Our group plans to develop a novel type of thermal and cold neutron counting detector based on Boron and Gadolinium doped microchannel plates (MCPs). The new type of neutron imaging detectors will be optimized for imaging thermal neutrons with high detection efficiency (up to 50 %) and even higher for cold neutrons, spatial (~55 µm) and time resolution of ~1 ms (or gated detection with gate accuracy <1 µs) for each detected neutron. The counting rate of detector with Medipix readout can be as high as >100 MHz with active area scalable to rectangular configuration of 28 x (N*14) mm2. Another attractive feature of the detector will be its ability to be synchronized with the external trigger, allowing energy selective imaging with a pulsed source. The neutron imaging devices will be rigorously tested at a neutron beamline, in collaboration with our colleagues from Nova Scientific. The proposed detection system will greatly facilitate thermal neutron imaging with very high counting rates, sensitivity and resolution, substantially increasing the accuracy of existing experiments (e.g. SNS residual stress profile measurements with the engineering instrument Vulcan, studies of small samples under very high pressures with the high pressure instrument SNAP, fuel cell studies), and may additionally open up entirely new areas of non destructive testing with modern neutron sources.
Neutrons are nuclear particles with no electronic charge which are very useful for studying the details of structure at the atomic level. They are particularly useful because they can probe atomic arrangements and study important materials properties such as magnetism and the vibrational properties of atoms in a crystal. However, detecting neutrons has always been a challenge. This proposal plans to use pieces of glass with many fine holes as a neutron detector. The neutrons pass through the holes, interact with the glass at the edge of the holes, and then, because of the special properties of the glass (addition of Boron or Gadolinium) the neutrons are converted to light, which can then be detected. The small size of the holes allows very high precision in locating the position of each neutron, so that images can be constructed. In addition, this detector system can count neutrons at the same rate that they are produced in the best neutron sources, allowing experiments that take full advantage of those new sources.
