Initial Design Calculations for a Detection System that will Observe Resonant Excitation of the 680 keV state in 238U

Pruet, J. ; Hagmann, C.

Lawrence Livermore National Laboratory

关键词: De-Excitation;    Probability;    Light Sources;    Photons;    Excitation;   

DOI  :  10.2172/902615
RP-ID  :  UCRL-TR-227910
RP-ID  :  W-7405-ENG-48
RP-ID  :  902615

美国|英语

来源: UNT Digital Library

【 摘 要 】

We present calculations and design considerations for a detection system that could be used to observe nuclear resonance fluorescence in {sup 238}U. This is intended as part of an experiment in which a nearly monochromatic beam of light incident on a thin foil of natural uranium resonantly populates the state at 680 keV in {sup 238}U. The beam of light is generated via Compton upscattering of laser light incident on a beam of relativistic electrons. This light source has excellent energy and angular resolution. In the current design study we suppose photons emitted following de-excitation of excited nuclei to be observed by a segmented array of BGO crystals. Monte Carlo calculations are used to inform estimates for the design and performance of this detector system. We find that each detector in this array should be shielded by about 2 cm of lead. The signal to background ratio for each of the BGO crystals is larger than ten. The probability that a single detector observes a resonant photon during a single pulse of the light source is near unity.