Intranuclear Cascade Model Research Articles

A direct probe of Λ potential in nuclear medium

Using the Liège intranuclear-cascade model together with the ablation model ABLA, an investigation is conducted into the effects of Λ potential in Λ-nucleus and Λ-hypernucleus-nucleus collisions across various beam energies. The findings show that the angle and transverse-momentum distributions of scattered Λ hyperon, the scattering cross section of the Λ hyperon in Λ-nucleus collisions as well as the rapidity distribution of Λ hyperon in Λ-hypernucleus-nucleus collisions are significantly influenced by the strength of the Λ potential in these scattering reactions across various beam energies. These demonstrations, unhindered by the uncertainties of Λ and hypernuclei productions in nuclear medium, allow for a direct investigation of the Λ potential, especially its momentum dependence. The criticality of probing the Λ potential is closely associated with the resolution of the “hyperon puzzle” in neutron stars.

Short-range correlations in dynamical intranuclear cascade models for describing nucleon knockout reactions

Spallation and fragmentation reactions at incident energies above the Fermi momentum are considered to be the main mechanism for the production of neutron-rich nuclei at worldwide nuclear physics facilities, such as RIBF, FRIB, and GSI-FAIR. Although it is widely known that dynamical reaction models give a rather good prediction of cross sections for nuclear residues produced in spallation and fragmentation reactions, these reaction models fail in the description of peripheral collisions involving short-range nucleon-nucleon correlations (SRCs). Here, we present state-of-the-art dynamical reaction calculations based on the intranuclear cascade approach to describe spallation and fragmentation reactions. The new version of our dynamical model, including SRCs, successfully describes isotopic cross sections of neutron-rich nuclear residues and inclusive single-neutron and single-proton knockout cross sections for various stable and exotic nuclei. Finally, the results show that the systematic strong dependency of the single-knockout cross section reduction factor on the neutron-proton separation energy asymmetry parameter (ΔS) obtained by Tostevin and Gade disappears when SRCs are taken into account.

Measurement of the neutrino-oxygen neutral-current quasielastic cross section using atmospheric neutrinos in the SK-Gd experiment

We report the first measurement of the atmospheric neutrino-oxygen neutral-current quasielastic (NCQE) cross section in the gadolinium-loaded Super-Kamiokande (SK) water Cherenkov detector. In June 2020, SK began a new experimental phase, named SK-Gd, by loading 0.011% by mass of gadolinium into the ultrapure water of the SK detector. The introduction of gadolinium to ultrapure water has the effect of improving the neutron-tagging efficiency. Using a 552.2 day dataset from August 2020 to June 2022, we measure the NCQE cross section to be 0.74±0.22(stat)−0.15+0.85(syst)×10−38 cm2/oxygen in the energy range from 160 MeV to 10 GeV, which is consistent with the atmospheric neutrino-flux-averaged theoretical NCQE cross section and the measurement in the SK pure-water phase within the uncertainties. Furthermore, we compare the models of the nucleon-nucleus interactions in water and find that the binary cascade model and the Liège intranuclear cascade model provide a somewhat better fit to the observed data than the Bertini cascade model. Since the atmospheric neutrino-oxygen NCQE reactions are one of the main backgrounds in the search for diffuse supernova neutrino background (DSNB), these new results will contribute to future studies—and the potential discovery—of the DSNB in SK. Published by the American Physical Society 2024

The influence of Monte Carlo radiation transport codes and hadron physics models on stray neutron dose estimations in proton therapy: An extended intercomparison

PurposeSelecting a Monte Carlo (MC) radiation transport code and nuclear physics model affects the simulation of secondary neutron fluence energy spectra and the estimation of the neutron dose equivalent in proton therapy. This study compares the MC codes FLUKA, MCNPX and GEANT4 from previous work with two additional MC codes, TOPAS (with either the Binary Intra-nuclear Cascade (BIC) or the Bertini intra-nuclear cascade model (Bert)) and PHITS (with either the Intra-Nuclear Cascade of Liege (INCL) or the Bert model), to facilitate a more comprehensive comparison. Material and methodsSecondary neutron fluence energy spectra were scored at different locations inside a water phantom, exposed to a 10 × 10 cm2 parallel mono-energetic proton beam with energies of 110 MeV, 150 MeV, 180 MeV and 210 MeV. The neutron dose equivalent was estimated by applying fluence-to-dose equivalent conversion coefficients. ResultsDiscrepancies between MC codes and physics models reach 90 % for the total neutron fluence. Differences are most pronounced in the forward direction of the beam due to a notable presence of high-energy neutrons and the higher uncertainty on the neutron cross-section data for these neutrons. Nuclear model selection within PHITS (INCL or Bert) and TOPAS (BIC or Bert) shows a worse agreement for the Bert model than for the other MC codes and nuclear models. The discrepancies in the neutron spectrum simulations propagate into differences in the estimated neutron dose equivalents. They are more prominent for distal positions (up to a factor of 3) than for lateral positions (up to a factor of 2) and decrease at higher proton energies. ConclusionsThis study shows considerable differences in the out-of-field neutron fluence energy spectra calculated by different MC codes and nuclear physics models. Differences in the neutron dose equivalent reach a factor of 3. The discrepancies are most apparent in distal positions and at lower proton energies.

