Year
1967
Abstract
A compact, portable gamma spectrometer was developed for use by the United States Atomic Energy Commission Division of International Affairs in safeguard- 235 ing inventories of U contained in nuclear reactor unirradiated fuel elements or in various other sources. General purpose gamma spectrometry is also con- veniently carried out using the instrument. Main chassis solid state circuitry, excluding the scintillation probe and preamplifier, comprises a wide-range high voltage supply, double delay line pulse amplifier, split-window gain stabilizer, single channel pulse height analyzer, six decade sealer, automatic timer, count rate meter, low voltage regulators, and a battery charger. Instrument power is supplied by a 3.5 Ib, 24 V, 2 A-hr NiCd rechargeable battery, also located in the 17 x 13 x 3 inch raain chassis, providing a maximum of 20 hours continuous operation. All elec- tronic circuits, except the battery charger, are fabricated in plug-in modules each 6 x 1.5 x 3 indies in size. The main chassis mounts in a glass fiber transit case, measuring 14 x 19 x 6 inches, which provides approximately one inch of foam padding to the chassis and components. Opening the hinged transit case lid exposes the main panel and module controls for convenient use by the operator. An identical transit case with shaped padding is provided for the probe with preamplifier, collimators, and probe stand. Special considerations which permit high performance with low power circuitry are described.