Cryogenic transmission nuclear resonance fluorescence using laser Compton scattering gamma rays

静間 俊行*; Omer, M.; 羽島 良一*; 小泉 光生; Zen, H.*; 大垣 英明*; 平 義隆*

no journal, , 

Nuclear resonance fluorescence (NRF) is a process in which atomic nuclei absorb and emit gamma rays. Because the emitted gamma rays have energies specific to each nuclide, it is possible to identify the nuclide by measuring the energy of emitted NRF gamma rays. In transmission NRF, a gamma-ray beam that passes through an absorption target is irradiated to another target (called witness plate, WP) which consists of the same nuclide as the absorption target, and NRF gamma rays emitted from the WP target are measured. The absorption amount of gamma rays in transmission NRF depends on the temperature of absorption and WP targets due to the Doppler broadening of resonant width. Therefore, the temperature of the absorption or WP targets may affect the time and sensitivity of the measurement. To study the temperature dependence of the self-absorption, we irradiated Pb-206 samples at room or LN2 temperatures with a laser Compton scattering (LCS) gamma-ray beam at the ultraviolet synchrotron orbital radiation (UVSOR)-III facility, National Institutes of Natural Sciences Institute for Molecular Science. We will present the experimental technique of transmission NRF and the results of the measurements. This work is a contribution to the International Atomic Energy Agency under the coordinated research program, J02015 (Facilitation of Safe and Secure Trade Using Nuclear Detection Technology - Detection of RN and Other Contraband).