Transition-edge sensor time-division multiplexing (TDM) digital readout electronics for the Line Emission Mapper (LEM)

We are developping space-qualified room-temperature digital readout electronics for the Line Emission Mapper (LEM) mission. LEM is a concept for a NASA X-ray probe designed for imaging and spectroscopy of large area low surface brightness X-ray emissions in the 0.2 to 2 keV range. The main detector is a hybrid transition-edge sensor (TES) array with a 30' x 30' outer array consisting of 2x2 Hydra 12,736 square pixels with a grid of 290 um and a 7' x 7' inner subarray consisting of 784 square pixels arranged in the center of the outer array with the same pixel pitch. The baselined readout technology for the total of 3,968 TES sensors is time-division multiplexing (TDM), which divides the sensors into 69 columns and 60 rows. At GSFC, we have developed a TRL-6 prototype of the room-temperature digital readout electronics and demonstrated a 2 eV full-width half-maximum at 6 keV for a 60-pixel co-added spectrum in a 2x32 TDM readout on the Athena-like TES array. In this presentation we show the count-rate capabilities of the readout electronics for a LEM-like hybrid TES array.