Towards a Metric to Estimate Atomic Number from Backscattered Photons

Walston, S ; Dietrich, D ; Wurtz, R

关键词: ANNIHILATION;    ATOMIC NUMBER;    CARGO;    COMPTON EFFECT;    CONTAINERS;    METRICS;    PAIR PRODUCTION;    PHOTONS;    POSITRONS;   

DOI  :  10.2172/967282
RP-ID  :  LLNL-TR-415801
PID  :  OSTI ID: 967282
Others  :  TRN: US0904439

学科分类：核物理和高能物理

美国|英语

来源: SciTech Connect

【 摘 要 】

An ability to determine the atomic number of a material in a cargo container would be helpful in interdicting smuggled nuclear materials. This paper examines two processes by which high energy photons interact with matter; Compton scattering and pair production. The ratio of the number of photons which originate from the annihilation of positrons resulting from pair production and the number of photons coming from Compton scattering gives a good indication of atomic number. At large angles relative to an incident beam - i.e. backscattered, there is good separation in energy between Compton scattered photons and photons from positron annihilations. This ratio can then be cleanly determined in order to estimate atomic number.