SOPHIE (Solar Photometric Helium Imaging Experiment) is a design for a new space-borne EUV multi-layer reflecting coronagraph to obtain full coronal field-of-view (solar disk and 1.1 to 3.0 solar radii above the limb) observations in He II 304 angstrom, and to measure the coronal helium abundance as a function of structure and time in the corona. Knowledge of the coronal helium abundance is fundamental to understanding the dynamics of the solar wind acceleration region, yet its value is not well known. SOPHIE will open up a new observational domain by providing full field-of-view coronagraph observations of helium, as opposed to electrons observed with traditional white light coronagraphs. Moreover, it has been recognized in the last several years that time variable phenomena is important and relevant to every aspect of the transition region and corona.

Galmatheia is a proposed far-ultraviolet (FUV) 900 - 1850 angstrom imaging spectrograph optimized for the study of diffuse emission. Its spectra will be used to study hot galactic plasmas, characterize the formation/destruction cycle and distribution of H₂ in the ISM, and determine the optical properties of dust and its spatial distribution through the Galaxy. Galmatheia is a dual reflective spectrograph consisting of two elliptical diffraction gratings and a common cylindrical mirror, slit and detector. Its 5(sigma) sensitivity to C IV/O VI emission in a one-day pointing an order of magnitude fainter than any previous detection or to theoretical predictions.

The Ultraviolet Coronagraph Spectrometer (UVCS) of the Solar and Heliospheric (SOHO) mission has been developed for spectroscopic and polarimetric determinations of temperatures, densities and flow velocities in the extended solar corona. The instrument consists of a visible light (VL) polarimeter, and two ultraviolet (UV) spectrometers, optimized for the H I Lyman (alpha) (Ly-(alpha) ) line ((lambda) 1216 angstrom) and for the O VI doublet ((lambda) (lambda) 1032/1037 angstrom). The stray-light profile of the Ly-(alpha) holographic grating has been measured, in a laboratory set-up, in both the spatial and spectral directions. The observed profile has been found to be a combination of two components: the scattering from the grating surface, and the Fraunhofer diffraction due to the vignetting of the grating. An analytical expression for the scattering component of the grating point spread function (PSF) has been derived from a simple model of the grating surface roughness. The stray-light profile generated by the analytical expression of the grating PSF gives a good fit of stray-light profile measured in the laboratory. This instrument function has been used in the analysis of in-flight UVCS observations of the profile of electron scattered Ly- (alpha) from the solar corona. These observations have resulted, for the first time, in the most direct measurement of the coronal electron temperature.

The Naval Research Laboratory has built five ultraviolet spectrographs (SSULI) for the Air Force Defense Meteorological Satellite Program (DMSP). These sensors provide vertical intensity profiles of airglow emissions in the extreme and far ultraviolet spectral range of 800 to 1700 Angstrom and scan from 75 km to 750 km tangent altitude. A stacked grid collimator defines the 0.1 degree X 2.4 degree field-of- view of the sensor. The collimator is designed to cover the spectral range of the instrument and is optimized at 1000 angstrom. However, above 2000 angstrom, diffraction significantly reduces the collimator performance. Therefore, most characteristics of the collimator were previously measured in the UV. Recent theoretical work using Fourier optics to treat diffraction effects was used in the analysis of the performance of the collimators. Since transmission measurements are substantially easier and less expensive at visible wavelengths than in the vacuum ultraviolet, a technique was developed to adequately determine collimator performance in the UV from measurements in the visible. The performance of 3 SSULI collimators was evaluated at 2537 and 6328 angstrom. This paper presents a discussion of the results of the measured transmission and diffraction intensity patterns and their relationship to the theoretical predictions. Also presented is a description of techniques used to perform these measurements.

Chemically-vapor-deposited (CVD) silicon carbide (SiC) has become a popular mirror material for spaceborne solar instrumentation for the vacuum ultraviolet wavelength range due to its appreciable broadband reflectance and favorable thermal and opto-mechanical properties. Scatter from surfaces of mirrors operating in this wavelength range can destroy otherwise good image contrast especially for extended targets such as the sun. While valid far ultraviolet (FUV) scatter measurements are entirely non-trivial to conduct and so are rarely performed, visible light scatter measurements are comparatively easy. Unfortunately, it is not straightforward to predict FUV scatter performance based on visible light scatter measurements for mirrors made of CVD SiC. It is hoped that by carrying out scatter measurements in both wavelength regimes for the same CVD SiC mirror, that the ability to make such predictions may be enhanced. Visible light (633 nm) scatter measurements were performed at Goddard Space Flight Center (GSFC) by two different means on CVD SiC telescope mirrors (from the same process and same vendor) for two instruments on the Solar and Heliospheric Observatory (SOHO) - - the Ultraviolet Coronagraph Spectrometer (UVCS) and Solar Ultraviolet Measurement of Emitted Radiation (SUMER). Additionally, extensive FUV scatter measurements were made for SUMER telescope mirrors. In this paper, we correlate the results for those FUV and visible light scatter measurements for this important material.

