A New Semiconductor Material, LiInGaSe2, for Neutron Detection

Statement of the Problem or Situation that is Being Addressed There is a critical need for better a neutron detection technology that can be applied to materials control and accounting, including process monitoring, which can provide specialized functionality simultaneous with decreased intrusiveness on operations. This need is well aligned with the goal of developing and demonstrating the next generation of nuclear materials management for the peaceful use of civilian nuclear energy, set by Materials Protection, Accounting, and Control Technologies (MPACT) campaign. The mission of the MPACT program is to enable next-generation nuclear material management for advanced fuel cycles. Statement of how the Problem or Situation is Being Addressed To confirm the presence of a particular isotopes like fissile isotopes or induced fission materials, neutron detection techniques are among the most reliable methods. Spectroscopic gamma-ray detection techniques are useful but have one significant limitation; that is in the presence of a dense surrounding material such as lead, gamma ray attenuation can be significant, ultimately masking gamma signatures. Under these circumstances, and since neutrons easily penetrate dense and high atomic number materials, the detection of neutrons provides a more accurate measurement of fissile isotopes or induced fission materials. Therefore, an efficient and accurate neutron detector is an important component in the overall scheme of detecting and identifying special nuclear materials, and an integral component of radiation detection and identification instruments. RMD is proposing the use of a new semiconductor material, LiInGaSe2, that can provide these capabilities in a compact and robust form-factor with exceptional detection performance. What is to be done in Phase I? Key processes will be the crystal growth of semiconducting LiInGaSe2 material, and fabrication of neutron detectors. In Phase I, the LiInGaSe2 will be studied to improve crystal quality, optimize the growth technique, along with parallel efforts in material purification to boost electronic performance. Multiple iterations of materials will be produced, with subsequent characterization of physical, chemical, and electronic properties. A wide range of radiation testing will occur, primarily focused on sensitivity and selectivity for the neutron detector. At Phase I completion, RMD will be well positioned to move into detector construction and instrumentation design in Phase II. Commercial Applications and Other Benefits The most relevant benefit of furthering the development of LiInGaSe2 material is improving and advancing the scope of tracking and controlling nuclear materials in and outside nuclear and pyroprocessing facilities. Potential customers include scientists and engineers who on the behalf of the DOE and IAEA monitor and verify nuclear installations. Another security opportunity is radiation detection systems that can be employed by first responders and inspectors located at the Nation’s borders and ports. Non-security applications include non-destructive testing and scientific research.