functioning as both a photon detector across the electromagnetic spectrum and a particle detector. We have
recently demonstrated the world's first photon-counting, energy-resolving, ultraviolet, optical, and near infrared
MKID focal plane array in the ARCONS camera at the Palomar 200" telescope. Optical Lumped Element (OLE)
MKID arrays have significant advantages over semiconductor detectors such as charge coupled devices (CCDs).
They can count individual photons with essentially no false counts and determine the energy (to a few percent)
and arrival time (to ≈1μs) of every photon, with good quantum efficiency. Initial devices were degraded by
substrate events from photons passing through the Titanium Nitride (TiN) material of the resonator and being
absorbed in the substrate. Recent work has eliminated this issue, with a solution found to be increasing the
thickness of the TiN resonator from 20 to 60 nm.
CMOS Sensors
Backside-illuminated, high-QE, 3e- RoN, fast 700fps, 1760x1680 pixels CMOS imager for AO with highly parallel readout
Show abstract
The success of the next generation of instruments for 8 to 40-m class telescopes will depend upon improving the image
quality (correcting the distortion caused by atmospheric turbulence) by exploiting sophisticated Adaptive Optics (AO)
systems. One of the critical components of the AO systems for the E-ELT has been identified as the Laser/Natural Guide
Star (LGS/NGS) WaveFront Sensing (WFS) detector. The combination of large format, 1760x1680 pixels to finely
sample (84x84 sub-apertures) the wavefront and the spot elongation of laser guide stars, fast frame rate of 700 (up to
1000) frames per second, low read noise (< 3e-), and high QE (> 90%) makes the development of such a device
extremely challenging. Design studies by industry concluded that a thinned and backside-illuminated CMOS Imager as
the most promising technology. This paper describes the multi-phased development plan that will ensure devices are
available on-time for E-ELT first-light AO systems; the different CMOS pixel architectures studied; measured results of
technology demonstrators that have validated the CMOS Imager approach; the design explaining the approach of
massive parallelism (70,000 ADCs) needed to achieve low noise at high pixel rates of ~3 Gpixel/s ; the 88 channel
LVDS data interface; the restriction that stitching (required due to the 5x6cm size) posed on the design and the solutions
found to overcome these limitations. Two generations of the CMOS Imager will be built: a pioneering quarter sized
device of 880x840 pixels capable of meeting first light needs of the E-ELT called NGSD (Natural Guide Star Detector);
followed by the full size device, the LGSD (Laser Guide Star Detector). Funding sources: OPTICON FP6 and FP7 from
European Commission and ESO.
High-performance CMOS image sensors at BAE SYSTEMS Imaging Solutions
Show abstract
In this paper, we present an overview of high-performance CMOS image sensor products developed at BAE SYSTEMS
Imaging Solutions designed to satisfy the increasingly challenging technical requirements for image sensors used in
advanced scientific, industrial, and low light imaging applications. We discuss the design and present the test results of a
family of image sensors tailored for high imaging performance and capable of delivering sub-electron readout noise,
high dynamic range, low power, high frame rates, and high sensitivity. We briefly review the performance of the
CIS2051, a 5.5-Mpixel image sensor, which represents our first commercial CMOS image sensor product that
demonstrates the potential of our technology, then we present the performance characteristics of the CIS1021, a full HD
format CMOS image sensor capable of delivering sub-electron read noise performance at 50 fps frame rate at full HD
resolution. We also review the performance of the CIS1042, a 4-Mpixel image sensor which offers better than 70% QE
@ 600nm combined with better than 91dB intra scene dynamic range and about 1 e- read noise at 100 fps frame rate at
full resolution.
CMOS and Hybrid X-Ray Detectors
Recent progress on developments and characterization of hybrid CMOS x-ray detectors
Show abstract
Future space-based X-ray telescope missions are likely to have significantly increased demands on detector read out
rates due to increased collection area, and there will be a desire to minimize radiation damage in the interests of
maintaining spectral resolution. While CCDs have met the requirements of past missions, active pixel sensors are likely
to be a standard choice for some future missions due to their inherent radiation hardness and fast, flexible read-out
architecture. One form of active pixel sensor is the hybrid CMOS sensor. In a joint program of Penn State University
and Teledyne Imaging Sensors, hybrid CMOS sensors have been developed for use as X-ray detectors. Results of this
development effort and tests of fabricated detectors will be presented, along with potential applications for future
missions.
Characterization of an x-ray hybrid CMOS detector with low interpixel capacitive crosstalk
Show abstract
We present the results of x-ray measurements on a hybrid CMOS detector that uses a H2RG ROIC and a unique
bonding structure. The silicon absorber array has a 36μm pixel size, and the readout array has a pitch of 18μm;
but only one readout circuit line is bonded to each 36x36μm absorber pixel. This unique bonding structure gives
the readout an effective pitch of 36μm. We find the increased pitch between readout bonds significantly reduces
the interpixel capacitance of the CMOS detector reported by Bongiorno et al. 20101 and Kenter et al. 2005.2
Development of monolithic CMOS detectors as x-ray imaging spectrometers
Show abstract
We present preliminary results from our ongoing program to develop CMOS detectors as single photon counting,
soft X-ray imaging spectrometers. The Smithsonian Astrophysical Observatory in collaboration with SRI International/
Sarnoff has been developing monolithic CMOS detectors optimized for x-ray astronomy. Our latest
detector consists of an array of 1k × 1k 16 μm pixels manufactured on 15μm epitaxial Si. These detectors are
designed to be packaged and thinned for back illumination. The devices have on-chip CDS and are optimized
to have high (~ 40 frame/sec) read-out rates. Such monolithic CMOS imaging sensors would be ideal candidate
detectors for the focal planes of space-borne soft x-ray astronomy missions. The high through-put, low noise and
excellent low energy response, provide high dynamic range and good time resolution; bright and time varying
x-ray features could be temporally and spectrally resolved without saturation or photon pile-up.
Focal Plane Arrays
A gigapixel commercially manufactured cryogenic camera for the J-PAS 2.5m survey telescope
Show abstract
The J-PAS (Javalambre Physics-of-the-Accelerating-Universe Astrophysical Survey) project will perform a five-year
survey of the northern sky from a new 2.5m telescope in Teruel, Spain. We describe the design concept of a complete
cryogenic camera with a mosaic focal plane and 1.2 gigapixel science array which is to be commercially supplied. The
focal plane is contained within a novel liquid-nitrogen-cooled vacuum cryostat, with proximity drive electronics
designed to achieve a 4 e- readout noise from the 224-channel CCD system.
GPC1 and GPC2: the Pan-STARRS 1.4 gigapixel mosaic focal plane CCD cameras with an on-sky on-CCD tip-tilt image compensation
Show abstract
We will report on the on-sky, on-CCD, tip-tilt image compensation performance of GPC1, the 1.4 gigapixel mosaic focal
plane CCD camera for wide field surveys with a 7 square degree field of view. The camera uses 60 Orthogonal Transfer
Arrays (OTAs) with a novel 4 phase pixel architecture and the STARGRASP controller for closed loop multi-guide star
centroiding and image correction. The Pan-STARRS project is also constructing GPC2, the second 1.4 gigapixel camera
using 64 OTAs. GPC2 will include design enhancements over GPC1 including a new generation of OTAs, titanium
mosaic focal plane with adjustable three point kinematic mounts, cyro flex wiring and the recent software distributed
over 32 controllers. We will discuss the design, cost, schedule, tools developed, shortcomings and future plans for the
two largest digital cameras in the world.
Development of the LSST raft tower modules
Show abstract
The science focal plane of the Large Synoptic Survey Telescope is made up of 21 modules designated "raft towers".
Each raft tower module (RTM) is an autonomous, fully-testable and serviceable 144 Mpixel imager consisting of nine
highly-segmented CCDs with complete readout electronics chain. To minimize noise and obscuration the RTM is
housed in a compact enclosure fully contained within the camera cryostat. The RTM is required to meet strict
performance goals for image plane flatness, readout speed, noise, and power dissipation. Key components include the
4K × 4K fully-depleted CCDs with 16 outputs each, ceramic CCD support structure, and ASIC electronics for video
processing and clock/bias generation. In addition to CCD signal handling, the RTM electronics also includes monitoring
for temperature, voltage, and current, makeup heater control, ASIC configuration and readback, powerdown modes, and
specialized diagnostic outputs. Digitized data are transmitted out of the camera cryostat over a single 3Gb/s serial link.
4Kx4K format 10-micron pixel pitch H4RG-10 hybrid CMOS silicon visible focal plane array for space astronomy
Show abstract
Teledyne’s silicon hybrid CMOS focal plane array technology has matured into a viable, high performance and high-
TRL alternative to scientific CCD sensors for space-based applications in the UV-visible-NIR wavelengths. This paper
presents the latest results from Teledyne’s low noise silicon hybrid CMOS visible focal place array produced in 4K×4K format with 10 μm pixel pitch. The H4RG-10 readout circuit retains all of the CMOS functionality (windowing, guide
mode, reference pixels) and heritage of its highly successful predecessor (H2RG) developed for JWST, with additional
features for improved performance. Combined with a silicon PIN detector layer, this technology is termed HyViSI™
(Hybrid Visible Silicon Imager). H4RG-10 HyViSI™ arrays achieve high pixel interconnectivity (<99.99%), low
readout noise (<10 e- rms single CDS), low dark current (<0.5 e-/pixel/s at 193K), high quantum efficiency (<90%
broadband), and large dynamic range (<13 bits). Pixel crosstalk and interpixel capacitance (IPC) have been predicted
using detailed models of the hybrid structure and these predictions have been confirmed by measurements with Fe-55 Xray
events and the single pixel reset technique. For a 100-micron thick detector, IPC of less than 3% and total pixel
crosstalk of less than 7% have been achieved for the HyViSI™ H4RG-10. The H4RG-10 array is mounted on a
lightweight silicon carbide (SiC) package and has been qualified to Technology Readiness Level 6 (TRL-6). As part of
space qualification, the HyViSI™ H4RG-10 array passed radiation testing for low earth orbit (LEO) environment.
