A Portable Beta Spectrometer/Dosimeter

As part of an ongoing program l,2 to upgrade health and safety radiation survey instruments, the Los Alamos National Laboratory has developed a portable, battery-operated, computerized beta spectrometer/ dosimeter. The instrument will support many different detectors, but the one chosen here is a combination plastic scintillator and NaI crystal. The instrument includes pulse conditioning circuits, 128-channel pulse height analyzer with integral liquid crystal display, and a microcomputer system which calculates dose and dose rate from betas incident on the detector. Instrument operating life is about 8 hours between charges. The instrument will, at the user's option, display a beta spectrum or the accumulated dose in millirad, as well as give the user beta dose rates in millirad per hour. (At this point, the dosimetry algorithms are still under development.) Data accumulated in the instrument can be read out through an RS-232 serial port on the instrument. The entire unit weighs 8 pounds, including internal batteries, and is packaged in a small case 25-cm long, 15-cm wide, and 15-cm high.