Preliminary Report on the Evaluation of an Electron-Positron Collider as a source of Monoenergetic Photons

Fast, James E. ; Campbell, Luke W.

Pacific Northwest National Laboratory (U.S.)

关键词: Power;    Shielding;    Stimulated Emission;    72 Physics Of Elementary Particles And Fields;    Equipment;   

DOI  :  10.2172/983736
RP-ID  :  PNNL-SA-70285
RP-ID  :  AC05-76RL01830
RP-ID  :  983736

美国|英语

来源: UNT Digital Library

【 摘 要 】

Abstract Active interrogation methods are being investigated to detect shielded special nuclear material (SNM). These approaches utilize either neutron or photon beams to excite the SNM in concert with either neutron or gamma ray detectors to observe the stimulated emissions. The two primary methodologies with photon beams are photofission and nuclear resonance florescence (NRF). Photofission requires photons energies of 7-10 MeV while NRF requires photon energies around 2 MeV. For both techniques, photons that are not in the appropriate energy band, e.g. the low energy tail of a Bremsstrahlung photon beam, contribute unwanted additional radiation dose to cargo. Typically less than 10% of the photons are in the usable energy band. The additional photon production generates a commensurate amount of additional radiation dose in the source and target areas, impacting shielding requirements and/or dose to operators and equipment and at the expense of a similar increase in power consumption. Hence it is highly desirable to produce narrow energy (“monoenergetic”) photon beams with tunable energy in the range of ~2-20 MeV.