MONTE CARLO MODELING OF A DETECTOR SYSTEM FOR GAS PHASE URANIUM ENRICHMENT MEASUREMENTS

Year
2010
Author(s)
D.W MacArthur - Los Alamos National Laboratory
D.W MacArthur - Los Alamos National Laboratory
Martyn T. Swinhoe - Los Alamos National Laboratory
Martyn T. Swinhoe - Los Alamos National Laboratory
K. D. Ianakiev - Los Alamos National Laboratory
K. D. Ianakiev - Los Alamos National Laboratory
J. M. Goda - Los Alamos National Laboratory
J. M. Goda - Los Alamos National Laboratory
Marcie Lombardi - Los Alamos National Security and California Poison Control System
Marcie Lombardi - Los Alamos National Security and California Poison Control System
C.E. Moss - Los Alamos National Laboratory
C.E. Moss - Los Alamos National Laboratory
A. Favalli - Los Alamos National Laboratory
A. Favalli - Los Alamos National Laboratory
Abstract
The classical approach to measure the uranium enrichment in the gas phase is spectroscopy measurements of the 186-keV gamma emission from 235U. However for the interpretation of the measurements a complication arises from the contribution to the 186-keV peak due to the uranium deposits on the wall of the pipe. In this paper we present the results of the numerical evaluation of a detector system for enrichment measurement with regard to the identification of the two contributions to the 186-keV gamma emission. This was done with a detector system in which the 186-keV emission rate was measured in different geometry configurations with different distances between the detector and the pipe. For the detector system, we have chosen to use scintillation detectors (NaI) that require low maintenance and are less expensive than HPGe detectors. We focus on the geometrical design of the system by means of Monte Carlo numerical calculations. We present preliminary results of the effect of changing the distance between the front face of the detector and the gas pipe on the efficiency of the detector when UF6 gas or uranium deposits are measured.