My Master’s Thesis was published in August of 2014 after defending the thesis to a committee of Purdue Nuclear Engineering and Purdue Health Physics faculty members in May of 2014. The thesis includes business confidential material and will not be published until 2016. I will post the full text at that time.
Multiphysics Modeling in Optimization of Acoustically Tensioned Metastable Fluid Neutron Detectors
Aug 15, 2014
Citation
Hagen, A. (2014). Multiphysics Modeling in Optimization of Acoustically Tensioned Metastable Fluid Neutron Detectors. Purdue University.
Abstract
Neutron detection is currently very important in nuclear energy, and related homeland security and health physics fields. State of the art detectors currently fall short in many areas, especially in cost and ruggedness.
Tensioned Metastable Fluid Detectors are being developed at Purdue University that boast high intrinsic efficiency, rapid on-off times, detection of fast and thermal neutrons, possible directionality, ease of use, and above all, drastically reduced cost.
Tensioned Metastable Fluid Detectors operate on the principle that when a fluid is placed into a metastable state by inducing negative (tensile) pressures on it, it may cavitate when subjected to a neutron collision event.
One way to include negative pressures is using acoustic energy, as is done in the Acoustically Tensioned Metastable Fluid Detector. The design of these detectors requires intricate knowledge of the states of metastability (enabling substance detection) that will develop in the chamber.
A general purpose simulation model and platform in 3D have been developed that combine the electromechanical and piezoelectric aspects of the driving piezoelectric device, the structural mechanical response of the resonant acoustic chamber, and the acoustic response of the detection fluid. This thesis describes studies which demonstrate attainments for drastically increasing the simulation accuracy, from \( >3\% \) error to less than experimental error. A sensitivity analysis of four important parameters is presented to discuss the effect of physical perturbations on the model. This thesis also describes several methodologies developed and deployed for verifying the simulation framework, including novel non-invasive methods.
Utilizing this simulation framework, this thesis then describes efforts to make the simulation an easily usable design tool to experimenters. It goes on to describe several practical design resonant parameter interplays which alleviate issues and allow for greater flexibility of the system parameters.