ABSOLUTE THERMAL NEUTRON DETERMINATION. PART II. ABSOLUTE BETA COUNTING OF INDIUM FOILS
Correction factors for the effect of thickness on the selfscattering, self-absorption, and backscattering of beta particles from indium foils were determined for irradiated foils of 0.03 to 100 mg/cm/sup 2/. The data were corrected for the activity produced by epithermal neutrons, self-shielding of thermal neutrons by the foil during irradiation, the backscatter from the foil support, and the contributions of gamma and x rays to the counting rate. The multiple beta spectra of indium produced a minimum in the self-absorption and self-scattering correction curve in the GM detector at approximately 1 mg/cm/ sup 2/ and a maximum at approximately 12 mg/cm/sup 2/. The selfabsorption curve for indium in the 2 pi counter has the expected shape for a beta emitter with multiple spectra. The self-scattering and self-absorption correction factors for a 100 mg/cm/sup 2/ indium foil are approximately 1.5 for a GM detector at 7% geometry and approximately 3 for a 2 pi counter. (D.L.C.)
- Research Organization:
- North American Aviation, Inc., Downey, Calif.
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-15-024964
- OSTI ID:
- 4021712
- Report Number(s):
- NAA-SR-1137(Pt.II)
- Country of Publication:
- United States
- Language:
- English
Similar Records
ABSOLUTE CALIBRATIONS OF THERMAL NEUTRON FLUX DENSITIES
A RECALIBRATION OF THE NBS STANDARD THERMAL NEUTRON FLUX