Neutron induced charged particle spectra and kerma from 25 to 60 MeV

Romero, J. L.; Brady, F.P.; Subramanian, T. S.

doi:10.1080/00337578608208347

Cited by 9 publications

(12 citation statements)

References 23 publications

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“…The only total kerma coefficients deduced on the basis of measured microscopic cross sections in Fig. 8, besides those of the present work, are indicated as full triangles at 60.7, 39.7, and 27.4 MeV incident neutron energies 24 and as reversed full triangle at 14.1 MeV. 46 All the other experimental data result from integral measurements [47][48][49][50][51][52][53][54][55][56][57][58][59] and they are in good or fair agreement with our results.…”

Section: Carbonmentioning

confidence: 50%

“…Open triangles at 60.7, 39.7, and 27.4 MeV represent total kerma coefficients deduced on the basis of experimental microscopic cross sections. 24 All the other experimental data in Fig. 10 are results of integral measurements.…”

Section: Oxygenmentioning

confidence: 99%

“…Nevertheless, the authors reported final total kerma coefficients based on their experimental microscopic cross sections at incident neutron energies of 60.7, 39.7, and 27.4 MeV. 24 Ample information exists in the lit-erature on total kerma coefficients obtained by integral measurements, covering a broad incident neutron energy range for many elements and composite materials ͑please see Ref. 25 and references therein͒.…”

Section: Introductionmentioning

confidence: 99%

“…Total kerma coefficients for various substances of radiological importance obtained according to mass fractions inTable I. To a variable extent in the incident neutron energy range some of the partial kerma coefficients contributing to the total are extrapolated ͑please seeTables III-V͒.measurements24 besides our data points are indicated as open triangles at 60.7, 39.7, and 27.4 MeV. Integral measurement results of Ref.…”

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Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

et al. 2000

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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.

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Section: Carbonmentioning

confidence: 50%

Section: Oxygenmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

et al. 2000

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“…Some of the measurements were integral kerma measurements of the same (or a similar) type as reported here (Goldberg et al 1978, DeLuca et al 1984 1985, Wuu and Milavickas 1987, McDonald and Cunnings 1988, Hartmann et al 1992a, b, Schuhmacher et al 1992, Schrewe et al 1995. Other kerma coefficients were derived from differential charged particle cross section measurements (Romero et al 1986, Dimbylow 1980, Slypen et al 1995. The kerma coefficients of Romero et al (1986) and Dimbylow (1980) were derived from the same set of experimental cross-section data (Brady and Romero 1979) but the authors applied different methods to supplement various non-measured kerma fractions.…”

Section: Carbonmentioning

confidence: 98%

Experimental kerma coefficients and dose distributions of C, N, O, Mg, Al, Si, Fe, Zr, A-150 plastic, Al₂O₃, AlN, SiO₂and ZrO₂for neutron energies up to 66 MeV

et al. 2000

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Low-pressure proportional counters (LPPCs) with walls made from the elements C, Mg, Al, Si, Fe and Zr and from the chemical compounds A-150 plastic, AlN, Al2O3, SiO2 and ZrO2 were used to measure neutron fluence-to-kerma conversion coefficients at energies up to 66 MeV. The LPPCs served to measure the absorbed dose deposited in the gas of a cavity surrounded by the counter walls that could be converted to the absorbed dose to the wall on the basis of the Bragg-Gray cavity theory. Numerically the absorbed doses to the walls were almost equal to the corresponding kerma values of the wall materials. The neutron fluence was determined by various experimental methods based on the reference cross sections of the 1H(n, p) scattering and/or the 238U(n, f) reactions. The measurements were performed in monoenergetic neutron fields of energies of 5 MeV, 8 MeV, 15 MeV and 17 MeV and in polyenergetic neutron beams with prominent peaks of energies of 34 MeV, 44 MeV and 66 MeV. For the measurements in the polyenergetic neutron beams, significant corrections for the contributions of the non peak energy neutrons were applied. The fluence-to kerma conversion coefficients of N and O were determined using the difference technique applied with matched pairs of LPPCs made from a chemical compound and a pure element. This paper reports experimental fluence-to-kerma conversion coefficient values of eight elements and four compounds measured for seven neutron energies, and presents a comparison with data from previous measurements and theoretical predictions. The distributions of the absorbed dose as a function of the lineal energy were measured for monoenergetic neutrons or, for polyenergetic neutron fields, deduced by applying iterative unfolding procedures in order to subtract the contributions from non-peak energy neutrons. The dose distributions provide insight into the neutron interaction processes.

