Transmission-based detection of nuclides with nuclear resonance fluorescence using a quasimonoenergetic photon source
Transmission-based detection of nuclides with nuclear resonance fluorescence using a quasimonoenergetic photon source
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DOI：
10.1063/1.3238328
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发表时间：
2009-10-15
影响因子：
3.2
通讯作者：
Tonchev, A. P.
中科院分区：
文献类型：
--
作者：
Hagmann, C. A.;Hall, J. M.;Tonchev, A. P.
我们对基于透射的同位素检测概念进行了详细的实验验证。此类系统中的主要背景过程是通过研究准单色（Delta E/E 类似于 3%）光子束对 (238)U 的检测来测量的。由于光子的优先衰减，在通过我们的测试物体传输的光谱中出现了一个凹口，该光子的能量可在 2 MeV 附近共振激发 (238)U 中的束缚核态。通过来自辅助 (238)U 目标的共振光子散射，在我们的测试对象下游测量了凹口。介绍了由于透射光束的放射性衰变和弹性散射而在陷波探测器中测量的主要背景。用非共振光子重新填充凹口的过程会使信号变得模糊，并导致假阴性的可能性更高。对再填充过程的测量产生了无效结果，并且我们报告了凹口填充因子大小的上限。 (C) 2009 年美国物理研究所。 [doi:10.1063/1.3238328]
We provide a detailed experimental validation of the concept of transmission-based isotope detection. The dominant background processes in this class of systems were measured by studying the detection of (238)U with a quasimonochromatic (Delta E/E similar to 3%) photon beam. A notch develops in the spectrum transmitted through our test objects due to the preferential attenuation of photons with an energy that resonantly excites a bound nuclear state in (238)U near 2 MeV. The notch was measured downstream of our test objects by means of resonant photon scattering from a secondary (238)U target. The dominant backgrounds measured in the notch detector due to radioactive decay and elastic scattering of the transmitted beam are presented. Processes that refill the notch with off-resonance photons will obscure the signal and result in a higher probability of false negatives. A measurement of the refill process produced a null result, and we report an upper limit on the magnitude of the notch fill factor. (C) 2009 American Institute of Physics. [doi:10.1063/1.3238328]