Radiation Dosimetry of a graphite Moderated Radium-Beryllium Source

摘要

The Brookhaven Nationa Laboratory Sigma Pile a Radium-Beryllium neutron source imbedded in a cube of graphite blocks. The pile is approximately 2.13 m on four sides and is 3.07 m high. Absolute and relative thermal neutron flux measurements have been made using gold and indium foils, which were both bare and cadmiw covered. Thermo-luminescent dosimeters were used to determine the neutron and gamma-ray dose rates in the pile. Gamma-ray dose rate measurements have also been made in the air outside of the pile, while the Radium-Beryllium neutron source was being withdrawn from the pile. The Monte Carlo MCNP code has been used to calculate the coupled neutron-photon &ort, Measured dose rates at various locations agreed with the calculated values within 5% to 15%.