Rapid detailed characterization of concrete shielding blocks utilizing internal natural radinuclides for calibration |
| |
Authors: | R J McDonald A R Smith D L Hurley E B Norman M R Schoonover |
| |
Institution: | (1) Nuclear Science Division, Ernest Orlando Lawrence Berkeley National Laboratory, #1 Cyclotron Rd, 94720 Berkeley, CA, USA;(2) Environmental Health and Safety Division, Ernest Orlando Lawrence Berkeley National Laboratory, #1 Cyclotron Rd, 94720 Berkeley, CA, USA |
| |
Abstract: | Following many years of productive research, the 184-inch Cyclotron, the SuperHILAC, and the BEVALAC accelerators at the Berkeley
Laboratory were closed, leaving thousands of concrete shielding blocks available for reuse, recycling, or disposal. The process
history of these blocks precludes free release pending radiological characterization. This paper describes a procedure whereby
a high efficiency shielded germanium spectrometer is used to rapidly characterize natural and man-made activity within the
blocks. The spectrometer is moved up to the block and 5 minutes of data are collected at the point on the block that registers
highest on a micro-R meter. Sensitivity is better than 1 pCi/g (0.037 Bq/g) for Co-60 and Eu-152, the prominent man-made activities
observed. One-time calibration of the detector system is obtained from a sample of concrete, drilled with a hammer drill,
counted in our low-background facility, and compared to crushed rock with known U, Th, and K activity. A simple relationship
exists between the counts/minute observed in a characteristic gamma-ray peak and the activity in the block. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|