Compact and Efficient Cold and Thermal Neutron Collimators

A joint collaboration between NOVA Scientific, Inc (NOVA) of Sturbridge MA and the Space Sciences Laboratory (SSL) at the University of California-Berkeley proposes to develop a novel type of compact thermal neutron collimator based on 10B and Gd-doped glass performs. The new type of neutron collimator will be optimized for imaging of cold and thermal neutron detectors based upon imaging detectors integrating the novel neutron sensing microchannel plates (MCPs) and the powerful Medipix-2 readout. These compact collimators can be employed 1) importantly, in collimation of more divergent neutron beams which will permit high resolution imaging, and 2) to effectively reduce post-scattered neutrons arriving at the detector, providing improved contrast and higher spatial resolution for researchers. It is expected that the final collimators will have thicknesses of only 5-10 mm with large formats and multi-axis alignment. Final collimator optimization will be aided by computer modeling. The performance improvements will be detailed using neutron sources at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory. New neutron radiographic imaging facilities at SNS will require detectors with better position resolution and rate capability. The Phase I program assessed cold and thermal neutron performance of selected collimators which closely followed the theoretical the computer modeling. Using a high resolution neutron-sensitive detector, the collimators exhibited significant improvements in beam quality and scatter rejection for both cold and thermal neutrons. The Phase II would further optimize the collimators and the alignment permitting improved beam characteristics for high resolution radiography through full field of view and improved contrast through reduction in neutron scattering between the target and detector. The improvement in detection sensitivity expected from these new thermal neutron components has already evidenced increased interest within the larger scientific community, supporting diverse areas as biological imaging (e.g. in-situ root growing); inspection of nuclear fuel, explosives detection, analysis of museum objects (unique samples!), precise neutron beam formation and monitoring, etc. The successful development of this critical thermal neutron component will also continue the US leadership position in neutron science. Commercial Applications and other Benefits as described by the awardee: The development of improved and compact neutron collimator hardware will provide neutron radiographic imaging systems with significantly higher spatial resolution for neutron studies of biological and material science specimens. Researchers will benefit in achieving improved contrast by reducing post target scattering and improved collimation of neutron beams. The component development will also continue to support US leadership in neutron science.