X-Ray Detectors I
New simulation and measurement results on gateable DEPFET devices
Show abstract
To improve the signal to noise level, devices for optical and x-ray astronomy use techniques to suppress background
events. Well known examples are e.g. shutters or frame-store Charge Coupled Devices (CCDs). Based
on the DEpleted P-channel Field Effect Transistor (DEPFET) principle a so-called Gatebale DEPFET detector
can be built. Those devices combine the DEPFET principle with a fast built-in electronic shutter usable for
optical and x-ray applications. The DEPFET itself is the basic cell of an active pixel sensor build on a fully
depleted bulk. It combines internal amplification, readout on demand, analog storage of the signal charge and a
low readout noise with full sensitivity over the whole bulk thickness. A Gatebale DEPFET has all these benefits
and obviates the need for an external shutter.
Two concepts of Gatebale DEPFET layouts providing a built-in shutter will be introduced. Furthermore proof
of principle measurements for both concepts are presented. Using recently produced prototypes a shielding of
the collection anode up to 1 • 10−4 was achieved. Predicted by simulations, an optimized geometry should result
in values of 1 • 10−5 and better. With the switching electronic currently in use a timing evaluation of the shutter
opening and closing resulted in rise and fall times of 100ns.
Design and performance of the eROSITA focal plane instrumentation
Show abstract
We developed and tested X-ray PNCCD focal plane detectors for the eROSITA (extended ROentgen Survey with an
Imaging Telescope Array) space telescope. General scientific goal of the eROSITA project is the exploration of the X-ray
universe in the energy band from about 0.2 keV up to 10 keV with excellent energy, time, and spatial resolution in
combination with large effective telescope areas. The observational program divides into an all-sky survey and pointed
observations. The mission duration is scheduled for 7.5 years. The German instrument will be launched in near future to
the Lagrange point L2 on the Russian satellite SRG. The detection of single X-ray photons with precise information
about their energy, angle of incidence and time is accomplished for eROSITA by an array of seven identical and
independent PNCCD cameras. Each camera is assigned to a dedicated mirror system of Wolter-I type. The key
component of the camera is a 5 cm • 3 cm large, back-illuminated, 450 μm thick and fully depleted frame store PNCCD
chip. This chip is a further development of the sensor type that is in operation as focal plane detector on the XMMNewton
satellite since launch in 1999 to date. Development and production of the CCDs for the eROSITA project were
performed by the MPI Halbleiterlabor, as already in the past for the XMM-Newton project. According to the status of
the project, a complete design of the seven flight cameras including the camera electronics and the filter wheel has been
developed. Various functional and performance tests have been accomplished for a detailed characterization of the
eROSITA camera system. We focus here especially on the focal plane detector design and the performance of the
detectors, which are essential for the success of the X-ray astronomy space project.
Integration and calibration of DEPFET macropixel detectors for MIXS
Petra Majewski,
Florian Aschauer,
Alexander Bähr,
et al.
Show abstract
The Mercury Imaging X-ray Spectrometer (MIXS) is an instrument on board of the 5th ESA cornerstone mission
BepiColombo. This Spectrometer comprises two instruments for imaging x-ray spectroscopy of the Mercury
surface. The detector plane arrays (DPA) for the energy and spatial resolved detection of x-rays are based on
DEPFET (Depleted P-channel FET) macropixel detectors with 64×64 pixel each and 300×300 μm2 pixel
size. The MIXS target energy band is from 0.5 to 7 keV with an energy resolution better than 200 eV at 1 keV
at mission end. This allows to access the Fe-L line at about 0.7 keV, which was not accessible to previous
instruments, and to separate the x-ray lines of the elements of interest.
Before a detector chip is integrated into a detector module, it is electrically pre-characterized in order to select
only the best chips for the complex and time-consuming integration. The high degree of complexity of the
integration process comes from the need to thermally decouple the detector chip from its readout and steering
ASICs by a sophisticated mechanical structure, due to the limited amount of cooling power available for the
instrument. After the spectroscopic characterization of the detector modules, the flight and flight spare detectors
were calibrated at the PTB (Physikalisch-Technische Bundesanstalt) beamlines at the BESSY-II synchrotron.
We report on the pre-characterization, integration, qualification and calibration of MIXS flight and flight spare
detectors, which is now successfully completed.
Performance of new generation swept charge devices for lunar x-ray spectroscopy on Chandrayaan-2
Show abstract
The Chandrayaan-2 Large Area Soft X-ray spectrometer (CLASS) is due to be launched by the Indian Space Research
Organisation (ISRO) in 2014. It will map the elemental composition of the lunar surface, building on the Chandrayaan-1
X-ray spectrometer (C1XS) heritage. CLASS will use an array of e2v technologies CCD236 swept charge devices (SCD)
providing an active detector area of approximately 64 cm2, almost three times the active area of C1XS which used the
first generation of SCD, the CCD54. The CCD236 is designed as a soft X-ray detector, 0.8 keV to 10 keV, and benefits
from improvements in design to allow for increased detector area, a reduction in split X-ray events and improvements to
radiation hardness. This paper describes the investigation into the performance requirements of the CCD236, focussing
on an optimisation of the energy resolution of a device irradiated to the estimated worse case end of life proton fluence.
Development status of a CZT spectrometer prototype with 3D spatial resolution for hard x-ray astronomy
Show abstract
The development of new focusing optics based on wide band Laue lenses operating from ~60 keV up to several hundred
keV is particularly challenging. This type of hard X-ray or gamma ray optics requires a high performance focal plane
detector in order to exploit to the best their intrinsic capabilities. We describe a three dimensional (3D) position sensitive
detector prototype suitable as the basic module for a high efficiency Laue lens focal plane detector. This detector
configuration is currently under study for use in a balloon payload dedicated to performing a high significance
measurement of the polarization status of the Crab between 100 and 500 keV. The prototype is made by packing 8 linear
modules, each composed of one basic sensitive unit bonded onto a thin supporting ceramic layer. Each unit is a drift strip
detector based on a CZT crystal, irradiated transversally to the electric field direction. The anode is segmented into 8
detection cells, each comprising one collecting strip and 8 surrounding drift strips. The drift strips are biased by a voltage
divider. The cathode is divided into 4 horizontal strips for the reconstruction of the Z interaction position. The detector
readout electronics is based on RENA-3 ASIC and the data handling system uses a custom electronics based on FPGA to
provide the ASIC setting, the event handling logic, and the data acquisition. This paper mainly describes the components
and the status of the undergoing activities for the construction of the proposed 3D CZT prototype and shows the results
of the electronics tests.
IR Detectors I
Evaluation and optimization of NIR HgCdTe avalanche photodiode arrays for adaptive optics and interferometry
Show abstract
The performance of the current high speed near infrared HgCdTe sensors operating in fringe trackers, wavefront sensors
and tip-tilt sensors is severely limited by the noise of the silicon readout interface circuit (ROIC), even if state-of-the- art
CMOS designs are used. A major improvement can only be achieved by the amplification of the photoelectron signal
directly at the point of absorption by means of avalanche gain inside the infrared pixel. Unlike silicon, HgCdTe offers
noiseless avalanche gain. This has been verified with the LPE grown 320x256 pixel λc=2.5 μm HgCdTe eAPD arrays
from SELEX both on a prototype ROIC called SWALLOW and on a newly developed ROIC, specifically designed for
AO applications, called SAPHIRA. The novel features of the new SAPHIRA ROIC, which has 32 parallel video channels
operating at 5 MHz, will be described, together with the new high speed NGC data acquisition system. Performance
results will be discussed for both ROICs. The LPE material on the SWALLOW prototype was excellent and allowed
operation at an APD gain as high as 33. Unfortunately, the LPE material of the first devices on the SAPHIRA ROIC suffers
from problems which are now understood. However, due to the excellent performance of the SAPHIRA ROIC even
with the limitations of present HgCdTe material, it is possible with simple double correlated sampling to detect test patterns
with signal levels of 1 electron. An outlook will be given on further developments of heterojunctions grown by
MOVPE, which eventually may replace eAPD arrays grown by LPE.
Operation and performance of new NIR detectors from SELEX
Show abstract
The European Space Agency (ESA) has funded SELEX Galileo, Southampton, UK to develop large format near infrared
(NIR) detectors for its future space and ground based programmes. The UKATC has worked in collaboration with
SELEX Galileo to test and characterise the new detectors produced during phase-1 of the development. In order to
demonstrate the detector material performance, the HgCdTe (MCT) detector diodes (grown on GaAs substrate through
MOVPE process in small 320×256, 24μm pixel format) are hybridised to the existing SELEX Galileo SWALLOW
CMOS readout chip. The substrate removed and MCT thinned detector arrays were then tested and evaluated at the
UKATC following screening tests at SELEX. This paper briefly describes the test setup, the operational aspects of the
readout multiplexer and presents the performance parameters of the detector arrays including: conversion gain, detector
dark current, read noise, linearity, quantum efficiency and persistence for various detector temperatures between 80K
and 140K.
Development and production of the H4RG-15 focal plane array
Show abstract
In preparation for the large number of infrared pixels required in the era of Extremely Large Telescopes, Teledyne, in
partnership with the University of Hawaii and GL Scientific, has been funded to develop the next generation of largeformat infrared focal plane array for ground-based astronomy; the 4096 × 4096 pixel (15 micron pitch) H4RG-15. Teledyne has successfully designed, produced, and tested the first generation H4RG-15 prototype arrays. This paper reports on the functionality and performance test results of the H4RG-15 prototypes and provides status of the 2012 pilot production effort.
Performance of the first HAWAII 4RG-15 arrays in the laboratory and at the telescope
Show abstract
The primary goal of the HAWAII 4RG-15 (H4RG-15) development is to provide a 16 megapixel 4096x4096 format at
significantly reduced price per pixel while maintaining the superb low background performance of the HAWAII 2RG
(H2RG). The H4RG-15 design incorporates several new features, notably clocked reference output and interleaved
reference pixel readout, that promise to significantly improve noise performance while the reduction in pixel pitch from
18 to 15 microns should improve transimpedance gain although at the expense of some degradation in full well and
crosstalk. During the Phase-1 development, Teledyne has produced and screen tested six hybrid arrays. In preparation for
Phase-2, the most promising of these are being extensively characterized in the University of Hawaii’s (UH) ULBCam
test facility originally developed for the JWST H2RG program. The end-to-end performance of the most promising array
has been directly established through astronomical imaging observations at the UH 88-inch telescope on Mauna Kea. We
report the performance of these Phase-1 H4RG-15s within the context of established H2RG performance for key
parameters (primarily CDS read noise), also highlighting the improvements from the new readout modes.
