Recent developments in multiplicity counting hardware at Los Alamos
Neutron coincidence counting has played an important role in determining the mass of fissile material in safeguards and nuclear industry samples. The principle is simple; the mass of material is proportional to the spontaneous fission rate. During the fission process, multiple neutrons are emitted within a very short time frame, that is, in coincidence. The number of neutrons emitted in coincidence determines the multiplicity of the event. The challenge is to determine the spontaneous fission rate from measured neutron multiplicity distributions. The authors initial work using multiplicity to solve accuracy problems in nuclear safeguards made use of an 8-channel multiplicity electronics package. Later a 32-channel version was developed and used for multiplicity detector design and assay investigations. But this too had insufficient multiplicity capacity to allow study of the desired range of sources without drastically reducing normal detector die-away times or efficiencies thereby increasing statistical counting errors. These unacceptable solutions drove the development of the current 256-channel multiplicity electronics design. This paper describes a prototype, 256-channel neutron-multiplicity-counting circuit. It is being used with a 4-MHz shift-register-based neutron coincidence circuit. The authors developed both circuits. They mount in a double-wide nuclear instrument module.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10175735
- Report Number(s):
- LA-UR-91-3571; CONF-911106-102; ON: DE93018565; TRN: 93:016793
- Resource Relation:
- Conference: 1991 Institute of Electrical and Electronic Engineers (IEEE) nuclear science symposium and medical imaging conference,Santa Fe, NM (United States),2-9 Nov 1991; Other Information: PBD: 1991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION
COUNTING CIRCUITS
DESIGN
PERFORMANCE TESTING
FISSILE MATERIALS
SAFEGUARDS
NEUTRON DETECTORS
MULTIPLICITY
NEUTRON DETECTION
COINCIDENCE CIRCUITS
MASS
SPONTANEOUS FISSION
RADIOASSAY
DIAGRAMS
440101
055001
GENERAL DETECTORS OR MONITORS AND RADIOMETRIC INSTRUMENTS
TECHNICAL ASPECTS