A neutron portal monitor for vehicles
The authors have designed and built a portal vehicle monitoring system for detecting neutron-emitting special nuclear material (SNM) such as plutonium. Monte Carlo calculations were used to optimize the design of the 15-cm-deep x 122-cm-high x 244-cm-long detector chambers, which utilize /sup 3/He proportional counters inside a hollow polyethylene box. Results for a variety of parametric studies, including polyethylene thickness and detector number, are described. The experimental measurements are in good agreement with the computer calculations. The monitor's decision logic uses the Sequential Probability Ratio Test (SPRT) on Poisson distributed counting data, which is superior to other statistical tests in many applications. We performed computer simulations of the SPRT logic to determine expected false-positive decision rates. A controller unit of our design that uses this SPRT was built commercially. The cost of the complete monitoring system is similar to that of vehicle portal monitors that detect gamma rays. This new neutron monitor can serve as an addition to standard gamma-ray vehicle portals or as a stand-alone portal monitor in particular safeguards monitoring situations. The monitor is being tested at Los Alamos and is scheduled for in-plant evaluation at another DOE facility in 1987.
- Research Organization:
- Los Alamos National Lab., Los Alamos, NM 87545
- OSTI ID:
- 5816086
- Report Number(s):
- CONF-870713-; TRN: 88-002570
- Journal Information:
- Nucl. Mater. Manage. Annu. Meet. Proc.; (United States), Vol. 16; Conference: 28. INMM annual meeting on safeguards: a mature technology, Newport Beach, CA, USA, 12 Jul 1987
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NEUTRON DETECTORS
COMPUTER-AIDED DESIGN
VEHICLES
SECURITY
COUNTING TECHNIQUES
DOMESTIC SAFEGUARDS
GAMMA DETECTION
MONITORS
MONTE CARLO METHOD
NUCLEAR MATERIALS MANAGEMENT
PHYSICAL PROTECTION
PLUTONIUM
POISSON EQUATION
POLYETHYLENES
RADIATION MONITORING
US DOE
ACTINIDES
DETECTION
DIFFERENTIAL EQUATIONS
ELEMENTS
EQUATIONS
MANAGEMENT
MEASURING INSTRUMENTS
METALS
MONITORING
NATIONAL ORGANIZATIONS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PARTIAL DIFFERENTIAL EQUATIONS
POLYMERS
POLYOLEFINS
RADIATION DETECTION
RADIATION DETECTORS
SAFEGUARDS
TRANSURANIUM ELEMENTS
US ORGANIZATIONS
055001* - Nuclear Fuels- Safeguards
Inspection
& Accountability- Technical Aspects