Advanced Energy-Resolving Imaging Detectors for Applications at Pulsed Neutron Sources

NOVA Scientific proposes the development of efficient position sensitive detectors capable of time-tagging epithermal energy neutrons with high accuracy and efficiency. These devices will be able to perform energy-resolved imaging at the pulsed neutron sources and detect every neutron with spatial resolution of & lt; 60 m and timing resolution & lt; 1 s for thermal neutrons and & lt;100 ns for epithermal neutrons. The pulsed structure of neutron beam enables measurement of neutron energy through the time of flight technique. The unique capability to measure energy of each detected neutron provides the ability to conduct experiments with all the energies at the same time, including epithermal, thermal and cold neutron ranges. Simultaneous detection of multiple Bragg edges, for example, enable studies in crystallographic structure, strain, phase, texture, and composition distribution. The proposed detection technology will be complimentary to the large array detectors implemented currently at the neutron scattering facilities. The epithermal detector is based on the novel neutron sensitive Microchannel Plates developed by NOVA Scientific combined with the fast and high resolution readout electronics developed by the University of California. With advanced electronics and software, the Timepix readout can detect time of arrival of up to 25,000 particles in 1 ms within a 28 x 28 mm2 active area, very short readout time of 280 s, along with low readout noise. Phase I assessed and down selected the options to modify the MicroChannel Plate to achieve a high cross-section to epithermal neutrons. The program demonstrated resonance absorption imaging of differing materials, imaging of fuel pellets, 2-D imaging of steel welds, and strain mapping at differing loads, remote temperature measurements, and others. Phase II will fully establish the epithermal-sensitive Microchannel Plates and further modify the electronics, firmware and data acquisition software. The integrated detector will be evaluated at the Spallation Neutron Source at Oak Ridge and the Los Alamos Neutron Science Center. The detector will be utilized in further addressing pulsed beam line applications with major emphasis on the epithermal energy range.