Photon Counting Detector Package Optimized For Space Debris Optical Tracking

The new photon counting detector package has been developed for applications of the orbiting space debris optical tracking. The advanced construction of the detector control electronics enables to operate the detection chip in continuous and gated photon counting operational modes. Using the proposed construction the detector is capable to monitor the strength of a solar radiation diffused reflected by the space debris. Combining the continuous and gated detection modes enables to measure the photon flux rates over more than three orders of magnitudes ranging from one kHz to several MHz. In addition, the gated mode is optimized for laser ranging of orbiting space debris. The two operation modes of the detector may be switched electronically. The detector is based on a commercial SAP500 avalanche photodiode detection chip with active area diameter of 500 mu m, which enables its simple integration into the large input aperture astronomical telescopes. The detection chip is operated at a fixed temperature of -8 degrees C. In a gated mode the photon detection efficiency exceeds 60% at 532 nm. Its timing resolution is typically better than 100 ps rms. In a continuous mode its dark count rate is well below 10 kHz. This detector package was developed as our contribution to the ESA activity "Space Situational Awareness program P2- SST-VII Expert Coordination Centre; Phase II".