AN SSPM-BASED HIGH-SPEED NEAR-INFRARED PHOTOMETER FOR ASTRONOMY

We describe the design, operation, and performance of a new high-speed infrared photometer using the Solid-State Photomultiplier (SSPM) dete ctor. The SSPM was developed by Rockwell International Science Center and has single-photon counting capability over the 0.4-28 mu m wavelen gth range, intrinsic time response of order 1 ns, and low detector noi se (Petroff et al. 1987, Appl. Phys. Lett., 51, 6). We have operated a 200X200 mu m back-illuminated SSPM in a liquid-helium cooled dewar wi th a room-temperature transimpedance amplifier output. Single photon p ulses can be easily distinguished above the amplifier noise. The indiv idual photon pulses are binned at a selectable time resolution ranging from 5 mu s to 64 ms, and then written to Exabyte tape. In the first astronomical application of such a device, we have made observations o f the Crab Nebula pulsar and Her X-1 at near-infrared wavelengths (J, H, and K bands), and we present the instrument sensitivities establish ed by these observations. We discuss other astronomical observations w hich are either planned or currently underway. Finally, we present des ign specifications and predicted performances for a second-generation SSPM high-speed infrared photometer.