Design Criteria for High Resolution Gamma-Ray Body Counting Systems

Droughi, Nouri Ali (1992) Design Criteria for High Resolution Gamma-Ray Body Counting Systems. MSc(R) thesis, University of Glasgow.

Abstract

For several decades whole- and partial-body counters have used NaI(Tl) detectors for gamma-ray analysis which have provided good sensitivity but have possessed poor gamma-ray resolution. With the increasing availability of more efficient germanium semi-conductor detectors, which offer high resolution gamma-ray spectrometry as well as workable sensitivity, body counting techniques are slowly changing over to their use either as an adjacent to or a replacement for NaI(Tl) or phoswich detectors. This thesis contains a description of preliminary studies to investigate the requirements of germanium detector body counting systems with regard to shielding,background,detector volume and other relevant factors with the ultimate goal of setting up such a system at the Scottish Universities Research and Reactor Centre. Following recommendations made in recent years for the need to monitor members of the population, particularly those living near nuclear installations, the ability to measure the low energy photon emissions from such radionuclides as uranium, plutonium and americium, in addition to the high energy emissions from radiocaesium and other fission products now has a renewed emphasis in the field of body measurements. The thesis outlines some aims and progress towards the design and construction of "shadow-shield" body counting arrangements based on existing Nal(Tl) counter of this type but using a 30% efficient germanium detector and a thin planar germanium detector for trial measurements. From a literature review combined with the observed data, a design for a whole-body counter is suggested which should enable the traces of natural decay series radioactivities in the body to be quantified in addition to the easily-measured body potassium. The best approach for an indicator for the presence of plutonium, appears to be the measureme it of the skull, tibia or knee where the overlying tissue is thin, reducing low energy photon attenuation. For population studies of radionuclides it may be possible to sum individual spectra to obtain adequate sensitivity and precision at the very low levels of activity expected.

• Item Type: Thesis (MSc(R))
• Qualification Level: Masters
• Additional Information: Adviser: Brian William East
• Keywords: Nuclear physics and radiation
• Date of Award: 1992
• Depositing User: Enlighten Team
• Unique ID: glathesis:1992-74609
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 13 Nov 2019 15:58
• Last Modified: 13 Nov 2019 15:58
• URI: https://theses.gla.ac.uk/id/eprint/74609