IR Detectors II
Read noise for a 2.5µm cutoff Teledyne H2RG at 1-1000Hz frame rates
Show abstract
A camera operating a Teledyne H2RG in H and Ks bands is under construction at Caltech to serve as a near-infrared tip-tilt sensor for the Keck-1 Laser Guide Star Adaptive Optics system. After imaging the full field for acquisition, small readout windows are placed around one or more natural guide stars anywhere in the AO corrected field of view. Windowed data may be streamed to RAM in the host for a limited time then written to disk as a single file, analogous to a “film strip”, or be transmitted indefinitely via a second fiber optic output to a dedicated computer providing real time control of the AO system. The various windows can be visited at differing cadences, depending on signal levels. We describe a readout algorithm that maximizes exposure duty cycle, minimizes latency, and achieves very low noise by resetting infrequently then synthesizing exposures from Sample Up The Ramp data. To illustrate which noise sources dominate under various conditions, noise measurements are presented as a function of synthesized frame rate and window sizes for a range of detector temperatures. The consequences of spatial variation in noise properties, and dependence on frame rate and temperature are discussed, together with probable causes of statistical outliers.
H2RG focal plane array and camera performance update
Show abstract
Teledyne’s H2RG focal plane arrays have been widely used in scientific infrared and visible instruments for ground-based and space-based telescopes. The majority of applications use the H2RG with 2.5 micron cutoff HgCdTe detector pixel at an operating temperature of ~77 K (LN2). The exceptionally low dark current of the 2.5 micron H2RG allows for operation at higher temperatures which facilitates simplified instrument designs and therefore lower instrument cost. Performance data of 2.5 micron H2RG arrays at 77K, 100 K, and 120 K are presented and are discussed as a function of detector bias and pixel readout rate. This paper also presents performance data of 1.75 micron and 5.3 micron H2RG focal plane arrays and discusses some of the inherent performance differences compared to 2.5 micron cutoff arrays. A complete infrared camera system that uses the H2RG focal plane array and SIDECAR ASIC focal plane electronics is introduced.
AQUARIUS: the next generation mid-IR detector for ground-based astronomy
Show abstract
ESO has recently funded the development of the AQUARIUS detector at Raytheon Vision Systems, a new mega-pixel
Si:As Impurity Band Conduction array for use in ground based astronomical applications at wavelengths between 3 – 28
μm. The array has been designed to have low noise, low dark current, switchable gain and be read out at very high frame
rates. It has 64 individual outputs capable of pixel read rates of 3MHz, implying continuous data-rates in excess of 300
Mbytes/second. It is scheduled for deployment into the VISIR instrument at the VLT in 2012, for next generation VLTI
instruments and base-lined for METIS, the mid-IR candidate instrument for the E-ELT. A new mid-IR test facility has
been developed for AQUARIUS detector development which includes a low thermal background cryostat, high speed
cryogenic pre-amplification and high speed data acquisition and detector operation at 5K. We report on all the major
performance aspects of this new detector including conversion gain, read noise, dark generation rate, linearity, well
capacity, pixel operability, low frequency noise, persistence and electrical cross-talk. We describe the many possible
readout modes of this detector and their application. We also report on external issues with the operation of these
detectors at such low temperatures. Finally we report on the electronic developments required to operate such a detector
at the required high data rates and in a typical mid-IR instrument.
IR Detectors III
Pixel classification for the JWST fine guidance sensor
Show abstract
The James Webb Space Telescope Fine Guidance Sensor makes use of three 2048x2048 five micron cutoff HAWAII-2RG HgCdTe detectors from Teledyne Imaging Systems. The FGS consists of two Guider channels and a Near-InfraRed Imager and Slitless Spectrograph (NIRISS) channel. We report here on the characterization of the flight
detectors at the sub-system level and after integration to the flight instrument. The FGS-Guider has a number of unique
readout modes which are required to support observatory operations. Of critical importance is the identification and
classification of pixels which, if left unmasked or unprocessed, would compromise the guider performance. We report
on these classification methods and on the detailed behaviour of key bad pixel types which can impact guider
performance.
Space Radiation Damage
CMOS sensor and camera for the PHI instrument on board Solar Orbiter: evaluation of the radiation tolerance
J. Piqueras,
K. Heerlein,
S. Werner,
et al.
Show abstract
The ESA/NASA Solar Orbiter mission, to be launched in 2017, will explore the Sun at a much closer distance
than any previous solar observatory. On board the spacecraft, a high-resolution magnetograph (PHI) will provide
two-dimensional measurements of the photospheric vector magnetic field and line-of-sight velocity. The
environmental conditions encountered during the mission, together with the stringent performance requirements
of the instrument, define the set of specifications for the camera system. A custom designed CMOS sensor (with
2048×2050 pixels) has been developed to fulfill the aimed radiation hardness and performance. This sensor must
demonstrate a cadence above 10 fps with a full-well capacity higher than 105 electrons in a 10-μm pixel pitch.
We report the characterization and qualification tests. The radiation test campaign has been completed up to
a TID of 150 krad(Si), proton fluence up to 4 × 1011 at 10 MeV and 2 × 1011 at 20 MeV, and with heavy ions
to check for latch-up and SEFI failures. In parallel, a radiation tolerant camera electronic readout system has
been built to control the sensor and readout images, digitize the data, and communicate with the data handling
system of the PHI instrument. In addition, we present the main issues related to the camera design and future
perspectives.
Modelling charge transfer in a radiation damaged charge coupled device for Euclid
Show abstract
As electrons are transferred through a radiation damaged Charge Coupled Device (CCD), they may encounter traps in
the silicon in which they will be captured and subsequently released. This capture and release of electrons can lead to a
'smearing' of the image. The dynamics of the trapping process can be described through the use of Shockley-Read-Hall
theory, in which exponential time constants are used to determine the probability of capture and release. If subjected to a
hostile radiation environment, such as in space where the dominant charged particle is the proton, these incident protons
can cause displacement damage within the CCD and lead to the formation of stable trap sites. As the trap density
increases, the trapping and release of signal electrons can have a major impact on the Charge Transfer Efficiency (CTE)
to the detriment of device performance. As the science goals for missions become ever more demanding, such as those
for the ESA Euclid and Gaia missions, the problem of radiation damage must be overcome. In order to gain a deeper
understanding of the trapping process and the impact on device performance, a Monte Carlo simulation has been
developed to model the transfer of charge in a radiation damaged CCD. This study investigates the various difficulties
encountered when developing such a model: the incorporation of appropriate clocking mechanisms, the use of suitable
trap parameters and their degeneracy, and the development of methods to model the charge storage geometry within a
pixel through the use of three-dimensional Silvaco simulations.
Assessment of proton radiation-induced charge transfer inefficiency in the CCD273 detector for the Euclid Dark Energy Mission
Show abstract
Euclid is a medium class mission selected for launch in 2019, with a primary goal to study the dark universe using the
weak lensing and baryonic acoustic oscillations techniques. Weak lensing depends on accurate shape measurements,
therefore it is beneficial that the effects of radiation-induced charge transfer inefficiency (CTI) in the Euclid CCD over
the six year mission are understood and minimised. This paper describes the initial evaluation of the tolerance to
radiation induced charge transfer inefficiency (CTI) of the CCD273 produced by e2v technologies plc, making
comparisons with the previous CCD selected for Euclid the CCD203. The CCD273 benefits from the inclusion of a
charge injection structure for trap suppression and a reduction in the register channel width. The improvement in
tolerance to radiation induced serial CTI achieved by reducing the channel width from 50 μm to 20 μm was measured
experimentally to be a factor of 1.7, which compares well to a factor of 1.9 found using a charge volume model
Mitigating radiation-induced charge transfer inefficiency in full-frame CCD applications by 'pumping' traps
Show abstract
The charge transfer efficiency of a CCD is based on the average level of signal lost per pixel over a number of transfers. This value can be used to directly compare the relative performances of different structures, increases in radiation damage or to quantify improvements in operating parameters. This number does not however give sufficient detail to mitigate for the actual signal loss/deference in either of the transfer directions that may be critical to measuring shapes to high accuracy, such as those required in astronomy applications (e.g. for Gaia’s astrometry or the galaxy distortion measurements for Euclid) based in the radiation environment of space. Pocket-pumping is an established technique for finding the location and activation levels of traps; however, a number of parameters in the process can also be explored to identify the trap species and location to sub-pixel accuracy. This information can be used in two ways to increase the sensitivity of a camera. Firstly, the clocking process can be optimised for the time constant of the majority of traps in each of the transfer directions, reducing deferred charge during read out. Secondly, a correction algorithm can be developed and employed during the post-processing of individual frames to move most of any deferred signal back into the charge packet it originated from. Here we present the trap-pumping techniques used to optimise the charge transfer efficiency of p- and n-channel e2v CCD204s and describe the use of trap-pumped images for on-orbit calibration and ground based image correction algorithms.
X-Ray Detectors II
Characterization of the silicon drift detector for NICER instrument
Show abstract
We have studied timing properties of the Amptek Silcon Drift Detectors (SDD) using pulsed X-ray source
designed at NASA Goddard Space Flight Center. The proposed Neutron Star Interior Composition Explorer
(NICER) mission will use 56 of these detectors as X-ray sensors in an attached payload to the International
Space Station to study time variability of millisecond X-ray pulsars. Using a rastered pinhole we have measured
the delay times for single X-ray photons as a function of the impact position on the detector, as well as signal
rise time as a function of impact position. We find that the interdependence of these parameters allows us to
determine photon position on the detector by measuring the signal rise time, and, improve the accuracy of the
photon arrival time measurement.
Development of a laboratory based XRF facility for measuring elemental abundance ratios in planetary analogue powder samples
Show abstract
This paper describes the use of a swept-charge device (SCD) silicon X-ray detector in a laboratory based X-ray
fluorescence (XRF) facility for calculating elemental abundance ratios from planetary analogue powder samples. The
facility was developed to support the Chandrayaan-1 X-ray Spectrometer (C1XS) detector development and calibration
activities prior to the flight of the instrument onboard the Indian Space Research Organisation (ISRO) Chandrayaan-1
mission to the Moon in 2008. The test facility has subsequently been used to carry out XRF analysis of homogenous
samples made from mixtures of MgO, Al2O3 and SiO2 powders, all of grain size <44 μm, across a range of mixture ratios
and at a high level of X-ray flux data in order to develop an algorithm which will allow the calculation of elemental
abundance ratios. This paper also presents an analysis of XRF data collected from lunar regolith simulant JSC-1A and an
Etna Basalt powder sample to enable calibration of various model parameters. The operation of the SCD, the XRF test
facility, the sample preparation methodology and the process of obtaining elemental abundance ratios from planetary
analogue samples using the test facility are discussed in this paper.
