Validation of Geant4 physics models for nuclear beams in extended media

Chen, Junliang; Yun, Seong Dae; Dong, Ting; Ren, Zhongzhou; Zhang, Xiaoping

doi:10.1016/j.nimb.2018.08.022

Cited by 4 publications

(3 citation statements)

References 37 publications

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“…These particles are pure secondary particles generated in reactions between primary GCRs and atmospheric molecules, and the observed discrepancy might be owing to the lower generation cross sections. Based on the previous work, the cross sections for light fragments simulated by the G4QMD model were lower than the experimental data [35].…”

Section: Resultsmentioning

confidence: 75%

“…The binary cascade model (BIC) was used for dealing with nucleon-nucleus interactions at intermediate energies, and high-precision neutron models (HPs) were used for dealing with neutron-nucleus interactions involving energies below 20 MeV. For the inelastic interactions of nuclei, the G4QMD model that was validated in our previous work was used [35]. In this model, all nucleons were considered as participant particles, and each nucleon was treated as a Gaussian wave packet.…”

Section: Model Setupmentioning

confidence: 99%

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Studies of the radiation environment on the Mars surface using the Geant4 toolkit

et al. 2022

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The radiation environment on the surface of Mars is a potential threat for future manned exploration missions to this planet. In this study, a simple geometrical model was built for simulating the radiation environment on the Mars surface caused by galactic cosmic rays; the model was built and studied using the Geant4 toolkit. The simulation results were compared with the data reported by a radiation assessment detector (RAD). The simulated spectra of neutrons, photons, protons, $$\alpha$$ α particles, and particle groups $$Z=3$$ Z = 3 –5, $$Z=6$$ Z = 6 –8, $$Z=9$$ Z = 9 –13, and $$Z=14$$ Z = 14 –24 were in a reasonable agreement with the RAD data. However, for deuterons, tritons, and $$\,^{3}{\mathrm{He}}$$ 3 He , the simulations yielded much smaller values than for the corresponding RAD data. In addition, the particles’ spectra within the $$90^{\circ }$$ 90 ∘ zenith angle were also obtained. Based on these spectra, we calculated the radiation dose that would have been received by an average human body on Mars. The distribution of the dose throughout the human body was not uniform. The absorbed and equivalent doses for the brain were the highest among all of the organs, reaching 62.0 ± 1.7 mGy/y and 234.1 ± 8.0 mSv/y, respectively. The average absorbed and equivalent doses for the entire body were approximately 44 mGy/y and 153 mSv/y, respectively. Further analysis revealed that most of the radiation dose was owing to $$\alpha$$ α particles, protons, and heavy ions. We then studied the shielding effect of the Mars soil with respect to the radiation. The body dose decreased significantly with increasing soil depth. At the depth of 1.5 m, the effective dose for the entire body was 17.9 ± 2.4 mSv/y, lower than the dose limit for occupational exposure. At the depth of 3 m, the effective dose to the body was 2.7 ± 1.0 mSv/y, still higher than the accepted dose limit.

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Section: Resultsmentioning

confidence: 75%

Section: Model Setupmentioning

confidence: 99%

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

et al. 2022

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“…However, our data of the CR spectrum on the lunar surface are limited and those derived from CR particle flux models are generally taken as an approximate substitution. Therefore, the CR spectrum on the lunar surface can provide these CR-related studies with actual measurements and tools to refine related models (39)(40)(41)(42)(43). Moreover, the differential flux ratio of 3 He to 4 He, which is a powerful tool to constrain the CR propagation models, was measured in various experiments as reported by Wu and Chen (44) and the literature therein.…”

Section: Introductionmentioning

confidence: 99%

First measurements of low-energy cosmic rays on the surface of the lunar farside from Chang’E-4 mission

Luo

Zhang

et al. 2022

Sci. Adv.

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Development of a more accurate Geant4 quantum molecular dynamics model for hadron therapy

Sato¹,

Sakata²,

Bolst³

et al. 2022

Phys. Med. Biol.

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Objective: Although in heavy-ion therapy, the quantum molecular dynamics (QMD) model is one of the most fundamental physics models providing an accurate daughter-ion production yield in the final state, there are still non-negligible differences with the experimental results. The aim of this study is to improve fragment production in water phantoms by developing a more accurate QMD model in Geant4. Approach: A QMD model was developed by implementing modern Skyrme interaction parameter sets, as well as by incorporating with an ad hoc α-cluster model in the initial nuclear state. Two adjusting parameters were selected that can significantly affect the fragment productions in the QMD model: the radius to discriminate a cluster to which nucleons belong after the nucleus-nucleus reaction, denoted by R, and the squared standard deviation of the Gaussian packet, denoted by L. Squared Mahalanobis's distance of fragment yields and angular distributions with 1, 2, and the higher atomic number for the produced fragments were employed as objective functions, and multi-objective optimization (MOO), which make it possible to compare quantitatively the simulated production yields with the reference experimental data, was performed. Main results: The MOO analysis showed that the QMD model with modern Skyrme parameters coupled with the proposed α-cluster model, denoted as SkM*α, can drastically improve light fragments yields in water. In addition, the proposed model reproduced the kinetic energy distribution of the fragments accurately. The optimized L in SkM*α was confirmed to be realistic by the charge radii analysis in the ground state formation. Significance: The proposed framework using MOO was demonstrated to be very useful in judging the superiority of the proposed nuclear model. The optimized QMD model is expected to improve the accuracy of heavy-ion therapy dosimetry.

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Validation of Geant4 physics models for nuclear beams in extended media

Cited by 4 publications

References 37 publications

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

Studies of the radiation environment on the Mars surface using the Geant4 toolkit

First measurements of low-energy cosmic rays on the surface of the lunar farside from Chang’E-4 mission

Development of a more accurate Geant4 quantum molecular dynamics model for hadron therapy

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