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Solid-state neutron detector offers high sensitivity with reduced cost

National Renewable Energy Laboratory

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Technology Marketing Summary

Neutron detectors are vital in the national security effort to detect special nuclear material at the hundreds of U.S. ports of entry. Special nuclear material emits neutrons which rarely occur spontaneously, therefore detection can be correlated to the existence of special nuclear matter found in plutonium and plutonium based weapons. Currently, the most common type of neutron detector uses pressurized tubes containing rare Helium-3 gas. This 60 year old instrumentation is bulky, costly, and difficult to configure. Further, the shortage of Helium-3 following the Cold War resulted in a high price for Helium-3 and a reduced number of neutron detectors. Lowering costs and increasing functionality would increase the number of neutron detectors in use and hence increase national security. NREL scientists have a novel new approach to neutron detection that utilizes inexpensive processes which are widely used in the semiconductor industry.  In addition to neutron detection, this technology can be used in nuclear power neutron detection, and radiation monitoring in the medical industry.

Description

Using Boron-10 instead of Helium-3 gas, NREL scientists have created a simple, inexpensive large neutron detector consisting of detector sheets grouped in multi-stacked layers.  The multi-stack layers are then grouped into 2-dimensional arrays.

Each detector sheet consists of a thin, inexpensive substrate. The substrate is coated with four layers, a bottom electrode, neutron conversion layer, thin film silicon detecting layer, and top electrode.  The neutron conversion layer emits alpha particles when struck by a thermal neutron, which in turn are detected by the silicon detecting layer, indicating special nuclear material. The layers can be deposited on one or both sides of the substrate.

Stacking detector sheets into multilayer structures offer high sensitivity. Pixel connections extending to the side of the substrate allows for easy stacking of elements into a socket to the circuitry that processes the electronic pulse readout from each pixel. Additional thin substrates coated with a neutron conversion layer can be inserted between the detector sheets to increase the sensitivity through the neutron conversion products that travel through the air gap. Arranging multilayer stacks with their readouts onto a 2D board allows easy scale-up.

Benefits
  • Reduced cost
  • Eliminates use of Helium-3 gas
  • High sensitivity
  • Stackable
  • Scalable
Applications and Industries
  • Homeland security
  • Nuclear power neutron detection
  • Radiation monitoring in the medical industry
More InformationWO/2010/087844
HIGH SENSITIVITY, SOLID STATE NEUTRON DETECTOR
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Date
Patent 8,569,708
Patent
8,569,708
High sensitivity, solid state neutron detector
An apparatus (200) for detecting slow or thermal neutrons (160) including an alpha particle-detecting layer (240) that is a hydrogenated amorphous silicon p-i-n diode structure. The apparatus includes a bottom metal contact (220) and a top metal contact (250) with the diode structure (240) positioned between the two contacts (220, 250) to facilitate detection of alpha particles (170). The apparatus (200) includes a neutron conversion layer (230) formed of a material containing boron-10 isotopes. The top contact (250) is pixilated with each contact pixel extending to or proximate to an edge of the apparatus to facilitate electrical contacting. The contact pixels have elongated bodies to allow them to extend across the apparatus surface (242) with each pixel having a small surface area to match capacitance based upon a current spike detecting circuit or amplifier connected to each pixel. The neutron conversion layer (860) may be deposited on the contact pixels (830) such as with use of inkjet printing of nanoparticle ink.
National Renewable Energy Laboratory 10/29/2013
Issued
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL 07-30 International Application No. PCT/US09/32557PrototypeAvailable06/27/201106/27/2011

Contact NREL About This Technology

To: Ty Ferretti<Ty.Ferretti@nrel.gov>