Light Charged Particle Production Research Articles

Proton Energy Spectra From Deuteron Induced Reaction on Copper At 14,5 MeV Deuteron Energy

Double differential cross sections have been measured for light-charged particle production in deuteron-induced reactions on nat Cu at incident energies of 14.5 MeV. The experiment was performed at the isochronous cyclotron of the Institute of Nuclear Physics (Kazakhstan). Charged particles were detected using a set of Si and CsI detectors from 30° to 135°, by step of 15°. The integral cross-sections were determined by integrating over the angle the double differential cross-sections. Double differential and integral charged particle emission cross-sections have been calculated by the TALYS 1.9 nuclear reaction which code based on a modified version of the exciton model of the pre-equilibrium nuclear decay. Direct, compound, and pre-equilibrium reaction contributions have been determined for the emission of proton particles.

Double differential cross sections of light charged particle production for the n+238U reaction**Supported by National Natural Science Foundation of China-NSAF (U1630122), IAEA Coordinated Research Projects (CRPs) on Recommended Input Parameter Library (RIPL) for Fission Cross Section Calculations (20464) and Science Challenge Project (TZ2018005)

Production of light complex particles from the n+238U reaction is analyzed with the exciton model including the improved Iwamoto-Harada pickup mechanism for the preequilibrium process. It is allowed that some of the nucleons forming the complex ejectile come from levels below the Fermi energy, and the intrinsic structure of the emitted particle is taken into account. The equilibrium-state emissions are also considered by using Hauser-Feshbach theory with the width fluctuation correction and the evaporation model. Moreover, all cross sections, angular distributions, energy spectra and double differential cross sections of neutron, proton, deuteron, triton and alpha emissions for the n+238U reaction are consistently calculated and analyzed with nuclear theoretical models in the energy range En ⩽ 150 MeV. ENDF-formatted nuclear data including information about the production of light charged particles are obtained.

Pulse shape discrimination of plastic scintillator EJ 299-33 with radioactive sources

The present study has been carried out in order to investigate about the possibility of using EJ 299-33 scintillator in a multi-detector array to detect neutrons along with light charged particles. In a reaction induced by stable and exotic heavy-ions beams, where copious production of neutrons and other light charged particles occurs, discrimination with low identification threshold of these particles are of great importance. In view of this, EJ 299-33 scintillator having dimension of 3 cm × 3 cm × 3 cm backed by a photomultiplier tube was tested and used under vacuum to detect neutrons, gamma-rays and alpha particles emitted by radioactive sources. Anode pulses from the photomultiplier tube were digitized through GET electronics, recorded and stored in a data acquisition system for the purpose of an off-line analysis. The measurements, under vacuum and low background conditions, show good pulse shape discrimination properties characterized by low identification threshold for neutrons, gamma-rays and alpha particles. The Figures of Merit for neutron-gamma and alpha particles-gamma discriminations have been evaluated together with the energy resolution for gamma-ray and alpha particles.

Evaluation of A-dependence of cross-sections for light charged particle production in proton induced reactions at intermediate energies

Abstract Proton-, deuteron-, triton-, 3He, and α-particle production cross-sections were evaluated for proton induced reactions for 278 stable target nuclei with an atomic number from 3 to 83 for a number of incident proton energies from 62 to 1200 MeV using available experimental data and results of model calculations. Data obtained can be used for the evaluation of gas production cross-sections and gas production rates in reactions induced by intermediate energy protons. An example of the use of the data is given for 9Be(p,x) reactions.

Role of model ingredients in the production of light particles and entropy

We study the role of different entrance channels and model ingredients on the composite particle yield ratios and entropy production. We find that the composite particle yield ratios show some sensitivity towards equation of state. The Gaussian width of the nucleons affects the production of light charged particles significantly.

Zero-degree measurements ofC12fragmentation at 95 MeV/nucleon on thin targets

During therapeutic treatments using ions such as carbon, nuclear interactions between the incident ions and nuclei present in organic tissues may occur, leading to the attenuation of the incident beam intensity and to the production of secondary light charged particles. As the biological dose deposited in the tumor and the surrounding healthy tissues depends on the beam composition, an accurate knowledge of the fragmentation processes is thus essential. In particular, the nuclear interaction models have to be validated using experimental double differential cross sections which are still very scarce. An experiment was realized in 2011 at GANIL to obtain these cross sections for a 95-MeV/nucleon carbon beam on different thin targets for angles raging from 4${}^{\ensuremath{\circ}}$ to 43${}^{\ensuremath{\circ}}$. To complete these data, a new experiment was performed in September 2013 at GANIL to measure the fragmentation cross section at zero degree for a 95-MeV/nucleon carbon beam on thin targets. In this work, the experimental setup will be described, the analysis method detailed, and the results presented.

