Coaxial germanium detectors in the Y-12 in vivo monitor

Technical Report · Mon Aug 13 04:00:00 EDT 1984

OSTI ID:6608471

Sheppard, G A

Germanium detectors have been evaluated as an alternative to thallium-activated sodium iodide (NaI(Tl)) detectors for in vivo uranium lung-burden analysis. In an assessment of the relative merits of planar and coaxial hyperpure germanium (HPGe) detectors, it was observed that, for the /sup 235/U 186-keV gamma rays, the tested coaxial detector was 235% more sensitive than the planar. Accordingly, a trio of closed-end coaxial n-type HPGe detectors was assembled, complete with a system of liquid nitrogen (LN/sub 2/) level monitors and logic-controlled valves to automatically maintain an LN/sub 2/ supply to the detectors. Using anthropomorphic phantom torsos for study with the germanium system, detection limits have been established, sensitivity curves have been derived, effects of chest-wall thickness and composition have been measured, and optimal detector placement has been determined. In comparison studies with the existing NaI(Tl) detection system, the germanium system performed with higher resolution, better low-energy efficiency (facilitating the distinction between internal and external contamination), reduced sensitivity to background radiation, and higher stability with respect to temperature fluctuations and the passage of time. 9 references, 6 figures.

• Research Organization: Oak Ridge Y-12 Plant, TN (USA)
• DOE Contract Number: AC05-84OS21400
• OSTI ID: 6608471
• Report Number(s): Y-2340; ON: DE84016211
• Country of Publication: United States
• Language: English

Related Subjects

440102* -- Radiation Instrumentation-- Radiation Dosemeters
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
61 RADIATION PROTECTION AND DOSIMETRY
655003 -- Medical Physics-- Dosimetry
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
BODY
BODY BURDEN
COMPARATIVE EVALUATIONS
DATA
DOSIMETRY
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
GAMMA DOSIMETRY
GE SEMICONDUCTOR DETECTORS
HEAVY NUCLEI
INFORMATION
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LUNGS
MEASURING INSTRUMENTS
MINUTES LIVING RADIOISOTOPES
MOCKUP
NAI DETECTORS
NUCLEI
NUMERICAL DATA
ORGANS
PERFORMANCE TESTING
PHANTOMS
RADIATION DETECTORS
RADIOISOTOPES
RADIOSENSITIVITY
RESPIRATORY SYSTEM
SCINTILLATION COUNTERS
SEMICONDUCTOR DETECTORS
SOLID SCINTILLATION DETECTORS
STRUCTURAL MODELS
TESTING
URANIUM 235
URANIUM ISOTOPES
X-RAY DOSIMETRY
YEARS LIVING RADIOISOTOPES