Effects of deuteron potentials on deuteron-induced nonelastic cross sections based on the intranuclear cascade model

Effects of deuteron potentials on deuteron-induced nonelastic cross sections based on the intranuclear cascade model

Secondary particle predictions in quasifree proton scattering reactions in the 100–250 MeV energy range

Results for observables related to the secondary particle production process in proton-nucleus spallation reactions at low beam incident energy (100--250 MeV) are shown. The energy and angular distributions of the residual nucleus are determined in the context of our multicollisional Monte Carlo intranuclear cascade model. The mechanism of proton-nucleus reactions is conventionally described as a sequence of two stages: the rapid intranuclear cascade phase and the slow particle evaporation step. In this work we focus on the rapid phase considering the nucleon effective mass as an effect of the many-body nuclear interactions and the intranuclear mean field. This procedure represents a more realistic scenario to obtain the particles' multiplicity generated in spallation reactions with light-mass target nuclei in a low-energy range. We focused our attention on target nuclei of macro elements, such as carbon, oxygen, phosphorus, sulfur, sodium, potassium, chlorine, and calcium, and trace elements such as iron, copper, zinc, bromine and selenium, which are the most frequent compounds of the organic material. The choice of these target nuclei is due to our expectancy that our results can work as a preliminary insight for further theoretical approaches, specially taking into account nuclear effects due to the interaction of the particles of the beam with the organic tissue.

Measurement of nuclide production cross sections for proton-induced reactions on [formula omitted]Ni and [formula omitted]Zr at 0.4, 1.3, 2.2, and 3.0 GeV

Nuclide production cross sections for proton-induced reactions on natNi and natZr at incident energies of 0.4, 1.3, 2.2, and 3.0 GeV were measured by the activation method at Japan Proton Accelerator Research Complex (J-PARC). In total, 24 and 43 residual nuclides were measured for the natNi and natZr targets, respectively. Among them, the cross sections of the following reactions were measured for the first time: natZr(p,x)28Mg, natZr(p,x)42K, natZr(p,x)43K, natZr(p,x)44gSc, natZr(p,x)55Co, natZr(p,x)69mZn, and natZr(p,x)93Y reactions. To examine the prediction capabilities, the measured data were compared with the spallation reaction models in PHITS (INCL4.6, Bertini, and JAM as intranuclear cascade models, and GEM as an evaporation model), INCL++/ABLA07, semi-empirical calculation code SPACS, and the JENDL/HE-2007 library. From the evaluation introducing the mean square deviation factor, the best reproducibility was exhibited by the JENDL/HE-2007 library for natNi and INCL++/ABLA07 for natZr.

Deuteron-induced nonelastic cross sections based on the intranuclear cascade model with independent incident particles under interaction potentials

Deuteron-induced nonelastic cross sections are studied in an extended intranuclear cascade (INC) model. A three-body framework of proton, neutron, and target is introduced into the INC model to incorporate naturally the decomposition and capture reactions from weakly bound deuterons. This framework includes three types of interaction potential, namely proton-target, neutron-target, and proton-neutron, the last of which causes the two nucleons in the deuteron to oscillate and play an important role in its breakup. The calculated results reproduce well the experimental data for $^{12}\mathrm{C}, ^{40}\mathrm{Ca}, ^{58}\mathrm{Ni}$, and $^{208}\mathrm{Pb}$ targets with almost the same parameters as those determined previously for nucleon-induced nonelastic reactions. It is found that the contribution of the two-nucleon collision process increases with target size, that the contribution of the capture processes is limited to a narrow region at low energy for lighter targets, and that the contribution of the breakup process is relatively small compared to other processes. It is also concluded that discrete-level-constraint effects dominate in the low-energy region for light nuclei such as $^{12}\mathrm{C}$, while Coulomb effects dominate in the low-energy region for heavy nuclei. This result is consistent with the INC model of nucleon incidence, which explains well the nucleon-induced nonelastic cross sections at low energies.