A compact high-speed pnCCD camera for optical and x-ray applications
Show abstract
We developed a camera with a 264 × 264 pixel pnCCD of 48 μm size (thickness 450 μm) for X-ray and optical
applications. It has a high quantum efficiency and can be operated up to 400 / 1000 Hz (noise≈ 2:5 ē ENC
/ ≈4:0 ē ENC). High-speed astronomical observations can be performed with low light levels. Results of test
measurements will be presented. The camera is well suitable for ground based preparation measurements for
future X-ray missions. For X-ray single photons, the spatial position can be determined with significant sub-pixel
resolution.
Testing
Charge diffusion measurement in fully depleted CCD using 55Fe X-rays
Show abstract
Tight requirements on the Large Synoptic Survey Telescope point spread function (PSF) demand sensor contribution
to PSF be both small and well characterized. The sensor PSF is determined by the lateral charge
diffusion on the drift path from the photon conversion point to the gates. The maximum drift path occurs
for photons converted at the window, for blue optical photons in particular. Charges generated at the window
surface undergo "worst case" charge spreading and the blue optical PSF is used to characterize the sensor's PSF.
Different techniques for charge diffusion characterization have been developed, each with its own systematics
and measurement difficulties. A new way to measure charge diffusion using an X-ray source is presented. We
demonstrate the effectiveness and limitations of our technique and discuss relation of charge diffusion value
obtained with X-ray measurements to sensor PSF.
A test-based comparison between technologies implemented in commercial cameras for high contrast imaging applications
Show abstract
LAM is developing a high-contrast imaging testbeds for in-lab demonstration of new instrumental concepts requiring
high contrast imaging: in particular, for solar and stellar coronagraphy applications. In such applications, a faint target
has to be detected close to a very bright source. For these test-benches, a high-dynamic range detector is required to
characterize and/or to determine the performance of a new concept. Beyond the capability to detect the target, an
imaging detector has to be accurate, reliable and provide reproducible performances.
In order to identify a commercial camera for the development of laboratory demonstrators working with high contrast
scenes, we carried out a test campaign at the Laboratoire d’Astrophysique de Marseille (LAM) evaluating several
cameras implementing different detector technologies. This paper presents the results of the test campaign, carried out at
LAM, providing a quantitative comparison between the investigated technologies
Electronics/Readout
Development of a test system for the characterisation of DCDS CCD readout techniques
Show abstract
A system has been designed and built for developing the technique of Digital Correlated Double Sampling (DCDS) to
eliminate reset noise in CCD camera systems. It allows a wide range of DCDS methods and algorithms to be tested and
is based on the CCD203 from e2v technologies. The test system is described and sub-system noise characterisation test
results are presented and compared with the theoretically expected performance. Furthermore, tests based on the
weighted averaging of samples are described and results presented.
Beating the 1/f noise limit on charge coupled devices
Show abstract
Scientific CCD detectors are typically readout using the Correlated Double Sampling (CDS) technique. At low
pixel rates, noise of ~2e- RMS is typically achieved. The limitation for reaching lower noise comes from the 1/f
component on the output of the CCD, and this noise cannot be eliminated using CDS. A new readout technique
based on a digital filter is presented here for suppressing the 1/f. Using this new technique a noise of 0.4e- is
achieved.
Reducing the read noise of HAWAII-2RG detector systems with improved reference sampling and subtraction (IRS2)
Show abstract
IRS2 is a Wiener-optimal approach to using all of the reference information that Teledyne’s HAWAII-2RG
(H2RG) detector array provides. Using a new readout pattern, IRS2 regularly interleaves reference pixels with
the normal pixels during readout. This differs from conventional clocking, in which the reference pixels are read
out infrequently, and only in a few rows and columns around the outside edges of the detector array. During
calibration, the data are processed in Fourier space, which is close to the noise’s eigenspace. Using IRS2, we have
reduced the read noise of the James Webb Space Telescope (JWST) Near Infrared Spectrograph’s (NIRSpec)
H2RGs by 15% compared to conventional readout. We are attempting to achieve further gains by calibrating out
a recently recognized non-stationary noise component that appears at the frame rate. Teledyne’s new HAWAII-
4RGs (H4RG) build in a flexible capability to interleave reference pixels. We eagerly look forward to applying
IRS2 techniques to H4RGs when the opportunity arises.
Temperature dependence of the dark current and activation energy at avalanche onset of GaN avalanche photodiodes
Show abstract
We report a study of the performance of an avalanche photodiode (APD) as a function of temperature from
564 K to 74 K. The dark current at avalanche onset decreases from 564 K to 74 K by approximately a factor of
125 and from 300 K to 74K the dark current at avalanche offset is reduced by a factor of about 10. The drop
would have been considerably larger if the activation energy at avalanche onset (Ea) did not also decrease with
decreasing temperature. These data give us insights into how to improve the single-photon counting performance
of a GaN based ADP.
CCDs II
Device modelling and model verification for the Euclid CCD273 detector
Show abstract
Euclid is one of the M-class missions selected for the next phase of ESA’s long-term Cosmic Vision programme. The
primary goal of this mission is to observe the distribution and shapes of distant galaxies, with the aim of mapping and
characterising the dark energy which makes up about 70% of the universe. This will be achieved by measuring the
effects of weak lensing on the captured images, in terms of the distortion caused to the elipticity of galaxy shapes [1].
The e2v CCD273 was designed for the Euclid mission and is adapted from an older design (the CCD203) with changes
made to improve CTE under irradiation by solar protons. Reducing the effects of radiation damage in the image sensor
will result in images which have minimal distortion.
This paper is focused on the on-going development and verification of 3D device models and their integration with
Monte Carlo radiation damage models. Parameters such as charge interaction volume versus signal size, pixel full well
capacity, and charge transfer behaviour for both the parallel and serial registers will be discussed.
The main mission goals are aimed at measuring distortion due to weak lensing, so it is important to differentiate this
from distortion due to radiation damage. This work will eventually lead to a method of post processing images to remove
the effects of radiation damage.
CCDs III
Charge-coupled devices for the ESA PLATO M-class Mission
Show abstract
PLATO is a candidate mission for an European Space Agency M-class launch opportunity. The project aims to detect
exo-planets from their transits across host stars and to characterise those stars by studying their oscillations, hence the
name PLATO for, PLAnetary Transits and Oscillations of stars. In order to achieve this aim the mission proposes to fly a
satellite with a focal plane of up to 34 mini-telescopes, each containing 4 large area back illuminated Charge-Coupled
Devices (CCDs) to provide ultra high precision photometry. If successful, the satellite will have nearly 0.9 m2 of image
sensors and will be by far the largest composite detector focal plane ever flown. To meet the mission requirements e2v
have developed the CCD270 which has 4510 by 4510 pixels, each pixel is 18 μm by 18 μm, in a development funded by
the European Space Agency. This large area (81 mm x 81 mm) full frame image sensor is intended for precision
photometry with a dynamic range in excess of 30,000. The CCD270 has been manufactured with a thinner gate dielectric
and a higher buried channel dose than standard devices to increase the full well capacity in the image area. The
additional advantages of the thinner gate are lower power dissipation, smaller clock voltage swing for standard channel
doses and higher tolerance to ionising radiation. This paper describes the imager sensor in detail and focuses on the novel
aspects of the device, package and interface.
Persistence and charge diffusion in an E2V CCD42-90 deep-depletion CCD
Show abstract
The ESPaDOnS spectrograph at the Canada-France-Hawaii Telescope was recently upgraded to use an E2V CCD42-90
deep-depletion CCD. While changing to this device from a standard silicon CCD42-90 had many benefits such as much
higher red QE and much lower fringing, it was also found that the new device exhibited persistence. After talking with
E2V, a solution to the persistence was found, but this resulted in reduced resolution on the spectrograph from charge
diffusion. This paper will describe the solution found to allow the detector to run with no persistence and with limited
charge diffusion.
Recent astronomical detector development at the University of Arizona
Show abstract
The University of Arizona Imaging Technology Laboratory (ITL) has been developing back illuminated detectors and
detector technologies for several astronomical projects in recent years. These projects include the WIYN telescope One
Degree Imager (ODI) mosaic of Orthogonal Transfer Array CCDs, the VIRUS detectors for the University of Texas'
Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), detector and packaging development for the Large
Synoptic Survey Telescope (LSST), and 10kx10k and 4kx4k CCDs for several instruments. In this paper we discuss
these projects with an emphasis on backside processing issues and detector characterization results which may be
relevant to other groups. We will also focus packaging techniques and metrology for achieving very flat and stable focal
planes. Results will include device flatness at cryogenic temperatures, process yield, photo-response non-uniformity and
cosmetics, quantum efficiency, read noise, linearity, charge transfer efficiency, and photon transfer data.
STA1600LN: low-noise 10560 x 10560 pixel high-resolution CCD for astronomy
Show abstract
The demand from the astronomical community for high resolution low noise CCDs has led to the development of the
STA1600LN, a 10560 × 10560 pixel, 95mm × 95mm, full-frame CCD imager with 9×9 μ2 pixels. The device
improvements include noise reduction to below 3ē at 100kHz, improved quantum efficiency, as well as packaging
developments for improved fill factor in mosaic systems. We provide test results from production devices, along with
updates on scientific systems utilizing the STA1600 for astronomy.
A novel CCD for application in high-frame rate geostationary space-based imaging
Show abstract
The Geostationary Lightning Mapper (GLM) instrument selected to fly on the National Oceanic and Atmospheric
Administration (NOAA) GOES-R Series environmental satellites has very unique requirements as compared to an
imaging array. GLM's requirements to monitor lightning on a continental scale will provide new insight into the
formation, distribution, morphology and evolution of storms.
A 500 frame per second backside illuminated frame transfer CCD imager (STA3900A) with variable pixel size has
been developed to meet these requirements. A variable pixel architecture provides a near uniform mapping of the curved
surface of the earth, while 56 outputs running at 20 MHz yield greater than a 1.1 Gigapixel per second data rate with low
RMS noise and high MTF. This paper will provide detailed information on design trades required. We will report CCD
read noise, dark current, full well capacity, and quantum efficiency (QE).
