Characterizing the Speedster-EXD 550 X-ray Hybrid CMOS Detectors for the BlackCAT CubeSat

We report on the development of the Teledyne Imaging Systems X-ray hybrid CMOS detectors (HCD) that are capable of event-triggered read-out. HCDs have advantages over traditionally used CCDs including faster read-out times, reduced susceptibility to radiation damage, and lower power consumption. The Speedster-EXD has 40 μm pixel pitch and in-pixel circuitry that includes correlated double sampling to reduce signal readout chain noise, a CTIA amplifier to eliminate interpixel capacitance, and a comparator to flag X-ray events for read-out. The in-pixel comparator enables the detector to read out only those pixels associated with X-ray events, which allows the Speedsters to resolve event timing to as fine as 100 μs. The Speedster-EXD technology has been previously proven using 64×64 pixel prototypes and is now expanded to 550×550 pixel detectors. We have chosen to use four Speedster-EXD 550s as the focal plane array for the upcoming BlackCAT 6U CubeSat mission. The Speedster-EXD is also an excellent candidate for future X-ray missions requiring large format silicon imagers with high throughput and fast frame rates. Here we report on the latest Speedster-EXD 550 optimization, characterization, and performance, with emphasis on their use in the focal plane of BlackCAT.