An absolute measurement of the efficiency of a BF3 proportional counter

摘要

We report an absolute measurement of the efficiency of a BF3 counter in narrow beam geometry in the energy range frame 0.024 eV to 0.111 eV. Agreement with calculated efficiency values is excellent. No significant end effects are noted. The basic feature of this experiment is the measurement of the incident neutron flux by gold foil activation and counting in an NaI well counter which was calibrated with gold foils irradiated in the National Bureau of Standards Standard Thermal Neutron Flux.