A neutron portal monitor for vehicles
We have designed and built a portal vehicle monitoring systems 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. Our 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 of another DOE facility in 1987. 7 refs.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6240221
- Report Number(s):
- LA-UR-87-2117; CONF-870713-10; ON: DE87011751
- Resource Relation:
- Conference: 28. INMM annual meeting on safeguards: a mature technology, Newport Beach, CA, USA, 12 Jul 1987; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
Similar Records
Organic liquid scintillation detectors for on-the-fly neutron/gamma alarming and radionuclide identification in a pedestrian radiation portal monitor
Integrated neutron/gamma-ray portal monitors for nuclear safeguards
Related Subjects
NEUTRON MONITORS
DESIGN
NUCLEAR FACILITIES
ENTRY CONTROL SYSTEMS
RADIOACTIVE MATERIALS
DETECTION
VEHICLES
MONITORING
GAMMA RADIATION
HELIUM 3
PLUTONIUM
ACTINIDES
CONTROL SYSTEMS
ELECTROMAGNETIC RADIATION
ELEMENTS
EVEN-ODD NUCLEI
HELIUM ISOTOPES
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
MATERIALS
MEASURING INSTRUMENTS
METALS
MONITORS
NUCLEI
RADIATION MONITORS
RADIATIONS
STABLE ISOTOPES
TRANSURANIUM ELEMENTS
055001* - Nuclear Fuels- Safeguards
Inspection
& Accountability- Technical Aspects