Neutron-induced Charged Particle Reactions Research Articles

Fast-neutron response of LaBr3(Ce) and LaCl3(Ce) scintillators

The response of LaBr3(Ce) and LaCl3(Ce) scintillators to fast neutrons is investigated. Neutron-induced charged-particle reactions are observed in both materials when exposed to the fast neutrons produced by an AmBe source, with pulse-shape discrimination used to separate channels. LaBr3(Ce) is found to have the best separation between reaction channels, while LaCl3(Ce) has a significantly higher efficiency.

New evaluation on angular distributions and energy spectra for neutron-induced charged-particle measurements

Recent development on neutron-induced charged particle reaction measurements can provide high-quality double differential cross sections at Los Alamos Neutron Science Center. With newly measured cross section data, we found lacking nuclear outputs for neutron-induced charged particle reactions in the latest ENDF/B-VIII.0 library, when compared with Monte Carlo simulations. This paper presents how we improved the missing angular distributions and energy spectra for these reactions and the validation of our new evaluations with the measurements performed with the LENZ instrument at LANSCE. The impact of this additional evaluation is demonstrated by comparing the MCNP simulations with the LENZ experimental data.

The characterization of 10B and 6LiF reference deposits by measurement of neutron-induced charged particle reactions — a second campaign

This paper describes the determination of the relative masses or relative areal densities of two new sets of reference deposits, prior to destructive analysis of subsets of these deposits by isotope dilution mass spectrometry and nondestructive analyses by other means. This work is a repeat of a previous effort of about five years ago. The goal of the present work is to improve the accuracy of the results to the level of one part per thousand. Improvements were attempted in several aspects of the measurements. The most significant improvement was realized simply by the increase in the number of repetitions of each measurement. In addition, a more extensive and elaborate data acquisition system was used, and an additional run-to-run monitor was employed to avoid possible problems related to the dependence of the 235U monitor on neutron temperature variations.

Differential cross-section measurements of the 2H(n, p)2n and 2H(n, d)n reactions and the n-n scattering length

A magnetic quadrupole triplet spectrometer has been constructed at Ohio University in order to study neutron-induced charged particle reactions. Using this spectrometer, the proton spectra at forward angles from the kinematically incomplete 2H(n, p)2n break-up reaction have been measured at E n = 11 and 25 MeV with experimental energy resolutions of 175 and 300 keV, respectively. The angular distributions of the 2H(n, d)n elastic scattering have also been measured at E n = 9 and 11 MeV. Theoretical calculations based on the Faddeev three-body formalism have been performed using rank-one separable S- and P-wave nucleon-nucleon interactions. Comparison of breakup calculations with the data is sensitive to the value of the neutron-neutron scattering length a nn, and supports the value a nn = −16.6 ± 0.4 obtained from kinematically complete experiments.

A versatile counter telescope for neutron-induced charged-particle reactions and finite geometry correction

An easily assembled counter telescope for neutron-induced charged particle reactions is described. The number and the dimensions of the proportional counters used for energy loss measurement can be easily changed, and either solid-state or CsI detectors incorporated as stopping detector. The telescope has been used successfully in 6 Li( n, z) and 9 Be( n, z) reactions after good pulse height resolution was obtained for the summed output of the proportional counters. The methods of calculation and program listing are given to determine the finite-geometry aperture function at any scattering angle, assuming the circular target and stopping detector are separated by an internal circular aperture with a smaller diameter.

Neutron-induced charged-particle reactions in 6Li and 9Be

Angular distributions of tritons from the 6Li(n, t) 4He reaction were measured at E n = 7.25, 6.77, 6.57, 5.24 and 4.71 MeV. Angular distributions of douterons from respectively, the 6Li(n, d) 5He two-body breakup reaction were measured at E n = 6.77 and 6.57 MeV, and of protons from the 6Li(n, p) 6He reaction at E n = 6.77, 5.24 and 4.71 MeV. All these reactions in 6Li were analyzed as direct interaction in the formalism of the distorted wave Born approximation. The optical model for the nuclear interaction was found to apply reasonably well to nuclei as light as 4He, 5He, 6He and 6Li. In addition, 6Li as an alpha-deuteron cluster gives the best bound-state wave function to describe the experimental angular distribution of tritons. The excitation functions at forward angles of the 6Li(n, t) 4He, 6Li(n, d) 5He and 6Li(n, p) 6He reactions were measured for incident neutron energies between 4.4 and 7.3 MeV. It is found that the 6Li(n, d) 5He two-body breakup reaction has a threshold at about E n = 5.3 MeV. Angular distributions at E n = 18.3 MeV for tritons and protons from the 9Be(n, t) 7Li and 9Be(n, p) 9Li, respectively, were also measured.

Neutron-Induced Charged Particle Reactions in Potassium-39

Neutron-Induced Charged Particle Reactions in Potassium-39

Neutron-Induced Charged Particle Reactions in Potassium-39

Thin thallium-activated potassium iodide crystals were exposed to monoenergetic neutrons ranging in energy from 2.0 to 5.5 Mev. Pulse-height spectra were taken of the scintillations in the crystal. Five charged particle groups were observed, three ($n, p$) reactions leading to states in ${\mathrm{A}}^{39}$, and two ($n, \ensuremath{\alpha}$) reactions leading to states in ${\mathrm{Cl}}^{36}$. A new level was discovered at 2.46\ifmmode\pm\else\textpm\fi{}0.1 Mev in ${\mathrm{A}}^{39}$, and the level at about 1.25 Mev in ${\mathrm{A}}^{39}$ confirmed. Yield curves were measured for three of the groups.