Measurement of the effective neutron capture cross section of cesium-134 by triple neutron capture reaction method

The measurement of effective neutron capture cross section(delta) of Cs-134 was carried out with a method using a triple neutron capture reaction, Cs- 133(n, gamma)Cs-134(n, gamma)Cs-135(n, gamma)Cs-136. The target used for th e experiment was natural cesium(Cs-133), and was irradiated for 23 days and 17 hours in the reactor JRR-3 at Japan Atomic Energy Research Institute(JA ERI). The neutron field of the reactor was monitored by Au/Al and Co/Al all oy wires. A high purity Ge detector was employed for the measurement of gam ma-rays from the irradiated target and monitor wires. Gamma-rays emitted in the decay of Cs-134 and Cs-136 nuclides induced by single and triple neutr on capture reactions of 133Cs were seen at the energies of 563, 569; 605, 7 96, 802: 819: 1,039, 1,048, 1,168 and 1,235 keV. Decays of the 819 and the 1,045 keV gamma-ray intensities were followed; it was confirmed that these gamma-rays originated in the Ba-136, the decay product of Cs-136. Data obta ined were analyzed with values of neutron capture cross sections of Cs-133 and Cs-135. The delta of Cs-134 Obtained is 140.6+/-8.5 hams and agrees wit h the value measured by Bayly et al. with a mass analysis method within the limits of error.