Neutron Capture Cross Section Measurements of Nb-93, I-127, Ho-165, Ta-181 and U-238 between 3.2 and 80keV

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The neutron capture cross sections of ⁹³Nb, ¹²⁷I, ¹⁶⁵Ho, ¹⁸¹Ta and ²³⁸U were measured from 3.2 to 80keV using the time-of-flight method. The neutron beam was produced by the KURRI 46-MeV linear accelerator and capture γ-rays were detected by a C₆F₆ or C₆D₆ liquid scintillation detector. As the result of the use of a direct-coupled operational pre-amplifier, the detector recovered rapidly from the γ-flash such that data for higher energy neutrons can be obtained in spite of the short flight path of 11.7m. The neutron sensi-tivities of both detectors are compared and the superiority of the C₆D₆ detector is shown.
The experimental results of capture cross sections, corrected for resonance self-shield-ing and multiple scattering and normalized to the 24-keV absolute values, are shown numerically and graphically, and compared with other data. The agreement between the data is fairly good for ¹⁶⁵Ho and ²³⁸U, but not for ⁹³Nb, ¹²⁷I and ¹⁸¹Ta. The discrepancy between the data may be caused by the difference of the reference cross sections used for each experiment.