Measurement of thermal neutron capture cross section of Ga with dual monitor foils and covariance analysis

Panikkath, P.*; Otsuka, Naohiko*; Iwamoto, Yosuke   ; Mohanakrishnan, P.*

The thermal neutron capture cross section of Ga was evaluated to be around 4.7 b in many nuclear data libraries. On the other hand, it was evaluated to be 3.71 b in JENDL-4.0. Since these cross section data were obtained by the activation measurement with a monitor foil to determine the absolute value of cross section, data depend on the monitor foil adopted in the measurement. In this work, we measured the thermal neutron capture cross section of Ga with a few monitor foils. In the experiment, neutrons decelerated in concrete shield were irradiated with a sample with Ga foil and Au and Mn monitor foils. A covariance analysis was performed to obtain the off-diagonal weighted mean of the results determined with the two monitor reactions. As a result, the thermal neutron capture cross section of Ga was 4.050.27 b and is close to the value of JENDL-4.0.