Benchmarking intranuclear cascade models for neutrino scattering with relativistic optical potentials

The description of final-state interactions (FSI) in the large phase space probed in neutrino experiments poses a great challenge. In neutrino experiments, which operate under semi-inclusive conditions, cascade models are commonly used for this task, while under exclusive conditions FSI can be treated with relativistic optical potentials (ROP). We formulate conditions under which the ROP approach and cascade model can be directly compared. We feed the NEUT cascade with events from a relativistic distorted-wave impulse approximation calculation that uses the real part of an optical potential. Cuts on the missing energy of the resulting events are applied to define a set of events that can be directly compared to RDWIA calculations with the full optical potential. The NEUT cascade and ROP agree for proton kinetic energies $T_p > 150$ MeV for carbon, oxygen and calcium nuclei when a realistic nuclear density is used to introduce events in the cascade. For $T_p < 100$ MeV the ROP and NEUT cross sections differ in shape and differences in magnitude are larger than 50 \%. Single transverse variables allow to distinguish different approaches to FSI, but due to a large non-QE contribution the comparison to T2K data does not give an unambiguous view of FSI. We discuss electron scattering and argue that with a cut in missing energy FSI can be studied with minimal confounding factors in e.g. $e4\nu$. The agreement of the ROP and NEUT for T2K conditions lends confidence to these models as a tool in oscillation analyses for sufficiently large nucleon kinetic energies. These results urge for caution when a cascade model is applied for small nucleon energies. The assessment of model assumptions relevant to this region are strongly encouraged. This paper provides novel constraints on cascade models from proton-nucleus scattering that can be easily applied to other neutrino event generators.

Study of neutrino-nucleus reactions with crisp model ( 0&lt;Eν&lt;3 GeV )

The neutrino-nucleus reactions are studied at energies from 0 to 3 GeV, using the CRISP program. To simulate these reactions, CRISP uses the Monte Carlo method through an intranuclear cascade model. Quase-elastic and baryonic resonance formation channels for the neutrino-nucleon interaction are considered. The total and differential particle emission cross-sections were obtained, obtaining a good agreement with the values reported by the MiniBooNE experiment. The influence of nuclear effects on the studied reactions, such as fermionic motion, the Pauli blocking mechanism, and the nucleonic separation energy, was shown. It was not possible to simultaneously reproduce the $\nu_\mu + D$ and $\nu_\mu + ^{12}C$ reactions using the same axial mass value. For the charged current quasi-elastic channel, $M_A = 0.95 \ GeV$ for the $\nu_\mu + D$ reaction, and $M_A = 1.35 \ GeV$ for the $\nu_\mu + ^{12}C$ reaction. This can be solved if one considers, in addition to the neutrino-nucleon interaction, the neutrino interaction with a pair of nucleons, just as we demonstrate in the last part of this work.

Hypernuclei formation in spallation reactions by coupling the Liège intranuclear cascade model to the deexcitation code ABLA

Innovative experiments using the inverse kinematics technique to accelerate light, medium-mass, and heavy nuclei at relativistic energies have become excellent tools to produce and study hypernuclei. We investigate hypernuclei created in spallation reactions, where multifragmentation, particle evaporation, and fission processes play an important role in the formation of final hypernuclei residues. For the description of spallation reactions, we couple the Li\`ege intranuclear cascade model, extended recently to the strange sector, to a new version of the ablation (ABLA) model that accounts for the evaporation of $\mathrm{\ensuremath{\Lambda}}$ particles from hot hyperremnants produced during the intranuclear cascade stage. These state of the art models are then used to study the production of hypernuclei close to drip lines through spallation-evaporation and fission reactions.

Measurement of nuclide production cross sections for proton-induced reactions on Mn and Co at 1.3, 2.2, and 3.0 GeV

Nuclide production cross sections for proton-induced reactions on Mn and Co at incident energies of 1.3, 2.2, and 3.0 GeV were measured by the activation method at the Japan Proton Accelerator Research Complex (J-PARC). In total, 143 production cross sections of reaction products with half-lives ranging from 1.8 h to 2.6 yr were obtained. Among them, the cross sections of 55Mn(p,x)38S, 55Mn(p,x)41Ar, and 59Co(p,x)38S reactions were measured for the first time. The stable proton beam and well-established beam profile-motoring system contributed to the reduction of the systematic uncertainties to typically less than 5%, which was better than those of the previous data (typically ∼10%). To examine the prediction capabilities of spallation reaction models and evaluated nuclear data library, the measured data were compared with the spallation reaction models in PHITS (INCL4.6, Bertini, and JAM as intranuclear cascade models, and GEM as an evaporation model), INCL++/ABLA07, and the JENDL/HE-2007 library. The comparison of the mean square deviation factors indicated that both INCL4.6/GEM and JENDL/HE-2007 showed better agreement with the measured data than the others.