Dependence and Influence of Projectile Energy and Target Mass on the Production of Light Charged Particles and Intermediate Mass Fragments in Proton Induced Reactions

Calculations were performed for proton induced spallation reactions over a wide range of atomic masses on the targets: 12C, 27Al, natNi, 108Ag and 197Au using an Intra-nuclear Cascade Model (INCL4.6) with coalescence which includes the emission of protons, light clusters (d–4He), and intermediate mass fragments (up to A=8) formed by the nucleons during the first stage of the reaction. The emission of particles from excited cascade residua are described using three different theoretical models SMM, ABLA07, and GEMINI++. A comparison of calculations with experimental double differential cross–sections d2σ/dΩdE for light charged particles and selected intermediate mass fragments was studied at proton beam energies from 1.2−2.5 GeV. Systematic deviations of the simulated cross sections from the experimental data were found for both light charged particles and intermediate mass fragments.

Nuclear data measurements at the new NFS facility at GANIL

The NFS (Neutrons For Science) facility is part of the SPRIAL 2 project at GANIL, Caen, France. The facility is currently under construction and the first beam is expected in early 2013. NFS will have a white neutron source covering the 1–40 MeV energy range with a neutron flux higher than comparable facilities. A quasi-mono-energetic neutron beam will also be available. In these energy ranges, especially above 14 MeV, there is a large demand for neutron-induced data for a wide range of applications involving dosimetry, medical therapy, single-event upsets in electronics and nuclear energy. Today, there are a few or no cross section data on reactions such as (n, fission), (n, xn), (n, p), (n, d) and (n, α). We propose to install experimental equipment for measuring neutron-induced light-charged particle production and fission relative to the H(n, p) cross section. Both the H(n, p) cross section and the fission cross section for 238U are important reference cross sections used as standards for many other experiments. Nuclear data for certain key elements, such as closed shell nuclei, are also of relevance for the development of nuclear reaction models. Our primary intention is to measure charged particle production (protons, deuterons and alphas) from 12C, 16O, 28Si and 56Fe and neutron-induced fission cross sections from 238U and 232Th.

Study of Light Charged Particle Production Double Differential Cross Sections from Proton-Actinide Reactions at 360 MeV

Study of Light Charged Particle Production Double Differential Cross Sections from Proton-Actinide Reactions at 360 MeV

Improved modelling of helium and tritium production for spallation targets

Reliable predictions of light charged particle production in spallation reactions are important to correctly assess gas production in spallation targets. In particular, the helium production yield is important for assessing damage in the window separating the accelerator vacuum from a spallation target, and tritium is a major contributor to the target radioactivity. Up to now, the models available in the MCNPX transport code, including the widely used default option Bertini–Dresner and the INCL4.2–ABLA combination of models, were not able to correctly predict light charged particle yields. The work done recently on both the intranuclear cascade model INCL4, in which cluster emission through a coalescence process has been introduced, and on the de-excitation model ABLA allows correcting these deficiencies. This paper shows that the coalescence emission plays an important role in the tritium and 3 He production and that the combination of the newly developed versions of the codes, INCL4.5–ABLA07, now lead to good predictions of both helium and tritium cross-sections over a wide incident energy range. Comparisons with other available models are also presented.

Competition of coalescence and “fireball” processes in nonequilibrium emission of light charged particles fromp+Aucollisions

The energy and angular dependence of the double differential cross sections ${d}^{2}\ensuremath{\sigma}/d\ensuremath{\Omega}\mathit{dE}$ were measured for $p,d,t,$$^{3,4,6}\mathrm{He}$, $^{6,7,8,9}\mathrm{Li}$, $^{7,9,10}\mathrm{Be}$, and $^{10,11,12}\mathrm{B}$ isotopes produced in reactions of 1.2- and 1.9-GeV protons on a Au target. The beam energy dependence of the data, supplemented by the cross sections from a previous experiment at 2.5 GeV, is very smooth. The shape of the spectra and angular distributions do not change significantly in the beam energy range from 1.2 to 2.5 GeV. However, the absolute value of the cross sections increases for all ejectiles. The intermediate mass fragment spectra and their angular distributions are very well reproduced by a phenomenological model of two emitting, moving sources, with parameters smoothly varying with energy. The double differential cross sections for light charged particles were analyzed in the framework of the microscopic model calculations of intranuclear cascade, including the coalescence of nucleons and a statistical model for evaporation of particles from excited residual nuclei. However, the energy and angular dependencies of the data agree with neither predictions of the microscopic intranuclear cascade calculations for protons nor the coalescence calculations for other light charged particles. A very good description of the data is achieved by the phenomenological inclusion of the emission of light charged particles from a ``fireball'' (i.e., a fast and hot moving source). It was found that the nonequilibrium processes are very important for the production of light charged particles. They exhaust 40%--80% of the total cross section---depending on the emitted particles. Coalescence and fireball emission yield comparable contributions to the cross sections with the exception of the $^{3}\mathrm{He}$ data where coalescence clearly dominates. For all light charged particles, the ratio of nonequilibrium processes to processes proceeding through a phase of statistical equilibrium does not change significantly between the beam energies of 1.2 and 2.5 GeV.

