Abrasion-ablation model for neutron production in heavy ion collisions

Francis, A Cucinotta; John, Walter; Lawrence, W Townsend

doi:10.1016/s0375-9474(97)00130-9

Cited by 20 publications

(11 citation statements)

References 17 publications

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“…The QMSFRG considers the multiple scattering series for two heavy ions and introduces the impulse and eikonal approximation for the total momentum transfer vector in order to obtain a closed-form solution to the abrasion cross section excitation spectrum [7][8][9][10]. For inclusive reactions where a single fragment originating in the projectile is measured, closure is performed on the final target state with a momentum vector denoted p used to represent these states.…”

Section: Quantum Fragmentation Modelmentioning

confidence: 99%

“…The de-excitation of the pre-fragments in nuclear ablation is described in a stochastic process using a Master equation for de-excitation by particle emission [9,10]. If f b (E,t) is the probability of finding the nuclei b at time t with excitation energy E b and P b,k (E) be the probability that the nuclei, b will emit ion k with energy E, then the Master equation is …”

Section: │T>mentioning

confidence: 99%

“…In evaluating fragmentation cross sections, equations (11) and (12) are solved by iteration up to excitation energies of 200 MeV [9,10], and using the approximation of Campi and Hufner [11] at higher values. The use of the statistical decay model with accurate nuclear level densities that include nuclear shell structure effects and the use of measured values for the nuclear masses are important for accurately predicting the odd-even effects in the fragment spectrum.…”

Section: │T>mentioning

confidence: 99%

“…To estimate nuclear coalescence contributions to d, t, h, and α production we consider the momentum distribution for proton (p) and neutron (n) production in the QMSFRG model [10,13], and apply the usual coalescence model [12], which consists of an A n -fold folding of the p and n-distribution to form a light ion of mass number A n . The n and p production cross sections are then reduced by the appropriate balancing of the cross sections resulting in light nuclei coalescence.…”

Section: │T>mentioning

confidence: 99%

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Description of light ion production cross sections and fluxes on the Mars surface using the QMSFRG model

Cucinotta

Kim

Schneider

et al. 2007

Radiat Environ Biophys

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The atmosphere of Mars significantly attenuates the heavy ion component of the primary galactic cosmic rays (GCR), however increases the fluence of secondary light ions (neutrons, and hydrogen and helium isotopes) because of particle production processes.We describe results of the quantum multiple scattering fragmentation (QMSFRG) model for the production of light nuclei through the distinct mechanisms of nuclear abrasion and ablation, coalescence, and cluster knockout. The QMSFRG model is shown to be in excellent agreement with available experimental data for nuclear fragmentation cross sections. We use the QMSFRG model and the space radiation transport code, HZETRN to make predictions of the light particle environment on the Martian surface at solar minimum and maximum. The radiation assessment detector (RAD) experiment will be launched in 2009 as part of the Mars Science Laboratory (MSL). We make predictions of the expected results for time dependent count-rates to be observed by RAD experiment.Finally, we consider sensitivity assessments of the impact of the Martian atmospheric composition on particle fluxes at the surface.https://ntrs.nasa.gov/search

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Section: Quantum Fragmentation Modelmentioning

confidence: 99%

Section: │T>mentioning

confidence: 99%

Section: │T>mentioning

confidence: 99%

Section: │T>mentioning

confidence: 99%

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Description of light ion production cross sections and fluxes on the Mars surface using the QMSFRG model

Cucinotta

Kim

Schneider

et al. 2007

Radiat Environ Biophys

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“…The prefragment then decays by particle emissions to more stable configuration. A recent version of an abrasion-ablation model [1] was formulated to include the momentum distribution for nucleon production in heavy-ion collisions. In its original form, the formulation included knockout contributions from both projectile and target nuclei, but contributions only from the projectile nucleus for the ablation stage.…”

Section: Introductionmentioning

confidence: 99%

Improved model for secondary neutron production in nucleus-nucleus collision at intermediate energies

Townsend

Sriprisan

Cucinotta

2007

Nd2007

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Abstract. In previous work an analytical knockout-ablation coalescence model capable of making quantitative predictions of the neutron spectra from high-energy nucleon-nucleus and nucleus-nucleus collision has been developed. The physics of the knockout-ablation model is similar to that in intranuclear cascade codes using Monte Carlo methods. In the first or knockout stage, the collision between two nuclei results in one or more nucleons being knocked out of the projectile and/or the target nucleus. This results in an excited nucleus (called a prefragment), which is lighter than the original species. This excited prefragment decays to the ground state by emitting one or more nucleons, composites (such as deuterons or alphas) and gammas. This is the ablation (second) stage of the reaction. Significant improvements in model predictions were made previously by incorporating important coalescence effects into the formalism. Coalescence occurs when particles with similar momenta located close together in space recombine to form heavier nuclei, such as deuterons, 3 H and 3 He. In this work the important effects of alpha particle coalescence are included. The improved theory is described and results for predicted neutron and light ion energy and angular spectra are presented and compared with published measurements of secondary neutron and light ion production for a variety of collision pairs.

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Comparison of Martian surface ionizing radiation measurements from MSL‐RAD with Badhwar‐O'Neill 2011/HZETRN model calculations

et al. 2014

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Dose rate measurements from Mars Science Laboratory-radiation assessment detector (MSL-RAD) for 300 sols on Mars are compared to simulation results using the Badhwar-O'Neill 2011 galactic cosmic ray (GCR) environment model and the high-charge and energy transport (HZETRN) code. For the nuclear interactions of primary GCR through Mars atmosphere and Curiosity rover, the quantum multiple scattering theory of nuclear fragmentation is used. Daily atmospheric pressure is measured at Gale Crater by the MSL Rover Environmental Monitoring Station. Particles impinging on top of the Martian atmosphere reach RAD after traversing varying depths of atmosphere that depend on the slant angles, and the model accounts for shielding of the RAD "E" detector (used for dosimetry) by the rest of the instrument. Simulation of average dose rate is in good agreement with RAD measurements for the first 200 sols and reproduces the observed variation of surface dose rate with changing heliospheric conditions and atmospheric pressure. Model results agree less well between sols 200 and 300 due to subtleties in the changing heliospheric conditions. It also suggests that the average contributions of albedo particles (charge number Z < 3) from Martian regolith comprise about 10% and 42% of the average daily point dose and dose equivalent, respectively. Neutron contributions to tissue-averaged effective doses will be reduced compared to point dose equivalent estimates because a large portion of the neutron point dose is due to low-energy neutrons with energies <1 MeV, which do not penetrate efficiently to deep-seated tissues. However the exposures from neutrons to humans on Mars should become an important consideration in radiobiology research and risk assessment.

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Abrasion-ablation model for neutron production in heavy ion collisions

Cited by 20 publications

References 17 publications

Description of light ion production cross sections and fluxes on the Mars surface using the QMSFRG model

Description of light ion production cross sections and fluxes on the Mars surface using the QMSFRG model

Improved model for secondary neutron production in nucleus-nucleus collision at intermediate energies

Comparison of Martian surface ionizing radiation measurements from MSL‐RAD with Badhwar‐O'Neill 2011/HZETRN model calculations

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