Evaluation of Health Physics Instruments Model 2080 Pulse Neutron Survey Meter, Model 6030 Ion Chamber, and Model 1030 Pulse Survey Meter in a Linear Accelerator Produced Neutron Field

E. Anderson¹; K. Claver¹; B. Schrader²; and R.R. Brey¹ (¹Idaho State University - Dept. of Physics/Health Physics Program; ²Idaho National Laboratory)

The measurement of neutron fields is of increasing importance considering devices that generate pulsed neutron radiation as employed in homeland security. An example; pulsed linear accelerators that generate large Bremsstrahlung fields, and the subsequent photonuclear-reaction-generated pulsed neutron fields. Questions exist as to the efficacy of available detectors and neutron dose-equivalent type survey meters to quantify these fields complicated by changing energy spectra. Are these neutron detection devices truly independent of charge collection time and the magnitude of charge magnitude? A project to evaluate this question is underway. Phase I includes consideration of detector response in a well characterized source field. Phase II considers a linear accelerator produced neutron-field generated using the (γ,238U) reaction to produce neutrons. During this phase the accelerator radiation pulse width and pulse height remain constant while pulse repetition rate is varied. Phase III involves keeping the repetition rate constant and varying the width of the accelerator radiation peak while maintaining the area under the peak. An additional investigation involves maintaining the repetition rate and pulse width constant while varying the pulse amplitude. The independent variable of survey meter dose-equivalent response versus that of known field conditions from these experimental investigations is presented.

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