The Health Physics Program at the National Bureau of Standards Linac

A three-person Accelerator Health Physics team provides continuous radiation safety service for the National Bureau of Standards 150-MeV linear electron accelerator (Linac), which operates on a five days per week, 24 hours per day schedule, with one day per month down-time scheduled for maintenance. This team also serves the synchrotron ultraviolet light radiation facility (SURF), two Van de Graaffs, some other electrostatic accelerators, and several high-energy x-ray generators. Although the Linac is not licensed by a safety-regulating agency, as is the NBS Research Reactor, Health Physics makes no distinction between the two sources in providing coverage. Various regulations do impact on operations, e.g., the NRC dose totals and effluent releases and the OSHA requirements. Film, thermoluminescent dosimeters (TLD), and direct-reading pocket dosimeters are used for personnel dosimetry. The usual array of portable and fixed radiation survey meters and activation devices and some of the high-energy multi-particle activation techniques are used for area monitoring. Environmental surveillance is performed with TLD´s, tissue-equivalent ion chamber, and a grass and soil assay program. Integrated Health Physics programs for all the NBS radiation facilities do instrument calibrations, training for Health Physics and operating staffs, administrative control of radioactive materials, waste management, and data compilations. The Linac began operations in 1965 and some workers have been affiliated with the facility since that time, but as at any facility, there have been personnel changes.