ABSTRACT
The present work summarizes our results already published on cross sections and partial kerma coefficients for hydrogen, carbon, and oxygen and then applies them for determining experimental partial and total kerma coefficients of composite biologically important materials. Double-differential cross sections for light-charged particle production (proton, deuteron, triton, and alpha particle) induced by fast neutrons on hydrogen, carbon, and oxygen have been experimentally measured at several incident energies from 25 to 75 MeV. The measurements covered the laboratory angular range 20 degrees to 160 degrees and were extended to very forward and very backward angles by using a reliable extrapolation procedure. Energy-differential, angle-differential, and total production cross sections were derived from the measured data. The experimental methods and data reduction procedures are briefly presented here. The experimental cross sections were compared to existing data in the literature for nucleon-induced reactions and against prediction of nuclear models. Partial and total elemental kerma coefficients were deduced on the basis of the measured cross sections. Procedures for extrapolating the partial kerma coefficients down to the reaction threshold energies for each of the measured ejectile species have been applied to carbon and oxygen. A simple-to-use analytical formula to describe the experimental hydrogen kerma coefficients was proposed which provides the recoil kerma coefficients in the incident neutron energy range 0.3 to 100 MeV. The present article reports for the first time experimental partial kerma coefficients for composite materials of biological interest. Resulting total kerma coefficients are compared to theoretical predictions and to other experimental data.
Subject(s)
Neutrons , Radiotherapy/instrumentation , Algorithms , Carbon , Cyclotrons , Hydrogen , Models, Statistical , Oxygen , Plastics , Reference Values , WaterABSTRACT
The double-differential cross sections for proton, deuteron, triton and alpha particle production in fast neutron induced reactions on carbon have been measured at several neutron energies from 25 to 75 MeV in the angular range from 20 degrees to 160 degrees. Experimental energy-differential, angle-differential and total cross sections are deduced, and consequently the partial and total kerma coefficients. The obtained experimental partial kerma coefficients are extrapolated down to the threshold energy of each measured reaction channel. Results on the experimental double differential, energy-differential and total cross sections are briefly presented. The deduced partial and total kerma coefficients of the present work are compared with previous measurements and theoretical predictions.
Subject(s)
Carbon , Fast Neutrons , Alpha Particles , Cyclotrons , Models, Theoretical , Protons , Scattering, RadiationABSTRACT
For nine incident neutron energies in the range 25 to 65 MeV, the double-differential cross sections (energy spectra) for the (n, px), (n, dx), (n, tx) and (n, alpha x) reactions on aluminium have been measured at lab angles between 20 degrees and 160 degrees in steps of 10 degrees. The partial and total kerma coefficients have been determined from the experimental energy-differential cross sections. The resulting partial kerma coefficients for the incident neutron energy range of 25-65 MeV are extrapolated to the threshold energy of each registered reaction product type. Only illustrative results of the experimental double-differential, energy-differential and total cross sections are presented. The deduced partial and total kerma coefficients of the present work are compared with results of previous integral measurements and theoretical predictions.
Subject(s)
Aluminum , Fast Neutrons , Energy TransferABSTRACT
Hydrogen kerma factors and their uncertainties are deduced on an experimental basis, starting from our previously measured differential cross sections completed with available data from the literature, in the incident neutron energy range 25 to 75 MeV. The deduced experimental kerma factors are compared with theoretical predictions. A simple to use parametrization of the hydrogen kerma factor values in the incident neutron energy range 0.3 to 100 MeV is also proposed.
Subject(s)
Fast Neutrons , Hydrogen , Scattering, RadiationABSTRACT
The double-differential cross sections (energy spectra) for the (n, px), (n, dx), (n, tx) and (n, rx) reactions on oxygen have been measured for nine incident neutron energies in the range 25 to 65 MeV at lab angles between 20 degrees and 160 degrees in steps of 10 degrees. From these measurements, the energy differential cross sections have been determined and consequently the partial and total kerma factors. Based on the obtained experimental partial kerma factors in the incident neutron energy range 25-65 MeV, a procedure is proposed for the extrapolation of these values to the reaction threshold energy of each measured reaction channel. Results of the experimental double-differential, energy differential and total cross sections are presented. The deduced partial and total kerma factors of the present work are compared with results of previous measurements and theoretical predictions.
Subject(s)
Fast Neutrons , Neutron Capture Therapy , Oxygen , Alpha Particles , Data Interpretation, Statistical , Deuterium , Mathematics , ProtonsABSTRACT
The double-differential cross-sections for the 12C(n, px), 12C(n, dx), 12C(n, tx) and 12C(n, alpha x) reactions have been measured at three incident neutron energies, 42.5, 62.7 and 72.8 MeV, at laboratory angles between 20 degrees and 160 degrees. From these measurements, the energy-differential cross-sections have been determined and consequently the partial and total kerma values. Results of the experimental double-differential and energy-differential cross-sections at the three incident neutron energies are presented. The deduced kerma values are compared with previous measurements and theoretical predictions.