A stigmatic spectrograph in the 17 - 23 nm region for observations of the solar disk and corona based on multilayer mirror and grating is described. Its main scientific use is global surveying of the disk with approximately equal 10 arcsec² resolution. Spectral resolution is used to monitor temperature- and density-sensitive spectral lines thus obtaining solar temperature and density maps in the 10⁵ - 10⁷ degrees Kelvin, 10¹³ - 10¹⁸ cm^-3 ranges, respectively. The use of off-axis paraboloidal telescope coupled with a toroidal grating results in spectral resolving powers of the order of 1000 and angular resolution of approximately equal 10 arcsec throughout an instantaneous field-of-view of 10 arcsec X 40 arcmin. Temporal resolution of the order of 0.1 second is expected which can be of use in observations of high brilliance events. The system is also equipped with a visible channel to correlate XUV events with ground observations.

An experiment is described which aims to determine the pion mass to 1 ppm or better, from which a new determination of the upper limit of the muon neutrino mass is anticipated. The approach utilizes spectroscopy of X-ray emissions from pionic atoms formed in gaseous targets. The spectroscopy is performed with a Bragg crystal spectrometer, with an energy resolution of approximately 300 meV, using an array of X-ray CCDs mounted at the focus to measure the spectral line structure of the 4 keV pionic nitrogen transition. To achieve sub-ppm accuracy, as energy calibration a muonic oxygen transition is used. It is known with a precision of 0.3 ppm and almost coincides in energy with the pionic transition.

The Instrumentation Program at Physics Department of the University of Nevada, Reno, USA is based on results of the development and study of one of first glass capillary optics devices in period from 1974 to earlier 90s in USSR/Russia (by V. Kantsyrev, O. Ananyin, Yu. Bykovsky and collaborators). The main direction of our program is the development of several techniques for extreme ultraviolet, soft x-ray and x-ray optical instrumentation, for spectroscopic diagnostics of hot plasmas, spectroscopic studies of interaction of multicharged ion beams with matter, biomedical x-ray microscopy. Our currently-developed instruments include: EUV polarimeter/spectrometer with GCC polarizing and focusing elements; a high resolution, a high-sensitivity EUV and x-ray spectrometer with focusing GCC, that also serves as a high- transmission window for differential vacuum pumping; a prototype of new multiband, two dimensional EUV and x-ray imaging spectrometer for plasma diagnostics; a pinhole camera with GCC using as a hard x-ray filter; a soft x-ray spectrograph with MLM for plasma diagnostics.

Frequently, EDS (Energy Dispersive Spectrometer) x-ray detectors cannot be placed very close to an x-ray source for microanalysis causing the detector to subtend a small solid angle thus reducing the available count rate. This is exacerbated by low count rates for the light elements and situations where low energy spectral lines are immersed in a background of higher energy x-rays from heavier elements. Larger detectors can be used at the expense of resolution but in many situations there is insufficient room for a large detector so a 10 mm² detector is used. Notch filters can sometimes be used to minimize higher energy counts but they do not allow a broad spectrum of low energy x-rays to pass and still allow passage of the highest energy x-rays to the detriment of light element detection. We have developed low energy x-ray optics which increase the solid angle seen by EDS detectors and can also act as low pass filters preferentially allowing passage of low energy x-rays. In a typical situation where 10 mm² detectors are used with a 35 mm distance between x-ray source and detector surface, our optics can provide a flux gain of about 22X for B (Boron) x-rays with gain decreasing toward unity at energy above O (Oxygen at 525 eV) with gain remaining at unity for higher energy. In other words, we greatly increase the performance at the lowest energies without affecting the higher energies.

A new method of X-ray polarimetry based on the photoeffect and measuring the photoelectron emission direction in a finely segmented MOS CCD has been established with monochromatic synchrotron radiation of known linear polarization. For square pixels of 6.8 micrometer an analyzing power in the order of 10% has been measured at energies above 10 keV. A steep rise with energy is observed in accord with Monte Carlo simulations. In addition to small charge deposits due to the photoeffect in the thin depleted front layer of the CCD, also diffusion spread charge clusters from the much more abundant conversions deeper inside the chip were found to be very useful for simultaneous measurements of the polarization vector, the energy and the position on a photon-by-photon basis. In a first application of spatially and energetically resolved polarimetry the linear polarization of Parametric X- radiation (PXR) produced by 80.5 MeV electrons in a 13 micrometer thick silicon single crystal has been analyzed. The experiment was carried out at the Darmstadt superconducting linear accelerator S-DALINAC providing a low-emittance electron beam. The linear polarization of the (220) reflex observed in 8 narrow angular bins between 20 degrees and 21 degrees with respect to the electron beam direction is consistent with complete local linear polarization. The orientation of the polarization plane, within measurement errors of typically 10 degrees, varies over the diffraction pattern in such a way as to be expected from kinematical theory. The result of this experiment is in contradiction to the only other PXR polarization measurement performed so far.