Light charged-particle production in 96 MeV neutron-induced reactions on carbon and oxygen

In recent years, an increasing number of applications involving fast neutrons have been developed or are under consideration, e.g. radiation treatment of cancer, neutron dosimetry at commercial aircraft altitudes, soft-error effects in computer memories, accelerator-driven transmutation of nuclear waste and energy production and determination of the response of neutron detectors. Data on light-ion production in light nuclei such as carbon, nitrogen and oxygen are particularly important in calculations of dose distributions in human tissue for radiation therapy at neutron beams, and for dosimetry of high-energy neutrons produced by high-energy cosmic radiation interacting with nuclei (nitrogen and oxygen) in the atmosphere. When studying neutron dose effects, it is especially important to consider carbon and oxygen, since they are, by weight, the most abundant elements in human tissue. Preliminary experimental double-differential cross sections of inclusive light-ion (p, d, t, (3)He and alpha) production in carbon induced by 96-MeV neutrons have been presented. Energy spectra were measured at eight laboratory angles: 20, 40, 60, 80, 100, 120, 140 and 160 degrees. Measurements were performed at The Svedberg Laboratory (TSL), Uppsala, using the dedicated MEDLEY experimental setup. The authors have earlier reported experimental double-differential cross sections of inclusive light-ion production in oxygen. In this paper, the deduced kerma coefficients for oxygen has been presented and compared with reaction model calculations.

Magnitude factor systematics of Kalbach phenomenology for reactions emitting helium and lithium ions

We investigated the magnitude factor of the Kalbach phenomenology in order to estimate double differential cross-sections (DDXs) of ( p , 3He), ( p , 4He), ( p , 6Li) and ( p , 7Li) reactions at intermediate energies that is several hundreds of MeV. Firstly, we obtained DDXs on target nuclei, Be, C and Al by using a 392-MeV proton beam. Secondly, the magnitude factor has been formulated and parameterized by using the present data and Ag data measured elsewhere. Although the slope parameters of the magnitude factor were found to be independent of targets, absolute values are dependent. The magnitude factor shows a consistency between heavy targets, Al and Ag. In contrast, considerable different tendencies are seen for the light targets. As a result, it has been remarked that the present parameterization is of highly useful in yield estimation for experimental planning of light charged particle production reactions. It allows us to conduct such experiments with the higher efficiency.

Light charged particle and neutron production in proton- and α-particle-induced reactions on natSi at energies between 20 and 65 MeV

Inclusive cross sections ( d 2 σ d Ω d E , d σ d E , d σ d Ω and σ T ) for the production of neutron and light charged particles induced by protons of 26.5, 48.5 and 62.9 MeV and alpha-particles of 25.4, 45.5 and 57.8 MeV on natSi targets have been measured. The secondary particles ( p, d, t, 3He, α, 6Li, 7Li and 7Be) were detected at angles from 10° to 165° in steps of ±10° with respect to the beam axis. Neutrons emitted in these reactions were only recorded in coincidence with, at least, one detected light charged particle. A comparison of the proton- and neutron-induced reactions on Si at E = 62 MeV shows evidence of charge independence of the nuclear force. The proton spectra from the two reactions scale as expected from the difference in proton–neutron and proton–proton quasi-free scattering cross sections. The new data are reproduced with moving source fits and are also compared with state-of-the-art nuclear reaction models. The codes used for this purpose, GNASH and TALYS, consider direct nuclear reactions as well as pre-equilibrium and compound nucleus emission, and were found to reproduce the general features of the experimental data, especially for the ( p , p x ) channel. More detailed comparisons with the data indicate that there is still room for improvement in these codes.

