Accession Number : AD0638725

Title :   A MONTE CARLO CALCULATION TO SIMULATE DETECTOR RESPONSE TO UNDERWATER GAMMA RAYS.

Corporate Author : NAVAL ORDNANCE LAB WHITE OAK MD

Personal Author(s) : Madigosky,Susan W. ; Simons,Donald G.

Report Date : 14 JUL 1966

Pagination or Media Count : 70

Abstract : The response function of a scintillation detector surrounded by a monoenergetic gamma-ray source which is uniformly dispersed in an infinite volume of water has been calculated. The method of calculation is that of random sampling (Monte Carlo) and is programmed for the IBM 7090 computer. Rather than starting the sampling by taking gamma-ray sources at random throughout the volume of water the response is determined for a weighted set of secondary gamma-ray sources taken to be on the surface of the detector system. The spectrum of secondary energies chosen is taken to be the quilibrium flux distribution which is obtained in an infinite volume of water in which there is no detector. The detector response is determined by a superposition of the weighted secondary sources. Detector response has been obtaine for gamma-ray sources from Cr51, Cs137, K40, Na24, and Ce144. The calculated response for these sources agrees quite well with the measured response in shape but not in magnitude. Here, it is found that the artificial spectra have an amplitude which is approximately 1.6 times the measured spectra. This difference appears to be mainly due to two sources: the difference in geometry between the actual spectrometer and the 'spectrometer' used for the calculation and the approximation in which the distribution of secondary source neglects the presence of the detector. (Author)

Descriptors :   (*MONTE CARLO METHOD, *GAMMA COUNTERS), (*GAMMA RAYS, UNDERWATER), SIMULATION, COMPUTER PROGRAMMING

Subject Categories : Numerical Mathematics
      Nuclear Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE