Modern Neutron Detectors with Fast Timing Resolution

Thermal neutrons are a vital imaging modality with wide ranging applications, exemplified by worldwide endeavours to construct and operate the next generation of accelerator-driven neutron sources with significantly increased neutron flux and, hence, brightness and image contrast. In addition, a high spatial resolution and information about the neutron energy is often desired. The latter is commonly provided by a time-of-flight measurement. These user-driven demands to obtain the best possible image pose significant challenges to the design of the neutron sensor system. The neutron sensor needs to be highly efficient in detecting thermal neutrons, provide the desired spatial and temporal resolution, and has to operate at high count rates. Segmented photon sensors like Multi-Anode Photo Multiplier Tubes (MAPMT) or systems based on Micro Channel Plates (MCP) have been proven in other fields to meet the demands on efficiency, rates, spatial and temporal resolution. Combining these photon sensors with suitable neutron converters, e.g. Lithium-loaded glass scintillators, will provide a neutron detection system capable of meeting the requirements of the next generation of spallation neutron sources. One system based on GS-20 scintillator coupled to a Hamamatsu H12700 MAPMT will be described in detail, as will be the concept of a system based on gadolinium-coated silicon structures coupled to a segmented electron detector. (author)