Design for shielding of acoustic neutrons measurements

The neutron fluence rates at different sites of the nuclear effect of acoustic cavitation (NEAC) lab were measured, and the site with less scattering neutrons was selected as the acoustic neutrons measuring point. Neutron shielding effects of different materials were simulated by SHIELD program. The 4 cm iron plate and 20 cm paraffin blocks were selected as optimum components for shadow shielding to reduce the neutron background. The scattering factor Fs of shadow shielding and shadow shielding combined with round shielding of BF3 proportional counter were measured. Besides, the statistically significant increase S.S.I≥3/√Fs was proposed as the criterion of statistically significant difference between counts of neutrons with and without cavitation. (authors)