Correlation Measurements with {sup 252}Cf to Characterize Fissile Material

Mattingly, J.K.

Oak Ridge National Laboratory

关键词: 46 Instrumentation Related To Nuclear Science And Technology;    Neutrons;    Frequency Analysis;    Fissile Materials;    11 Nuclear Fuel Cycle And Fuel Materials;   

DOI  :  10.2172/816191
RP-ID  :  ORNL/TM-2000/3
RP-ID  :  AC05-00OR22725
RP-ID  :  816191

美国|英语

来源: UNT Digital Library

【 摘 要 】

Measurements using {sup 252}Cf as a timed source of neutrons and gammas have in recent years undergone significant maturation. These methods use {sup 252}Cf as an observable source of spontaneous fission neutrons and gammas in conjunction with one or more neutron- and/or gamma-sensitive detectors to measure the time-distribution of correlated detector counts following (a) an observed {sup 252}Cf-fission event and/or (b) a counting event in another detector. Detection of {sup 252}Cf spontaneous fission is frequently achieved via use of a small ionization chamber in which the {sup 252}Cf is contained--in this case the timing of source emission events is random. However, one application subsequently described uses a neutron-absorbent ''shutter'' to modulate {sup 252}Cf emissions to produce a neutron source with deterministic timing. Other applications, frequently termed noise-analysis measurements, transform the time-distributions to the frequency domain. Collectively, these correlation methods use {sup 252}Cf to ''excite'' the fissile material and the response of the material is measured by an array of detectors and analyzed using standard time-correlation and/or frequency-analysis techniques. In recent years numerous advances have been made in the application of these methods to in-situ, or field measurements directed at characterizing various configurations of fissile material in operational facilities.