Development of code IMPC-MC1.0 by implementing the function for proton transport simulation in OpenMC

For the target-reactor coupling calculation in Accelerator Driven Sub-critical System (ADS). We developed the proton-neutron transport code IMPC-MC1.0by embedding the Intra-Nuclear Cascade model of Liège (INCL++5.1) and abrasion-ABLAtion model (ABLA) fission-evaporation de-excitation model into the OpenMC (v0.12.0). To verify the code, the Brookhaven National Laboratory - Alternating Gradient Synchrotron (BNL-AGS) experimental benchmark was investigated. And the IMPC-MC1.0 results for neutron yield of the Pb and W target are in perfect agreement with those of measured values. Moreover, the simulated neutron leakage spectra are consistent with MCNPX and FLUKA calculations. Then the ADS target models filled with different materials were simulated, the results of neutron yield, energy spectrum are reasonable when compared with LAHET calculation. Finally, the homogenized Japan Atomic Energy Agency (JAEA) 800 MW lead-bismuth cooled target-reactor model was verified for ADS application. The related results are reliable when compared with the those calculated by MCNPX.

Assessment of secondary neutrons from galactic cosmic rays at mountain altitudes – Geant4 simulations and ground-based measurements of neutron energy spectra

In this study, the Geant4 Monte Carlo toolkit was used to simulate energy spectra of neutrons from secondary cosmic radiation at mountain altitudes for the Environmental Research Station “Schneefernerhaus” at the Zugspitze mountain, Germany (2660 m a.s.l.) and for Sphinx astronomical observatory at the Jungfraujoch, Switzerland (3585 m a.s.l.). Simulations were performed with different intra-nuclear cascade models available in Geant4, and the results were compared with those of measurements that had been performed at both locations by means of an Extended-Range Bonner Sphere Spectrometer. Measurement conditions were quite different for both locations – at Schneefernerhaus the measurements had been performed on the flank of a hill in March 2018 with much snow, while at Jungfraujoch the measurements had been performed on top of a steep local hill in September 2018 with much less snow. Despite these differences, agreement between measurement and simulation was reasonable at both locations, especially at neutron energies greater than 20 MeV where the (unknown) hydrogen content of the environment did not influence the neutron fluence much (i.e., results from simulations were 6–22% lower than those from the measurements for the Schneefernerhaus, and were 22–29% lower for Jungfraujoch, depending on intra-nuclear model used in the simulations). The agreement was less favorable for lower energies, where environmental hydrogen (e.g., snow cover, soil moisture) is known to influence the shape of the neutron energy spectrum, because the real conditions of the snow accumulation close to the location of the measurements were not known and, therefore, a detailed description of the real hydrogen environment in the simulations was not possible. When the results simulated using different intra-nuclear cascade models were compared with each other, agreement was found within ±5%, ±15%, ±20%, and ±20%, for cascade, evaporation, epithermal and thermal neutrons, respectively. While the latter results are consistent with those of simulations and measurements at the CERN EU High-Energy Reference Field (CERF) facility published recently, a detailed sensitivity analysis of the influence of environmental hydrogen on neutron energy spectra is required before a final quantitative comparison of measurements and simulations can be made. This sensitivity analysis is presently under way. It is concluded that simulation of energy spectra of neutrons from secondary cosmic rays close to the atmosphere-lithosphere interface, validated by the spectrometer measurements, showed differences of less than 30%, for neutron energies greater than 20 MeV, whatever intra-nuclear cascade model was used in the simulations.

