Title :
An Absolutely Calibrated Source of 6.13 MeV Gamma-Rays
Author :
Mach, H. ; Rogers, D.W.O.
Author_Institution :
Division of Physics National Research Council of Canada, Ottawa, Canada K1A OR6
fDate :
4/1/1983 12:00:00 AM
Abstract :
At the 340 keV resonance in the 19F(p, ¿¿)16O reaction, after kinematic corrections, there is a 1:1 correspondence between the 55/s=deg/ yield of alpha particles feeding the 6.13 MeV state and the yield of 6.13 MeV photons observed at 55° to the proton beam. The 55° intensities of alpha particles feeding the various states in 16O were found to be: ¿6.05: ¿6.13: ¿6.92: ¿7.12 = ¿0.14: 100: 0.08: 2.6 which implies the only non-negligible contaminant is a 7.12 MeV gamma-ray radiation with an intensity of 2.6%. After a number of small corrections, including those for photon attenuation in the target backing and air, the fluence of 6.13 MeV gamma-rays can be determined absolutely with an uncertainty of ~1%. Excellent agreement was obtained in a comparison of the calculated and measured efficiencies of a 5 à 4" NaI detector. The calibration of Ge(Li) detectors required an aluminium coated target to avoid a Doppler tail on the 6.13 MeV photon peaks caused by 16O nuclei recoiling from the surface of the CaF2 target.
Keywords :
Alpha particles; Aluminum; Attenuation; Calibration; Detectors; Kinematics; Particle beams; Pollution measurement; Resonance; Tail;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.1983.4332573