Average neutron detection efficiency for DEMON detectors

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2013-05, Vol.709, p.68-71
• Main Authors: Zhang, S., Lin, W., Rodrigues, M.R.D., Huang, M., Wada, R., Liu, X., Zhao, M., Jin, Z., Chen, Z., Keutgen, T., Kowalski, S., Hagel, K., Barbui, M., Bonasera, A., Bottosso, C., Materna, T., Natowitz, J.B., Qin, L., Sahu, P.K., Schmidt, K.J., Wang, J.
• Format: Article
• Language: English
• Subjects: Intermediate heavy ion reactions; Neutron detector efficiency; Neutron multiplicity
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2013.01.039

The neutron detection efficiency of a DEMON detector, averaged over the whole volume, was calculated using GEANT and applied to determine neutron multiplicities in an intermediate heavy ion reaction. When a neutron source is set at a distance of about 1m from the front surface of the detector, the average efficiency, ϵav, is found to be significantly lower (20–30%) than the efficiency measured at the center of the detector, ϵ0. In the GEANT simulation the ratio R=ϵav/ϵ0 was calculated as a function of neutron energy. The experimental central efficiency multiplied by R was then used to determine the average efficiency. The results were applied to a study of the 64Zn+112Sn reaction at 40 A MeV which employed 16 DEMON detectors. The neutron multiplicity was extracted using a moving source fit. The derived multiplicities are compared well with those determined using the neutron ball in the NIMROD detector array in a separate experiment. Both are in good agreement with multiplicities predicted by a transport model calculation using an antisymmetric molecular dynamics (AMD) model code.