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Kerma factors for calculating the absorbed dose of 15–150 MeV neutrons

Gorbatkov¹,

Kryuchkov²,

Sumaneev³

1996

At Energy

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The absorbed dose is the principal characteristic of the radiative interaction of ionizing radiation with matter. It is of special importance to be able to predict accurately its distribution in the biological tissue of patients undergoing a course of radiation therapy and also to determine the operating lifetime of the particle detectors and electronic equipment operating under conditions of a high radiation level.The absorbed dose of neutrons with energies lower than t00-150 MeV (D, GR) is calculated with satisfactory accuracy in the kerma approximationwhere F(E) is the fluence energy distribution in units of 1 cm-2.MeV -t , and k(E) is the kerma factor in units of 1 GR.cm 2.A large number of experimental and calculated data on the neutron kerma factors are presently known for the principal elements of tissue (see for instance [1]). Although the minimum error of the estimated kerma factors for energies in the region of 50 MeV for tissue elements is -20%, based on analyzing data from more than 20 studies, the real errors are considerably greater. In addition the errors increase as the neutron energy increases. It is therefore very important to improve the accuracy of the kerma factors for carbon, oxygen, and nitrogen.Data on kerma factors for the elements from which the particle detectors and electronics are composed are extremely scarce and their reliability is poor. At the same time, one of the main factors limiting the possibilities of operating the existing and planned apparatus is the change in the physical and chemical properties of their materials under the action of radiation. It is therefore an urgent problem in radiation physics to obtain information to enable one to predict, while still in the planning stage, the radiation loadings and service lifetimes of the experimental equipment. METHOD OF CALCULATIONThe kerma factor is defined as the sum of the initial kinetic energy of the charged particles created in elastic and inelastic interactions of a neutron with a nucleus, normalized to unit mass of the substance and unit fluence.Elastic scattering introduces an important contribution to the kerma factor for light isotopes and for neutron energies below 70 MeV. For example, in the case of carbon and for E n = 20 MeV it constitutes about 25%. In the work now presented the elastic scattering component for the kerma factor was taken into account for neutron energies below 70 MeV. (In the case of hydrogen the kerma factor is completely determined by elastic scattering, independently of the neutron energy.) The recoil energy of the nuclei was calculated from the well-known kinematic relationships, taking account of their angular distributions defined in terms of the Glauber model. The cross sections for the elastic scattering of neutrons by different nuclei were taken from the Sadko-2 library of nuclear data [2]. However, in the investigated range of energies the kerma factors for all nuclei with the exception of hydrogen are determined by inelastic scattering.The kerma factors for neutrons of energy less tha...

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Neutron induced charged particle spectra and kerma from 25 to 60 MeV

Abstract: Neutron beams in the tens of MeV range are widely used in biomedical applications.

Cited by 9 publications

References 23 publications

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

Experimental kerma coefficients and dose distributions of C, N, O, Mg, Al, Si, Fe, Zr, A-150 plastic, Al₂O₃, AlN, SiO₂and ZrO₂for neutron energies up to 66 MeV

Kerma factors for calculating the absorbed dose of 15–150 MeV neutrons

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Neutron induced charged particle spectra and kerma from 25 to 60 MeV

Abstract: Neutron beams in the tens of MeV range are widely used in biomedical applications.

Cited by 9 publications

References 23 publications

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

Experimental kerma coefficients of biologically important materials at neutron energies below 75 MeV

Experimental kerma coefficients and dose distributions of C, N, O, Mg, Al, Si, Fe, Zr, A-150 plastic, Al2O3, AlN, SiO2and ZrO2for neutron energies up to 66 MeV

Kerma factors for calculating the absorbed dose of 15–150 MeV neutrons

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Product

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Experimental kerma coefficients and dose distributions of C, N, O, Mg, Al, Si, Fe, Zr, A-150 plastic, Al₂O₃, AlN, SiO₂and ZrO₂for neutron energies up to 66 MeV