Response of GSO scintillator to thermal neutrons

A precise measurement was made to investigate the response of a cerium-doped GSO scintillator to thermal neutrons by means of a plastic scintillator as a neutron moderator. A delayed-coincidence technique with GSO-plastic scintillators was employed for discriminating gamma-rays. The technique was found to be very powerful in gamma-ray reduction. In the response spectrum, three sharp peaks were observed at 22, 83 and 190 keV. At 250–300 keV the response shows a small bump. This spectral structure was explained by low-lying levels of 156Gd and 158Gd. Moreover, the response was investigated in terms of time–strength interrelation.