Seminar: Microstructured Semiconductor Neutron Detectors

Dr. Douglas McGregor, Kansas State University

All dates for this event occur in the past.

E141 Scott Lab
E141 Scott Lab
201 W. 19th Ave.
Columbus, OH 43210
United States

Semiconductor diode detectors coated with neutron reactive materials have been investigated as neutron detectors for many decades, and are fashioned mostly as planar diodes coated with 10B, 6LiF, or Gd.  Although effective, planar detectors coated with boron and LiF are limited to less than 5% intrinsic thermal neutron detection efficiency. Detectors coated with Gd can achieve higher efficiencies, but the low-energy reaction products are difficult to distinguish from background radiations. Over the past decade, microstructured semiconductor neutron detectors (MSND) have been investigated, and can now achieve a tenfold increase in neutron detection efficiency over the simple planar diode designs. These new semiconductor neutron detectors are fashioned with a matrix of microstructured patterns etched deeply into the semiconductor substrate and, subsequently, backfilled with neutron reactive materials. Intrinsic thermal-neutron detection efficiencies exceeding 30% have been achieved with devices no thicker than 1 mm while operating on less than 5 volts. Double-sided devices perform with over 50% thermal neutron detection efficiency, and theoretical models of newer designs indicate that intrinsic thermal neutron detection efficiencies greater than 70% can be achieved. The detectors have been integrated with compact low-noise and low-power electronics, thereby, allowing for rugged instruments and compact arrays to be fashioned from the devices. A discussion on the physics, performance and instrumentation of these MSNDs will be presented.

About the Speaker

Prof. Douglas McGregor received B.A. (1985) and M.S. (1989) degrees, both in Electrical Engineering, from Texas A&M University. He then received M.S. (1992) and Ph.D. (1993) degrees, both in Nuclear Engineering, from the University of Michigan. His Ph.D. research reported the use of GaAs as a room-temperature-operated gamma-ray detector. He served as a research scientist at Sandia National Laboratories and the University of Michigan between the years of 1994 to 2001. He joined the faculty at Kansas State University (KSU) in 2002, where he now holds the rank of University Distinguished Professor and is the Boyd D. Brainard Departmental Faculty Chair in Mechanical and Nuclear Engineering. He is also the director of the KSU Semiconductor Materials and Radiological Technologies (SMART) Laboratory, a >9000 sq ft facility dedicated to the discovery of innovative radiation detector materials and designs. He has over 30 years of experience in the fields of semiconductor device theory and fabrication, radiation detection and measurement, semiconductor radiation detector design, fabrication and characterization, and teaches radiation detection and detector design at the undergraduate and graduate levels. Since 1993, Prof. McGregor has introduced numerous alternative designs for semiconductor-based gamma-ray and neutron detectors and holds records for room-temperature gamma-ray spectrometers and solid state thermal neutron detectors. He has received four R&D 100 awards for radiation detector designs. Prof. McGregor has authored or co-authored over 200 research publications on radiation detectors, five radiation detection book chapters, and has 16 allowed US patents with 5 more US patents pending on radiation detector designs.

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