Towards a Metric to Estimate Atomic Number from Backscattered Photons
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.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 967282
- Report Number(s):
- LLNL-TR-415801
- Country of Publication:
- United States
- Language:
- English
Similar Records
Testing the photon--photon sector of quantum electrodynamics with free-electron lasers
Energy spectra of electrons and positrons produced in semi-infinite and infinite water phantoms irradiated by photons with energies up to 1 GeV