Investigation of the Response Characteristics of a Portable Portal Monitor

M. Balzer; R.R. Brey; A. Hunt; and T.F. Gesell (Idaho State University - Dept. of Physics/Health Physics Program)

We have investigated the performance characteristics of a TSA Systems Ltd. model TPM 903 portal monitor. This device is intended to be used as a portable system to meet emergency response needs. An extensive evaluation of the monitor’s response in the 3-dimensional volume near and between the detectors has been conducted using point sources producing various types and energies of radiation. The sources used were a 3,707 kBq 137Cs button source, a 3,900 kBq 60Co button source and a 1x107 neutron s-1 252Cf source. Also, a Monte Carlo model of the TPM 903 portal monitor was constructed and run (one million particles per run). The model output compared favorably with field measurements. The methods used in this paper may serve as a prototype for considering the response of such devices and may also serve as a basis for comparing the characteristics of response among various designs. A complete description of the portal monitor's response characteristics in the 3-dimensional volume surrounding the detectors is provided.

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