Nucleon-induced reactions at intermediate energies: New data at 96 MeV and theoretical status

Double-differential cross sections for light charged particle production (up to A=4) were measured in 96 MeV neutron-induced reactions, at TSL laboratory cyclotron in Uppsala (Sweden). Measurements for three targets, Fe, Pb, and U, were performed using two independent devices, SCANDAL and MEDLEY. The data were recorded with low energy thresholds and for a wide angular range (20-160 degrees). The normalization procedure used to extract the cross sections is based on the np elastic scattering reaction that we measured and for which we present experimental results. A good control of the systematic uncertainties affecting the results is achieved. Calculations using the exciton model are reported. Two different theoretical approches proposed to improve its predictive power regarding the complex particle emission are tested. The capabilities of each approach is illustrated by comparison with the 96 MeV data that we measured, and with other experimental results available in the literature.Comment: 21 pages, 28 figure

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

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

SCANDAL - a facility for elastic neutron scattering studies in the 50-130 MeV range

A facility for detection of scattered neutrons in the energy interval 50 130 MeV, SCAttered Nucleon Detection AssembLy (SCANDAL), has recently been installed at the 20-180 MeV neutron beam facility of The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on H-1 and C-12. In addition, the neutron beam facility is described in some detail. (C) 2002 Elsevier Science B.V. All rights reserved

Geometry and Energy-loss Features of Charged-particle Production in Fast-neutron Induced Reactions

Raw data reduction of charged particle production in fast neutron induced reactions must take into account specific characteristics of this type of experiment. A calculation procedure is presented which considers particular features such as: the thickness of targets, beam dimensions on the target, the beam profile, relative target-telescope angular position etc. It results in a simulation programme (Perten) of the experiment. The way the above mentioned particularities are considered, is exemplified in calculating solid angles and fractions of target producing charged particles with enough energy to be registered by the detector

Kerma values deduced from neutron-induced charged-particle spectra of carbon from 40 to 75 MeV.

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

Kerma values deduced from neutron-induced charged-particle spectra of carbon from 40 to 75 MeV.

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

Neutron-proton differential cross section measurements for E/sub n / from 28 to 75 MeV

Experimental measurements of differential cross-sections for neutron-proton scattering are reported for 12 incident neutron energies between 28 and 75 MeV. Data are compared with predictions of different theoretical models and with other experimental results.Anglai