IR Detectors IV
Performance and calibration of H2RG detectors and SIDECAR ASICs for the RATIR Camera
Show abstract
The Reionization And Transients Infra-Red camera has been built for rapid Gamma-Ray Burst followup and
will provide simultaneous optical and infrared photometric capabilities. The infrared portion of this camera
incorporates two Teledyne HgCdTe HAWAII-2RG detectors, controlled by Teledyne’s SIDECAR ASICs. While
other ground-based systems have used the SIDECAR before, this system also utilizes Teledyne’s JADE2 interface
card and IDE development environment. Together, this setup comprises Teledyne’s Development Kit, which is
a bundled solution that can be efficiently integrated into future ground-based systems. In this presentation, we
characterize the system’s read noise, dark current, and conversion gain.
Hemispherical infrared focal plane arrays: a new design parameter for the instruments
Show abstract
In ground based astronomy, mainly all designs of sky survey telescopes are limited by the requirement
that the detecting surface is flat whereas the focal surface is curved. Two kinds of solution have been
investigated up to now. The first one consists in adding optical systems to flatten the image surface; however this
solution complicates the design and increases the system size. Somehow, this solution increases, in the same
time, the weight and price of the instrument. The second solution consists in curving artificially the focal surface
by using a mosaic of several detectors, which are positioned in a spherical shape. However, this attempt is
dedicated to low curvature and is limited by the technical difficulty to control the detectors alignment and tilt
between each others.
Today we would like to propose an ideal solution which is to curve the focal plane array in a spherical shape,
thanks to our monolithic process developed at CEA-LETI based on thinned silicon substrates which allows a
100% optical fill factor. Two infrared uncooled cameras have been performed, using 320 x 256 pixels and 25 μm
pitch micro-bolometer arrays curved at a bending radius of 80 mm. These two micro-cameras illustrate the
optical system simplification and miniaturization involved by curved focal plane arrays.
Moreover, the advantages of curved detectors on the optical performances (Point Spreading Function), as well as
on volume and cost savings have been highlighted by the simulation of the opto-mechanical architecture of the
spectrometer OptiMOS-EVE for the European Extremely Large Telescope (E-ELT).
Control electronics for large mosaics of SIDECAR ASIC driven detectors
Show abstract
Several of the next generation instruments require high-resolution visible or infrared focal plane arrays that can only be
achieved by building large mosaics of individual detector arrays. A significant step towards enabling these mosaics has
been the introduction of the SIDECAR ASIC by Teledyne Imaging Sensors, a single chip for generating biases and
clocks to the image sensor, and for digitizing up to 36 sensor outputs. To support large detector mosaics, we have
developed a new control electronics approach that operates up to 32 SIDECAR ASIC / HxRG detectors in parallel.
Important properties of the electronics include separately programmable voltage supplies for each ASIC with
programmable over-current and over-voltage protection, synchronized operation of all ASICs, and support for post-processing
of science data like co-adding of frames, sample-up-the-ramp processing, or centroiding. All ASIC and
detector modes are supported, including window/guide mode operation. The electronics uses a full mode CameraLink
interface to provide 680 MBytes/s of sustained bandwidth.
In this paper, we present an overview of the electronics architecture, including the general computer infrastructure for
data acquisition, storage and sharing. We will discuss benefits and features of the chosen approach, and present data
captured using a SIDECAR ASIC and H2RG detector. The effort was funded by NASA's WFIRST project as part of an
initial technology demonstration for large space-based detector mosaics.
Characterization of HAWAII-2RG detector and SIDECAR ASIC for the Euclid mission at ESA
Show abstract
In the frame work of the European Space Agency's Cosmic Vision program, the Euclid mission has the objective to map
the geometry of the Dark Universe. Galaxies and clusters of galaxies will be observed in the visible and near-infrared
wavelengths by an imaging and spectroscopic channel.
For the Near Infrared Spectrometer instrument (NISP), the state-of-the-art HAWAII-2RG detectors will be used,
associated with the SIDECAR ASIC readout electronic which will perform the image frame acquisitions.
To characterize and validate the performance of these detectors, a test bench has been designed, tested and validated.
This publication will present preliminary measurements on dark current, read noise, conversion gain and power
consumption, In summary, the following results have been obtained in our system: dark current of 0.014 e-/s/pixel at
82K; readout noise of 23 e- for a single CDS pair and 5.4e- for a Fowler(32); a total electric power consumption of 203
mW in LVDS (excluding I/O power) mode.
The SIDECAR ASIC has also been characterized separately at room temperature. Two references voltages,
VPreAmpRef1 and VrefMain, used to adjust the offset of the pre-amp DAC has been studied. The reset voltage, Vreset,
was measured to have a root mean square stability of 22μV over 15 minutes and a root mean square stability value of 24μV over a 15 hours measurement period. An offset between set value and measured value of around 60mV for low set
voltages has been noticed. The behavior of VPreAmpRef1 and VrefMain with a adjustable external input voltage has
been conducted in order to tune these two biases to cover the desired input range with the best linearity.
Performance of the HgCdTe detector for MOSFIRE, an imager and multi-object spectrometer for Keck Observatory
Show abstract
MOSFIRE is a new multi-object near-infrared spectrometer for the Keck 1 telescope with a spectral resolving
power of R~3500 for a 0.7″ slit (2.9 pixels). The detector is a substrate-removed 2K × 2K HAWAII 2-RG HgCdTe
array from Teledyne Imaging Sensors with a cut-off wavelength of 2.5 μm and an operational temperature of
77K. Spectroscopy of faint objects sets the requirement for low dark current and low noise. MOSFIRE is also
an infrared camera with a 6.9′ field of view projected onto the detector with 0.18″ pixel sampling. Broad-band
imaging drives the requirement for 32-channel readout and MOSFIREs fast camera optics implies the need for
a very at detector. In this paper we report the final performance of the detector selected for MOSFIRE. The
array is operated using the SIDECAR ASIC chip inside the MOSFIRE dewar and v2.3 of the HxRG software.
Dark current plus instrument background is measured at <0.008 ē s−1 pixel−1 on average. Multiple Correlated
Double Sampling (MCDS) and Up-The-Ramp (UTR) sampling are both available. A read noise of <5ē rms is
achieved with MCDS 16 and the lowest noise of 3ē rms occurs for 64 samples. Charge persistence depends on
exposure level and shows a large gradient across this detector. However, the decay time constant is always ~660
seconds. Linearity and stability are also discussed.
NIRSpec detectors: noise properties and the effect of signal dependent inter-pixel crosstalk
Giovanna Giardino,
Marco Sirianni,
Stephan M. Birkmann,
et al.
Show abstract
NIRSpec (Near Infrared Spectrograph) is one of the four science instruments of the James Webb Space Telescope
(JWST) and its focal plane consists of two HAWAII-2RG sensors operating in the wavelength range 0.6−5.0μm.
As part of characterizing NIRSpec, we studied the noise properties of these detectors under dark and illuminated
conditions. Under dark conditions, and as already known, 1/f noise in the detector system produces somewhat
more noise than can be accounted for by a simple model that includes white read noise and shot noise on
integrated charge. More surprisingly, at high flux, we observe significantly lower total noise levels than expected.
We show this effect to be due to pixel-to-pixel correlations introduced by signal dependent inter-pixel crosstalk,
with an inter-pixel coupling factor, α, that ranges from ~ 0.01 for zero signal to ~ 0.03 close to saturation.
Posters-Monday
EMCCD camera noise performance for the Brazilian tunable filter imager
Show abstract
We present in this paper a performance characterization of an Electron Multiplication CCD (EMCCD) camera which has
been deployed on the Brazilian Tunable Filter Imager (BTFI) instrument for the SOAR telescope in Chile. The BTFI
instrument has two e2v CCD207 EMCCDs with a format of 1600-by-1600 pixels. The CCD207s are full-frame devices
and are read out at a pixel rate of 10MHz with very low noise using an EMCCD controller (the CCD Controller for
Counting Photons or CCCP for short) which was custom-built by a group based in the University of Montreal and is now
commercialized by Nüvü Camēras. The first laboratory characterizations were done in Montreal in October, 2011 and the
"first-light" results with the camera operating at the telescope are presented.
First results from a novel curving process for large area scientific imagers
Show abstract
Observations in seeing limited imaging conditions with an extremely large telescope - such as the European Extremely
Large Telescope (E-ELT) - will require large detectors and very fast cameras (around F/1.0). The correction of field
curvature is a complex task, requiring numerous optical elements operating with high incidence angles. Large format (60
to 90 mm square) concave detectors with a curvature radius between 500 and 250 mm would considerably simplify the
optical design, while improving image quality and cutting cost of optical components. Potential applications are not
limited to astronomy exclusively. The associated advantages of curved image sensors inside (mosaicked) focal planes
have been described in our paper “The challenge of highly curved monolithic imaging detectors”, presented at SPIE
2010 [1].
This paper compares in a first step important developments in the area of curving CCD and CMOS detectors using
different technical approaches linked to specific thinning processes with a novel approach followed after ESO’s initial
feasibility study: First results of the latter are described with a report on the chosen curving technology aimed at
producing 500 to 250 mm radius of curvature silicon detectors of approximately 60 mm square format (typical
astronomical 4k × 4k CCDs). The curvature technique has been developed for front-illuminated devices with the goal of
extending the process to back-illuminated sensors in the near future. We will discuss the fabrication process of curving
the devices as well as the difficulties encountered during development. Characterization results from a curved detector,
including metrology, and electrical performance before and after curvature are presented.
Hyper Suprime-Cam: characteristics of 116 fully depleted back-illuminated CCDs
Show abstract
Hyper Suprime-Cam (HSC)1,2 is a wide field imaging camera with the field of view (FOV) 1.5 degree diameter, which is to be installed at the prime focus of the Subaru Telescope. The large FOV is realized by the 116 2K × 4K pixels fully depleted back-illuminated CCD (FDCCD) with 15 μm pixel square. The acceptance inspection of the CCDs started around the end of 2009 and finished June 2011. We measured basic characteristics such as charge transfer efficiency (CTE), dark current, readout noise, linearity and the number of the dead column for all CCDs, and measured the quantum effciency (QE) of 21 CCDs. As a result, we confirmed exceptional quality and performance fdor all CCDs ans were able to select the best pissible 116 CCDs. We also measured the flatness of each CCD at room temperature, and optimally placed them on the focal plane plate. In this paper, we report the results of the acceptance inspection asn the installation process into the HSC dewar3,4.
