Portable instrumentation for quantitatively measuring radioactive surface contaminations, including 90 Sr

This paper describes the development and application of portable instrumentation capable of quantitatively measuring most transuranics, activation products, and fission products, including Strontium 90, on almost any contaminated surface in nearly any location. Two germanium diode spectrometers, specifically adapted to portable, multipurpose use, provide measurement capability for both gamma rays and X rays. One is a large volume intrinsic germanium coaxial detector having a FWHM resolution of 1.82 KeV at the 1332 KeV line of Cobalt 60 and a relative efficiency of 32.8%. The other is a 2000 mm2 planar intrinsic germanium detector housed in an end cap with a thin beryllium window and having a resolution of 739 eV at the 122 KeV line of Cobalt 57. Both crystals are mounted in 12-inch long end caps and attached to portable liquid nitrogen cryostats with nominal holding times of 16 hours. Data acquisition is normally accomplished with a 4096 channel analyzer and transferred to cassette tape for subsequent computer reduction and analysis. Data reduction is normally done with the aid of a PDP 11-44 computer either following ''reading'' of the data stored on tape or by direct connection to the laboratory-based computer. Transuranic elements can be identified and quantified on the basis of their characteristic K or L shell X-ray emission lines. The only difficulty in these procedures is obtaining suitable calibration data