Measurement of Neutron Kerma Factors for Carbon and A-150 Plastic At Neutron Energies of 26.3 Mev and 37.8 Mev

Kerma factors for carbon and A-150 tissue equivalent plastic were determined in two nearly monoenergetic neutron beams. Kerma was measured with low pressure proportional counters (PCs) with walls made of graphite and A-150 plastic. The neutron fluence was measured with a proton recoil telescope. The corrections for the kerma contributions from low energy neutrons in the beams were determined by time-of-flight measurements with an NE213 scintillation detector and with the Pcs. For neutron energies of (26.3+/-2.9) MeV and (37.8+/-2.5) MeV the kerma factors for carbon were (35.5+/-3.0) pGy cm2 and (42.6+/-3.9) pGy cm2, respectively, and for A-150 they were (75.6+/-5.4) pGy cm2 and (79.0+/-5.6) pGy cm2. At these energies the kerma factor ratio for ICRU muscle tissue to A-150 calculated on the basis of the new kerma factors, is 0.93

Quasi-monoenergetic neutron beams with energies from 25 to 70 MeV

Quasi-monoenergetic neutron beams in the energy range from about 25 to 70 MeV have been produced and accurately characterised at the accelerator facility of the Universite Catholique de Louvain (UCL), Belgium. The neutron fluence was determined with a proton recoil telescope and a liquid scintillation detector (NE213). The spectral fluence was measured employing the time-of-flight method with the NE213 detector and a U-238 fission ionisation chamber. The results obtained with the different methods are in agreement within the respective uncertainties. (C) 1999 Elsevier Science B.V. All rights reserved