Development and applications of a gamma-blind economically simplified acoustically tensioned metastable fluid particle detector

Kevin F Fischer, Purdue University

Abstract

High prices of conventional nuclear particle detection systems along with the diminishing supply of Helium-3 are motivating the need for new, novel nuclear particle detectors that are more economical (i.e. low cost and made with readily obtainable materials). Acoustically Tensioned Metastable Fluid Detectors (ATMFDs) show the potential for replacing conventional systems while remaining gamma blind, having the ability to detect a broad range of neutron energies, and possess the potential to provide directional information from a single system all while cutting the costs by orders of magnitude. Multiple styles of ATMFD systems have been developed (including the cylindrically shaped Directional-ATMFD and conically shaped ATMFD) at Purdue University in order to meet the needs of the current demand. This thesis presents the cost and performance optimized Economically Simplified-ATMFD (ES-ATMFD) system concept and design. Processes for optimizing detector parameters and qualifying these chambers have been established both theoretically and experimentally under guidance from a multi-physics, multi-dimensional nite element simulation using the COMSOL® architecture. Wall-mounted microphone sweeps, power sweeps, and acoustic profile benchmarking experiments also yield valuable information as to the optimal parameters for chamber geometry and operational parameters, resulting in the ES-ATMFD system. Three different ES-ATMFD drive systems have been created, qualified, benchmarked, and tested to successfully operate these dynamic systems. Detector response curves were taken with both plutonium-beryllium (2 x106 n/s random spectrum) and californium-252 (1.18x105 n/s fission spectrum) neutron sources to assess and qualify the ES-ATMFD for detection capabilities. In order to qualify the ES-ATMFD system versus conventional neutron detectors, head-to-head experiments were performed with a SNOOPY™ style moderated BF3 neutron detector, from which results yielded a neutron dose calibration curve for the Economically Simplified-ATMFD system. Beyond dose monitoring, evidence is provided to show that the ES-ATMFD systems could provide a low-cost, drop-in solution for portal monitoring applications. Although estimates for the 252Cf neutron monitoring standard requirements are below the stated 2.5 cps/ng, there is plenty of potential for improvement that has been demonstrated by driving the system at higher powers and in different operational modes. Future work is suggested that can also increase chamber sensitivity to a wider range of neutron energies and make the systems operationally stable for desired periods of time.

Degree

M.S.

Advisors

Taleyarkhan, Purdue University.

Subject Area

Nuclear engineering

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