Microscopic studies of light charged particles and neutron productions in natSi using proton and alpha beams of energies between 20 and 65 MeV

Inclusive cross sections (d2σ, dΩdE, dσdE, dσdΩ and σT) for the production of light charged particles induced by protons of 26.5, 48.5 and 62.9 MeV and alpha-particles of 25.4, 45.5 and 57.8 MeV on natSi targets have been measured. The secondary emitted particles (p, d, t, 3He, α, 6Li, 7Li and 7Be) were detected at angles from 10° to 165° in steps of ±10° with respect to the beam axis. Neutrons emitted in these reactions were only recorded in coincidence with, at least, one detected light charged particle. The measurements were compared with all available published data from similar or comparable reactions and with theoretical calculations based on the GNASH and TALYS nuclear-reaction codes.

Light charged-particle production from proton- and α-induced reactions onnatSi at energies from 25 to 65 MeV: A theoretical analysis

Proton- and \ensuremath{\alpha}-induced reactions on ${}^{\mathrm{nat}}$Si have been studied in the energy range from 25 to 65 MeV at the Louvain-la-Neuve cyclotron facility. The measured double-differential cross sections and angle-integrated energy spectra for the production of light charged particles (p, d, t, $^{3}\mathrm{He}$, \ensuremath{\alpha}) have been compared with the predictions of the nuclear-reaction code TALYS. A full description of the contributing reaction mechanisms is presented, and possible improvements to the calculations are discussed.

Neutron-induced light charged particle production in carbon at 96 MeV

Differential cross sections of charged particle production, i.e., p, d, t, 3He-ions and α-particles, in 96 MeV neutron–carbon interactions have been measured at laboratory angles in the range 20° to 160° in steps of 20°. The experimental techniques are described as well as the procedures for acquisition, analysis, reduction and correction of the data. Results including double differential, energy-differential, angle-differential and total particle production cross sections are reported and constitute the first data set with five ejectiles at such a high neutron energy. Thanks to the low-energy thresholds, 50% of the production cross section of α-particles, and 85% of the production cross sections of protons and deuterons, could be measured. For α-particles, the measured fraction is much higher than what has been achieved earlier at lower energies. The results on the hydrogen isotopes agree fairly well with a previous measurement at 95 MeV and with recent GNASH calculations. For the helium isotopes, however, there are important discrepancies in spectral shape and magnitude between the new results and the model calculations.

Nucleon-induced reactions at intermediate energies: New data at96MeVand 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.

JAERI-Universities Joint Research Project on Radiation Safety in Proton Accelerator Facilities

JAERI-Universities Joint Research Project has been carried out since 2000 in order to study the radiation safety in high-energy proton accelerator facilities. Eight research groups joined in the project to tackle three major subjects, using a quasi-monoenergetic neutron field at TIARA facility of JAERI. Cross section data of elastic scattering and light charged particle production were measured for several tens MeV neutrons incident to the elements composing the human tissue. Absorbed dose distributions in a PMMA phantom were measured to verify the results calculated by some radiation transport codes. A rem counter-type monitor with a lead breeder layer within its moderator was tested in 40-70 MeV neutron fields. A new method of dose measurement for neutrons with energies from a few MeV to 100 MeV has been developed applying the spectrum weighted function to a liquid organic scintillator. The energy response of neutron track detector and superheated drop detector was examined to develop a neutron dosimeter that is applicable to the energy region more than 20 MeV. In the study on internal dosimetry for airborne radionuclides, particle size distribution of radioactive aerosols and chemical forms of radioactive gases in the air were measured for irradiation of several tens MeV neutrons.

Light charged particle production in the interaction of fast neutrons (25–65 MeV) with uranium nuclei

Energy spectra (double-differential cross sections) for proton, deuteron, triton, and \ensuremath{\alpha}-particle production in fast neutron induced reactions on uranium are reported for several incident neutron energies between 25 and 65 MeV. The spectra were obtained at nine laboratory angles between $20\ifmmode^\circ\else\textdegree\fi{}$ and $160\ifmmode^\circ\else\textdegree\fi{}$ and extrapolated and interpolated to other ten angles suitably covering the laboratory angular domain of $0\ifmmode^\circ\else\textdegree\fi{}$ to $180\ifmmode^\circ\else\textdegree\fi{}.$ The experimental setup and procedures for data reduction including corrections and normalization are presented and discussed. Based on the obtained double-differential cross sections, energy-differential and total cross sections are deduced as well. Theoretical calculations are based on GNASH and TALYS nuclear reaction codes which integrate the optical model, direct, preequilibrium, fission, and statistical nuclear reaction models in one calculation scheme.