Deep-depletion Hamamatsu CCDs for the Gemini Multi-Object Spectrograph
Show abstract
The instrumentation group of the Herzberg Institute of Astrophysics was commissioned by the Gemini Observatory to
develop a new focal plane assembly for the Gemini Multi-Object Spectrograph with an array of three deep-depletion
Hamamatsu CCDs. The main objective of the upgrade is to improve the sensitivity of the instrument in the red and nearinfrared
wavelengths, with the additional benefits of reduced fringing, faster readout, and better performance in the "nod
and shuffle" mode. We describe what we learned about these relatively new CCDs, including several problems
encountered during testing, and report on the performance of the system.
ESA's CCD test bench for the Euclid visible channel
Show abstract
The visual imaging instrument VIS on board Euclid baselines 36 newly designed CCD273-84 devices from e2v.
While these new devices have a 4kx4k format with four readout nodes, the Euclid Imaging Consortium (EIC) has
performed extensive test campaigns on both irradiated and un-irradiated devices of the 4kx1k Euclid precursor variant
CCD204-22. In support of the CCD development and characterization, and to enable an independent assessment of the
Euclid CCDs (the procurement of which is ESA’s responsibility), ESA/ESTEC has built a test bench. This test bench
allows for a flexible operation and readout of the CCDs, originally for CCD204 and shortly also for CCD273-84. It
provides the basic tools for noise and gain calibration, and CTI, QE, MTF and PRNU measurements. In addition, the
bench provides scanning spot illumination with a spot size well below the pixel size, for measurement of the intra-pixel
response of the CCDs before and after radiation damage. Such measurements are of great importance for the
characterization and modeling of the VIS instrument’s PSF, in particular to enable the prediction of the evolution of the
PSF shape under the influence of the L2 radiation environment during the mission. This set-up will also allow for
simulation of typical Euclid sky images in the lab. The capabilities and validation of this bench at ESA are described in
this paper.
Preliminary results of CCD characterisation at ESA in support of the Euclid visible channel
Show abstract
Euclid is the ESA mission to map the geometry of the dark Universe using two cosmological probes, namely Weak
Lensing and Baryonic Acoustic oscillations. The visual imager, a CCD based optical imaging channel will be used to
measure the shapes of galaxies in one single wide visual band spanning the wavelength range of 550-920 nm. The focal
plane array supports 36 CCDs (4k×4k pixels each) with 0.101 arcsec pixel platescale, giving a geometric field of 0.55
deg2. With the weak lensing technique, the mass distribution of the lensing structures can be traced back.
The originally baselined CCDs were e2v CCD203-82. Following the results from a dedicated radiation damage test
activity on their CCD204 variant, a new version, called 273 has been designed and made available in a front-illuminated
version in April 2012.
For Euclid, the accuracy with which the shape of the galaxies has to be measured is considerable: 1% and has never been
demonstrated. The radiation damage effects will adversely affect this measurement and thus need to be characterized.
Therefore, several test campaigns on the characterization of the CCD radiation damages for Euclid are carried out by
ESA and by the Euclid Imaging Consortium.
For this purpose, a test bench has been implemented at ESTEC to characterize CCD devices, with radiometric
measurements, point source illumination and lab simulation of typical Euclid sky images. The preliminary results
obtained at ESA on a non-irradiated front-illuminated Euclid prototype CCD 273-84-2-F16 will be shown in this article.
An advanced CCD emulator with 32MB image memory
Show abstract
As part of the LSST sensor development program we have developed an advanced CCD emulator for testing new
multichannel readout electronics. The emulator, based on an Altera Stratix II FPGA for timing and control, produces 4
channels of simulated video waveforms in response to an appropriate sequence of horizontal and vertical clocks. It
features 40MHz, 16-bit DACs for reset and video generation, 32MB of image memory for storage of arbitrary grayscale
bitmaps, and provision to simulate reset and clock feedthrough ("glitches") on the video channels. Clock inputs are
qualified for proper sequences and levels before video output is generated. Binning, region of interest, and reverse clock
sequences are correctly recognized and appropriate video output will be produced. Clock transitions are timestamped
and can be played back to a control PC.
A simplified user interface is provided via a daughter card having an ARM M3 Cortex microprocessor and miniature
color LCD display and joystick. The user can select video modes from stored bitmap images, or flat, gradient, bar, chirp,
or checkerboard test patterns; set clock thresholds and video output levels; and set row/column formats for image
outputs. Multiple emulators can be operated in parallel to simulate complex CCDs or CCD arrays.
PAU camera: detectors characterization
Show abstract
The PAU Camera (PAUCam) [1,2] is a wide field camera that will be mounted at the corrected prime focus of the
William Herschel Telescope (Observatorio del Roque de los Muchachos, Canary Islands, Spain) in the next months.
The focal plane of PAUCam is composed by a mosaic of 18 CCD detectors of 2,048 x 4,176 pixels each one with a pixel
size of 15 microns, manufactured by Hamamatsu Photonics K. K. This mosaic covers a field of view (FoV) of 60 arcmin
(minutes of arc), 40 of them are unvignetted.
The behaviour of these 18 devices, plus four spares, and their electronic response should be characterized and optimized
for the use in PAUCam. This job is being carried out in the laboratories of the ICE/IFAE and the CIEMAT.
The electronic optimization of the CCD detectors is being carried out by means of an OG (Output Gate) scan and
maximizing it CTE (Charge Transfer Efficiency) while the read-out noise is minimized.
The device characterization itself is obtained with different tests. The photon transfer curve (PTC) that allows to obtain
the electronic gain, the linearity vs. light stimulus, the full-well capacity and the cosmetic defects. The read-out noise, the
dark current, the stability vs. temperature and the light remanence.
Performance characterization of the near infrared detector system for RSS-NIR on SALT
Show abstract
We report on the status of the detector system for the Robert Stobie Spectrograph Near Infrared Arm (RSS-NIR) for the
Southern African Large Telescope (SALT). The detector is a HAWAII-2RG array with a 1.7 μm cutoff wavelength.
The controller incorporates a Teledyne cryogenic SIDECAR ASIC board inside the dewar and an FPGA interface card,
developed by the Inter-University Centre for Astronomy and Astrophysics (IUCAA), outside the dewar. Data
acquisition software written by IUCAA runs under a Linux operating system and communicates to the detector system
through USB to fiber optic converters for electrical isolation on the telescope. System characterization is performed at
the University of Wisconsin RSS-NIR Lab in a liquid nitrogen cooled test dewar. The test dewar contains a thermal
control system that emulates operation of the cryocooler used in the instrument dewar and maintains a stable detector
operating temperature of 120 K. Light is provided to the detector with near infrared LEDs mounted inside the dewar.
We present preliminary data on system noise and plans for further characterization tests.
Scientific CCD characterisation at Universidad Complutense LICA Laboratory
Show abstract
A CCD test-bench has been built at the Universidad Complutense´s LICA laboratory. It is initially intended for
commissioning of the MEGARA1 (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) instrument but
can be considered as a general purpose scientific CCD test-bench. The test-bench uses an incandescent broad-band light
source in combination with a monochromator and two filter wheels to provide programmable narrow-band illumination
across the visible band. Light from the monochromator can be directed to an integrating sphere for flat-field
measurements or sent via a small aperture directly onto the CCD under test for high accuracy diode-mode quantum
efficiency measurements. Point spread function measurements can also be performed by interposing additional optics
between sphere and the CCD under test. The whole system is under LabView control via a clickable GUI. Automated
measurement scans of quantum efficiency can be performed requiring only that the user replace the CCD under test with
a calibrated photodiode after each measurement run. A 20cm diameter cryostat with a 10cm window and Brooks
Polycold PCC closed-cycle cooler also form part of the test-bench. This cryostat is large enough to accommodate almost
all scientific CCD formats has initially been used to house an E2V CCD230 in order to fully prove the test-bench
functionality. This device is read-out using an Astronomical Research Camera controller connected to the UKATC´s
UCAM data acquisition system.
Test set up description and performances for HAWAII-2RG detector characterization at ESTEC
Show abstract
In the frame work of the European Space Agency's Cosmic Vision program, the Euclid mission has the objective to map
the geometry of the Dark Universe. Galaxies and clusters of galaxies will be observed in the visible and near-infrared
wavelengths by an imaging and spectroscopic channel.
For the Near Infrared Spectrometer instrument (NISP), the state-of-the-art HAWAII-2RG detectors will be used,
associated with the SIDECAR ASIC readout electronic which will perform the image frame acquisitions.
To characterize and validate the performance of these detectors, a test bench has been designed, tested and validated.
This publication describes the pre-tests performed to build the set up dedicated to dark current measurements and tests
requiring reasonably uniform light levels (such as for conversion gain measurements). Successful cryogenic and vacuum
tests on commercial LEDs and photodiodes are shown. An optimized feed through in stainless steel with a V-groove to
pot the flex cable connecting the SIDECAR ASIC to the room temperature board (JADE2) has been designed and tested.
The test set up for quantum efficiency measurements consisting of a lamp, a monochromator, an integrating sphere and
set of cold filters, and which is currently under construction will ensure a uniform illumination across the detector with
variations lower than 2%.
A dedicated spot projector for intra-pixel measurements has been designed and built to reach a spot diameter of 5 μm at
920nm with 2nm of bandwidth [1].
Standard modes of MPIA's current H2/H2RG-readout systems
Clemens Storz,
Vianak Naranjo,
Ulrich Mall,
et al.
Show abstract
Even though the last instruments built with the previous generation of MPIA-ROE are offering in the meantime most of
the standard readout modes, the current generation ROE is based on the experience of the last years, and besides other
properties like small volume, more channels, less power consumption, etc., it will also allow extended readout modes in
the near future by using the detector engineering and data interfaces of GEIRS.
The Hawaii-2-RG detector has a large amount of operational flexibilities to support extended readout modes. With
special properties in the pattern generator of the ROE and in GEIRS, new extended readout modes can be implemented
identically for the Hawaii-2 and the Hawaii-2RG in multichannel mode.
This paper presents an overview of the standard readout schemes and describes additional selectable options, offered
idle-modes, and some new extended modes available with this generation of MPIA-ROE for the next instruments and
instrument updates using HgCdTe-detectors.