Short-lived radionuclide production cross sections calculated by the Liège intranuclear cascade model

In this paper, we calculate the cross sections for proton-induced reactions producing short-lived radionuclides like $^{7,10}\mathrm{Be}$, $^{26}\mathrm{Al}$, $^{53,54}\mathrm{Mn}$, etc., with the Li\`ege intranuclear cascade model (incl$++$). The results show that the incl model, when coupled with the proper deexcitation model, gives satisfactory results for most of the considered reactions. Generally, results for reactions with $(\mathrm{\ensuremath{\Delta}}N\ensuremath{-}\mathrm{\ensuremath{\Delta}}Z)$ equal to 0 or 1 are more likely to precisely match experimental data than those for reactions with larger or smaller $|\mathrm{\ensuremath{\Delta}}N\ensuremath{-}\mathrm{\ensuremath{\Delta}}Z|$. Our results can provide useful references for both the users and developers of incl and deexcitation models.

New features of the INCL model for spallation reactions

The recent developments of the Liège intranuclear cascade model INCL are reviewed. The INCL4.6 version of this model was able when coupled with the ABLA07 de-excitation code, to describe rather well a huge set of experimental data in an incident energy range spanning between 200 MeV and 3 GeV, as it has been testified by an intercomparison of spallation codes organized by the IAEA. Since that time, the model has been implemented in several nuclear particle transport codes. Therefore, the possible applications of INCL have been enlarged to focus on diverse fields, and in the recent years, the model has been further developed to be applicable to these new issues and also to cope with remaining deficiencies. The new features include: i) a sophisticated dynamical model for light cluster emission (up to O ions), ii) the accommodation of light nuclei as projectiles, iii) a new procedure to take account of the fuzziness of the Fermi surface, and iv) an extension of the model to higher energy. The aim of this contribution is to present for the first time and to discuss the physics of the added features, and to give a hint about the performances of the new model.

Isobaric charge-exchange reactions: a tool to study the excitation of baryonic resonances in exotic nuclear matter

Isobaric charge-exchange reactions induced by beams of 112Sn have been investigated at the GSI facility using the fragment separator FRS. The high-resolving power of this spectrometer makes it possible to obtain the isobaric charge-exchange cross sections with an uncertainty of 3.5% and to separate quasi-elastic and inelastic contributions in the missing-energy spectra, in which the inelastic component is associated to the in-medium excitation of baryonic resonances such as the Δ resonance. We report on the results obtained for the (p,n) channel excited by using different targets that cover a large range in neutron excess. In addition, we also compare the missing-energy spectra with an intranuclear cascade model coupled to a de-excitation code to investigate the in-medium effects in the production of baryonic resonances.

Validation of nuclear reaction models for incident α-particles

Abstract Two different models allowing the calculation of reaction products are confronted with data from α-particle induced reactions. Both models contain a pre-equilibrium part and an equilibrium or compound nucleus part. The models are the exciton model in form of a code written by the author and TALYS. The other model is the intranuclear cascade model in form of the Liege-Saclay formulation incorporated in the PHITS code. The data are angle-integrated proton spectra from reactions with α-particle energies below 720 MeV and excitation functions from multi neutron emission with α-particle energies below 200 MeV.

Calculation and verification for energetic proton energy deposition in spallation target

Energy deposition in spallation target induced by energetic protons is the foundation and the premise of the spallation target research. In this paper, several intra-nuclear cascade models including BERTINI, ISABEL, CEM2K and INCL4 contained in MCNPX package, together with FLUKA and PHITS Monte Carlo codes are used to calculate the energy deposition in lead (Pb) and tungsten (W) spallation target impinged by 800, 1000, and 1200 MeV protons. The contributions of different particles to the total energy deposition in the Pb target are obtained and compared with each other as well. The energy deposition distribution caused by 250 MeV protons in the W target is measured with thermoluminescence detectors (TLDs). The results indicate that the calculations from the MCNPX accord with experimental data, verifying that the Monte Carlo code has a high reliability for energy deposition simulation.

Nuclide production cross sections from irradiation of thorium by 438 MeV protons and a comparison to fluka and geant4 simulations

Thorium targets were irradiated with 438-MeV protons, resulting in spallation and high-energy fission reactions. The measured production cross sections of 38 nuclides in the mass range 83 to 233 are reported. These cross-section data are useful for validating nuclear interaction models and are compared to simulated cross sections calculated using three different Monte Carlo packages, fluka (version 2011.2x.7), geant4 (version 10.6, with the Liege intranuclear cascade model and the abla version 3.1 evaporation code), and geant4 (version 10.6, with the binary cascade model). These data are also useful for estimating radionuclide production yields following an irradiation, in particular for the production of $^{225}\mathrm{Ac}$, a radionuclide of currently heightened interest in nuclear medicine for the treatment of cancer. For most nuclides reported, the measured, literature, and simulated cross-section values agree within a factor of 2.