Advanced Research Instruments Corp. has unveiled its Dual Precision Ratemeter/Photon Counter PRM-400. The device features a 500-MHz counter/timer ratemeter, a dual counter for background subtraction, large first in/first out data storage, zero dead time, 40-bit-deep counters and gated inputs. The device accepts standard TTL, NIM and ECL inputs. It also has a digital/bar graph intelligent LCD display; parallel, serial and GPIB computer interface; and simplified computer interfacing without plug-in boards. Besides photon counting, applications include ion, mass, electron and light spectroscopy, and surface analysis.