A soft X-ray ellipsometer using transmissive multilayer polarizers has been developed. It employs monochromatic 13-nm radiation from a synchrotron as a light source. Fifty free- standing pairs of semitransparent Mo/Si multilayers were used as a transmissive polarizer and as an analyzer. A fabricated polarizer functioned well both as a linear polarizer and as a phase retarder. It had a polarizance of 0.999 and a phase retardation of 90 degrees; and the relative transmittance was 0.785. Arranging two transmissive polarizers in the polarizer/compensator-sample-analyzer configuration enabled full control of the polarization of the probe beam. The modified polarization of light reflected from a sample was analyzed by the rotating-analyzer ellipsometry method. This system was applied to measurements on Silicon on insulator (SOI) substrates with an ultrathin superficial Si layer. We verified that there was a large change in the ellipsometric angles in the interference region. A soft X-ray ellipsometer is a very promising tool for thickness measurements on SOI substrates because of its high sensitivity to the thickness of the superficial Si layer and its insensitivity to the thickness of the buried SiO2 layer.

A novel diffraction spectroscopic instrument consisting of a large area transmission grating and a grazing-incidence pre- optics comprising of a toroidal mirror, a slit and a cylindrical mirror has been implemented. A nearly perfect stigmatism and a medium spectral resolution are due to the separation of the focusing and dispersing function. The experimental results show that it is possible to construct large area transmission grating spectrograph with high collecting efficiency and good spatial resolution.

It is known that all changes in state of polarization of EM radiation taken place without depolarization can be completely described by means of deterministic Mueller matrix. Such a 4 X 4 matrix transforms Stokes vector of incident radiation and can be expressed in terms of correspondent 2 X 2 Jones matrix. Lately relations between the two types of matrix are obtained. In the same time physically acceptable nondepolarizing Mueller matrix can have no correspondent Jones matrix. Such situation can take place when Mueller matrix is a nondepolarizing but not a deterministic. It is shown that conditions of nondepolarization are more soft then deterministic ones and, thus, deterministic Mueller matrix is a subset of nondepolarizing one. The minimum set of nondepolarizing conditions is obtained.

Lately definite efforts were undertaken in the field of elucidation of physical meaning and terminology conformity: depolarizing, nondepolarizing, deterministic, and nondeterministic systems. In spite of that this problem do not completely solve yet. In particular, a result issued from such situation is an existence of surprising assertion that system polarization properties of which are determined by Mueller- Jones (i.e. deterministic one) matrix can depolarize incident radiation. In this paper the detail analysis of the situation was conducted. On basis of this analysis new physically nondiscrepant and clear classification of systems 'polarization behavior' is presented.

A portable, pulsed digital x-ray imaging device has been developed. The system is intended to be used in explosive ordnance disposal, police and customs baggage inspection and nondestructive testing (NDT). The x-ray source is a portable flash x-ray source. Image acquisition is performed by a charge-coupled-device (CCD) imaging sensors which view the output of a x-ray scintillation screen via an optical system. The construction of the system, its specifications, and its test results are presented. In addition, we study the signal- to-noise ratio, lesion detectability and detective quantum efficiency of the system, and obtain the main factors affecting the performance of the system. This study may help us designing and evaluating optically-coupled CCD x-ray imaging systems effectively.

Low-debris laser-produced plasma is a much better soft x-ray source than conventional metal target laser plasma in many applications. We present a cryogenic target low-debris laser plasma source and give its experimental results in this paper.

We have developed a new type of X-Ray spectrometer intended for light element micro-analysis applications. This spectrometer typically has energy resolution better than 20 eV, very high count rates for low X-Ray energies characteristic of light elements, quasi-parallel data collection similar to Energy Dispersive Spectroscopy (EDS), weighs less than 20 lb., and is mechanically very simple. Fabrication of this spectrometer is possible due to our development of X-Ray collection/collimation optics for low X- Ray energy which collect large solid angles of sub-KeV x-rays and reflect them into a parallel beam. The spectrometer is intended for electron beam microanalysis, small spot XRF and other X-Ray micro-analysis methods. In this paper, we present the theory of operation, some details of collimator fabrication, spectrometer fabrication and some preliminary test data.

During the late stages of integration at MATRA-Marconi in Toulouse, France of the Ultraviolet Coronagraph Spectrometer (UVCS) for the joint NASA/ESA (European Space Agency) Solar and Heliospheric Observatory (SOHO), project management for the International Solar and Terrestrial Physics Project (ISTP) at Goddard Space Flight Center (GSFC) became concerned that the instrument's elaborate stray light rejection system had not been tested and might possibly be misaligned such that the instrument could not deliver promised scientific returns. A white light stray light test, which would place an upper bound on UVCS's stray light rejection capability, was commissioned, conceived, and carried out. This upper bound value would be indicative of the weakest coronal features the spectrometer would be capable of discerning. The test was rapidly developed at GSFC, in parallel with spacecraft integration, in coordination with science team members from Harvard- Smithsonian Center for Astrophysics (CFA) and was carried out at MATRA in late February 1995. The outcome of this test helped justify later impact to integration schedule to conduct similar much needed testing with visible and far ultraviolet light at CFA in a facility specifically designed to perform such tests.