During the last 15 years MPIA has built 8 sets of previous readout electronics (ROE) for 8 astronomical infrared
instruments1-8. The generic infrared camera software GEIRS (spoken like 'cheers') is used in these instruments either as a
pure readout software layer or as an overall control software for IR-instruments, the last case in particular with
instruments for the Calar-Alto observatory in Spain.
Investigation of linear-mode photon-counting HgCdTe APDs for astronomical observations.
Show abstract
The unique linear avalanche properties of HgCdTe preserve the Poisson statistics of the incoming photons, opening up
new opportunities for GHz bandwidth LADAR and space communications applications. Raytheon has developed and
previously reported (1) unique linear mode photon counting arrays based on combining advanced HgCdTe linear mode
APDs with their high gain SB415B readout. Their use of HgCdTe APDs preserves the Poisson statistics of the incoming
photons, enabling (noiseless) photon counting. This technology is of great potential interest to infrared astronomy but
requires extension of noiseless linear HgCdTe avalanching down to much lower bandwidths (100 to 0.001 Hz) with
corresponding reductions in dark count rate.
We have hybridized the SB415B readout to SWIR HgCdTe APDs optimized for low dark count rate and have
characterized their photon counting properties at bandwidths down to 1 KHz. As bandwidth is reduced, the performance
becomes limited by the intrinsic properties of the SB415B readout, particularly readout glow, stability and 1/f noise.
We report the results of these measurements and the status of hybrid arrays utilizing a newly developed readout which
draws on Raytheon’s astronomical readout heritage, specifically the Virgo charge integrating source follower, as a path
to much lower dark count rate photon counting operation.
Ultra-low noise large-area InGaAs quad photoreceiver with low crosstalk for laser interferometry space antenna
Show abstract
Quad photoreceivers, namely a 2 x 2 array of p-i-n photodiodes followed by a transimpedance amplifier (TIA) per diode,
are required as the front-end photonic sensors in several applications relying on free-space propagation with position and
direction sensing capability, such as long baseline interferometry, free-space optical communication, and biomedical
imaging. It is desirable to increase the active area of quad photoreceivers (and photodiodes) to enhance the link gain,
and therefore sensitivity, of the system. However, the resulting increase in the photodiode capacitance reduces the
photoreceiver's bandwidth and adds to the excess system noise. As a result, the noise performance of the front-end quad
photoreceiver has a direct impact on the sensitivity of the overall system. One such particularly challenging application
is the space-based detection of gravitational waves by measuring distance at 1064 nm wavelength with ~ 10 pm/√Hz
accuracy over a baseline of millions of kilometers.
We present a 1 mm diameter quad photoreceiver having an equivalent input current noise density of < 1.7 pA/√Hz per
quadrant in 2 MHz to 20 MHz frequency range. This performance is primarily enabled by a rad-hard-by-design dualdepletion
region InGaAs quad photodiode having 2.5 pF capacitance per quadrant. Moreover, the quad photoreceiver
demonstrates a crosstalk of < -45 dB between the neighboring quadrants, which ensures an uncorrected direction sensing
resolution of < 50 nrad. The sources of this primarily capacitive crosstalk are presented.
Enabling large focal plane arrays through mosaic hybridization
Show abstract
We have demonstrated advances in mosaic hybridization that will enable very large format far-infrared detectors.
Specifically we have produced electrical detector models via mosaic hybridization yielding superconducting circuit paths
by hybridizing separately fabricated sub-units onto a single detector unit. The detector model was made on a 100mm
diameter wafer while four model readout quadrant chips were made from a separate 100mm wafer. The individually
fabricated parts were hybridized using a flip-chip bonder to assemble the detector-readout stack. Once all of the
hybridized readouts were in place, a single, large and thick silicon substrate was placed on the stack and attached with
permanent epoxy to provide strength and a Coefficient of Thermal Expansion match to the silicon components
underneath. Wirebond pads on the readout chips connect circuits to warm readout electronics; and were used to validate
the successful superconducting electrical interconnection of the model mosaic-hybrid detector. This demonstration is
directly scalable to 150 mm diameter wafers, enabling pixel areas over ten times the area currently available.
EMIR high-dynamic range readout modes
Show abstract
EMIR is the NIR imager and multiobject spectrograph being built as a common user instrument for the GTC and it is
currently entering in the integration and verification phase at system level. EMIR is being built by a Consortium of
Spanish and French institutes led by the IAC.
In this paper we describe the readout modes of EMIR detector, a Hawaii2 FPA, after two full calibrations campaigns.
Besides the standard set of modes (reset-read, CDS, Fowler, Follow-up the ramp), the modified SDSU-III hardware and
home made software will also offer high dynamic range readout modes, which will improve the ability of the instrument
to sound densely populated areas which often are made of objects with large differences in brightness. These new high
dynamic range modes are: single readout with very short integration time, window mode and combination of both. The
results show that the new modes behave linearly with different exposition times, improve the maximum frame rate and
increase the saturation limit in image mode for EMIR instrument.
X-ray performance of e2v’s 0.18 µm CMOS APS test arrays for solar observation
Show abstract
Solar-C is the third generation solar observatory led by JAXA. The accepted ‘Plan-B’ payload calls for a radiation-hard
solar-staring photon-counting x-ray spectrometer. CMOS APS technology offers advantages over CCDs for such an
application such as increased radiation hardness and high frame rate (instrument target of 1000 fps). Looking towards the
solution of a bespoke CMOS APS, this paper reports the x-ray spectroscopy performance, concentrating on charge
collection efficiency and split event analysis, of two baseline e2v CMOS APSs not designed for x-ray performance, the
EV76C454 and the Ocean Colour Imager (OCI) test array. The EV76C454 is an industrial 5T APS designed for machine
vision, available back and front illuminated. The OCI test arrays have varying pixel design across the chips, but are 4T,
back illuminated and have thin low-resistivity and thick high-resistivity variants. The OCI test arrays’ pixel variants
allow understanding of how pixel design can affect x-ray performance.
Experimental measurements of charge carrier mobility: lifetime products for large sample of pixilated CZT detectors
Show abstract
Cadmium-Zinc-Telluride (CZT) is thought to be a primary work horse for hard X-ray astronomy in future.
Due to the relatively large band-gap, it offers near room temperature operation while maintaining much
better energy resolution then scintillator detectors operating in similar energy range. Further, CZT detectors
are available in the form of pixilated detectors with area up to few cm2 and hence it is possible to realize
very large detector area by having an array of such pixilated CZT detectors. However, it is well known that
the energy spectrum of mono-energetic X-ray measured by CZT detectors does not have a Gaussian shape
but has significant low-energy tail. This is mainly due to relatively poor mobility and small life time of the
charge carriers, particularly of holes, in the CZT crystals. Thus, in order to understand spectral response for
a large array of CZT detectors consisting of multiple elements / pixels, it is essential to characterize the
mobility-lifetime products of charge carriers for each individual elements / pixels. Here we present
experimental measurements of charge carrier mobility-lifetime products for large sample of multi-pixel
CZT detectors. The mobility-lifetime products are measured by simultaneously fitting a ‘CZT line’ model
to pixel wise spectra of 122 keV X-rays from 57Co at three different bias voltages. These were carried out
as a part of selection of CZT detector modules for the “High Energy X-ray spectrometer (HEX)” onboard
Indian moon mission – Chandrayaan-1.
Modeling charge transport in swept charge devices for X-ray spectroscopy
Show abstract
We present the formulation of an analytical model which simulates charge transport in Swept Charge Devices
(SCDs) to understand the nature of the spectral redistribution function (SRF). We attempt to construct the
energy-dependent and position dependent SRF by modeling the photon interaction, charge cloud generation and
various loss mechanisms viz., recombination, partial charge collection and split events. The model will help in
optimizing event selection, maximize event recovery and improve spectral modeling for Chandrayaan-2 (slated
for launch in 2014). A proto-type physical model is developed and the algorithm along with its results are
discussed in this paper.
High-resolution gamma-ray detection using phonon-mediated detectors
Show abstract
We are presenting the results of our ongoing efforts to develop a new type of focal plane detector for the 10 to 100
keV band with an energy resolution of 0.1 %. The device will measure energy and position by using microwave
kinetic inductance detectors (MKIDs) to sense athermal phonons created by photon absorption in a dielectric
substrate. We have fabricated a proof-of-concept detector of size 2 cm × 2 cm × 1 mm on silicon, which has
demonstrated a baseline energy resolution of = 0.38 keV and = 0.55 keV at 30 keV.
Circuit design of an EMCCD camera
Show abstract
EMCCDs have been used in the astronomical observations in many ways. Recently we develop a camera using an
EMCCD TX285. The CCD chip is cooled to −100°C in an LN2 dewar. The camera controller consists of a driving board,
a control board and a temperature control board. Power supplies and driving clocks of the CCD are provided by the
driving board, the timing generator is located in the control board. The timing generator and an embedded Nios II CPU
are implemented in an FPGA. Moreover the ADC and the data transfer circuit are also in the control board, and
controlled by the FPGA. The data transfer between the image workstation and the camera is done through a Camera Link
frame grabber. The software of image acquisition is built using VC++ and Sapera LT. This paper describes the camera
structure, the main components and circuit design for video signal processing channel, clock driver, FPGA and Camera
Link interfaces, temperature metering and control system. Some testing results are presented.
Architecture of PAU survey camera readout electronics
Show abstract
PAUCam is a new camera for studying the physics of the accelerating universe. The camera will consist of eighteen
2Kx4K HPK CCDs: sixteen for science and two for guiding. The camera will be installed at the prime focus of the WHT
(William Herschel Telescope). In this contribution, the architecture of the readout electronics system is presented. Back-
End and Front-End electronics are described. Back-End consists of clock, bias and video processing boards, mounted on
Monsoon crates. The Front-End is based on patch panel boards. These boards are plugged outside the camera feed-through
panel for signal distribution. Inside the camera, individual preamplifier boards plus kapton cable completes the
path to connect to each CCD. The overall signal distribution and grounding scheme is shown in this paper.
The Dark Energy Camera readout system
Show abstract
The Dark Energy Camera (DECam) was developed for use by the Dark Energy Survey (DES). The camera will be
installed in the Blanco 4M telescope at the Cerro Tololo Inter-American Observatory (CTIO) and be ready for
observations in the second half of 2012. The focal plane consists of 62 2×4K and 12 2×2K fully depleted CCDs. The
camera provides a 3 sq. degree view and the survey will cover a 5000 sq. degree area. The camera cage and corrector
have already been installed.
The development of the electronics to readout the focal plane was a collaborative effort by multiple institutions in the
United States and in Spain. The goal of the electronics is to provide readout at 250 kpixels/second with less than 15erms
noise. Integration of these efforts and initial testing took place at Fermi National Accelerator Laboratory. DECam
currently resides at CTIO and further testing has occurred in the Coudé room of the Blanco. In this paper, we describe
the development of the readout system, test results and the lessons learned.
Hyper Suprime-Cam: performance of the CCD readout electronics
Show abstract
Hyper Suprime-Cam (HSC) employs 116 pieces of 2k×4k fully-depleted CCD with a total of 464 signal outputs to cover
the 1.5 degrees diameter field of view. The readout electronics was designed to achieve ~5 e of the readout noise and
150000 e of the fullwell capacity with 20 seconds readout time. Although the image size exceeds 2G Bytes, the readout
electronics supports the 10 seconds readout time for the entire CCDs continuously. All of the readout electronics and the
CCDs have already been installed in the camera dewar. The camera has been built with equipment such as coolers and an
ion pump. We report the readout performance of all channels of the electronics extracted from the recent test data.
Software solution for autonomous observations with H2RG detectors and SIDECAR ASICs for the RATIR camera
Show abstract
The Reionization And Transients InfraRed (RATIR) camera has been built for rapid Gamma-Ray Burst (GRB)
followup and will provide quasi-simultaneous imaging in ugriZY JH. The optical component uses two 2048 × 2048
pixel Finger Lakes Imaging ProLine detectors, one optimized for the SDSS u, g, and r bands and one optimized
for the SDSS i band. The infrared portion incorporates two 2048 × 2048 pixel Teledyne HgCdTe HAWAII-2RG
detectors, one with a 1.7-micron cutoff and one with a 2.5-micron cutoff. The infrared detectors are controlled by
Teledyne's SIDECAR (System for Image Digitization Enhancement Control And Retrieval) ASICs (Application
Specific Integrated Circuits). While other ground-based systems have used the SIDECAR before, this system
also utilizes Teledyne's JADE2 (JWST ASIC Drive Electronics) interface card and IDE (Integrated Development
Environment). Here we present a summary of the software developed to interface the RATIR detectors with
Remote Telescope System, 2nd Version (RTS2) software. RTS2 is an integrated open source package for remote
observatory control under the Linux operating system and will autonomously coordinate observatory dome,
telescope pointing, detector, filter wheel, focus stage, and dewar vacuum compressor operations. Where necessary
we have developed custom interfaces between RTS2 and RATIR hardware, most notably for cryogenic focus stage
motor drivers and temperature controllers. All detector and hardware interface software developed for RATIR
is freely available and open source as part of the RTS2 distribution.
Performances and results of the detector acquisition system of the GIANO spectrometer
Show abstract
GIANO is a high resolution (R≃50,000) cryogenic IR spectrograph covering the 0.95-2.5μm wavelengths range.
It is equipped with a Hawaii-II PACE array. We present the main results and performances of the detector and
acquisition system. We also describe a few special features which have been developed to optimize the noise
performances and minimize spurious effects intrinsic to the detector, such as reset anomaly, cross-talking and
radioactive-like events.
A simple controller for bidimensional image detectors
Show abstract
The increasing use of many and different kind of light detectors to acquire, monitor and control various
aspects of the observation imposes the need to standardize the acquisition and processing of images and data. While
scientific image acquisition systems usually include a complex controller, some less demanding subsystems require
the development of electronics and software to read the image. Most of the times these image detectors are rather
small and high speed is of no concern, so controllers need not to be fast; take for instance a telescope guider. With
these directives in mind, in this work we present a very simple image acquisition system based on a Texas
Instruments microcontroller of the family MSP430 and a serial static memory as a standard instrumentation starting
for small image acquisition controllers.
Comparison of hybrid and SIDECAR ASIC measurements
Show abstract
The readout noise of a H2RG HgCdTe NIR detector from Teledyne is measured at a temperature T=100K.
In a previous work, we have analysed the evolution of the readout noise as a function of the number of reads
in terms of the frequency power spectrum of the noise with our in-house hybrid readout electronics. The new
measurements with the SIDECAR ASIC provided by Teledyne Imaging Sensors are compared to the previous
ones. The noise power spectrum found can be used in a wide range of timing conditions and allows to predict
the 1/f effects.
The low Earth orbit radiation environment and its impact on the prompt background of hard x-ray focusing telescopes
Show abstract
The background minimization is a science-driven necessity in order to reach deep sensitivity levels in the hard
X-ray band, one of the key scientific requirements for hard X-ray telescopes (e.g. NuSTAR, ASTRO-H). It
requires a careful modeling of the radiation environment and new concepts of shielding systems. We exploit
the Bologna Geant4 Multi-Mission Simulator (BoGEMMS) features to evaluate the impact of the Low Earth
Orbit (LEO) radiation environment on the prompt background level for a hybrid Si/CdTe soft and hard X-ray
detection assembly and a combined active and passive shielding system. For each class of particles, the spectral
distribution of the background flux is simulated, exploring the effect of different materials (plastic vs inorganic
active scintillator) and configurations (passive absorbers enclosing or surrounded by the active shielding) on
the background count rate. While protons are efficiently removed by the active shielding, an external passive
shielding causes the albedo electrons and positrons to be the primary source of background. Albedo neutrons
are instead weakly interactive with the active shielding, and they cause an intense background level below 10
keV via elastic scattering. The best shielding configuration in terms of background and active shielding count
rates is given by an inorganic scintillator placed inside the passive layers, with the addition of passive material
to absorb the intense fluorescence lines of the active shielding and avoid escape peaks on the CdTe detector.
The effects of radiation damage on the spectral resolution of the Chandrayaan-1 x-ray spectrometer over the full mission duration
Show abstract
The Chandrayaan-1 X-ray Spectrometer (C1XS) was launched onboard the Indian Space Research Organisation (ISRO)
Chandrayaan-1 lunar mission in October 2008. The instrument consisted of 24 swept-charge device silicon X-ray
detectors providing a total collecting area of ~24 cm2, corresponding to a 14° field of view (FWHM), with the ability to
measure X-rays from 0.8 – 10 keV. During the 10 months the spacecraft was located in orbit around the Moon a number
of solar flare X-ray events were detected, along with calibration data from X-ray sources housed inside the movable door
of the instrument. This paper presents a further study of the degradation in spectral resolution of the measured X-ray
calibration lines, adding a final calibration point towards the end of mission lifetime to the known results from the
midpoint of the mission, giving a more detailed analysis of the extent of the radiation damage. The radiation environment
the detectors were subjected to is discussed in light of the actual radiation damage effects on the spectral resolution
observed in flight.
A multiplexer for the AC/DC characterization of TES-based bolometers and microcalorimeters
Show abstract
At SRON we are developing the Frequency Domain Multiplexing (FDM) for the read-out of the TES-based
detector array for the future infrared and X-ray space mission. We describe the performances of a multiplexer
designed to increase the experimental throughput in the characterisation of ultra-low noise equivalent power
(NEP) TES bolometers and high energy resolving power X-ray microcalorimeters arrays under ac and dc bias.
We discuss the results obtained using the TiAu TES bolometers array fabricated at SRON with measured dark
NEP below 5 · 10−19W/
√
Hz and saturation power of several fW.
A system for the characterization of the HAWC PMTs sensitivity
R. Langarica,
G. Lara,
L. A. Martinez,
et al.
Show abstract
The HAWC Project is a very high-energy gamma-ray observatory under construction at the Sierra Negra volcano (4100
meters above sea level) in the Pico de Orizaba National Park located in central Mexico. HAWC will reuse the 900
Hamamatsu R5912 photomultipliers (PMTs) from Milagro Observatory for the 300 Water Cherenkov Detectors. In order
to characterize their present performance it is necessary to scan the active area of the photocathode by measuring its
efficiency and gain. A characterization system was designed and manufactured to achieve an automated measurement of
over 100 points distributed on the PMT active spherical surface. Preliminary results show the variation of QE of PMTs
with respect of the position of incoming photons, as well as the changes in the PMTs response due to the Earth's
magnetic field and gain vs. high voltage. The system allows automated PMT characterization improving its performance,
reliability, precision and repeatability. In this work we present the characterization system and preliminary results on the
PMT efficiency.
BoGEMMS: the Bologna Geant4 multi-mission simulator
Show abstract
BoGEMMS, (Bologna Geant4 Multi-Mission Simulator) is a software project for fast simulation of payload on board of
scientific satellites for prompt background evaluation that has been developed at the INAF/IASF Bologna. By exploiting
the Geant4 set of libraries, BoGEMMS allows to interactively set the geometrical and physical parameters (e.g. physics
list, materials and thicknesses), recording the interactions (e.g. energy deposit, position, interacting particle) in NASA
FITS and CERN root format output files and filtering the output as a real observation in space, to finally produce the
background detected count rate and spectra. Four different types of output can be produced by the BoGEMMS capturing
different aspects of the interactions. The simulator can also run in parallel jobs and store the results in a centralized
server via xrootd protocol. The BoGEMMS is a multi-mission tool, generally designed to be applied to any high-energy
mission for which the shielding and instruments performances analysis is required.
HST/WFC3 UVIS detectors: radiation damage effects and mitigation
Show abstract
Devices in low Earth orbit are particularly susceptible to the cumulative effects of radiation damage and the Hubble
Space Telescope Wide Field Camera 3 (HST/WFC3) UVIS detectors, installed on HST in May 2009, are no exception.
Such damage not only generates new hot pixels but also generates charge traps which degrade the charge transfer
efficiency (CTE), causing a loss in source flux as well as a systematic shift in the object centroid as the trapped charge is
slowly released during readout. Based on an analysis of internal and external monitoring data, we provide an overview
of the consequences of the ~3 years of radiation damage to the WFC3 CCD cameras. The advantages and disadvantages
of available mitigation options are discussed, including use of the WFC3 post-flash and charge injection modes now
available to observers, and the status of an empirical pixel-based correction similar to the one adopted for the HST
Advanced Camera for Surveys (ACS).