Monte Carlo Study in Radiation Damage Experiments of Permanent Magnets by High Energy Electrons

Author(s):  
Rui Qiu ◽  
Hee-Seock Lee ◽  
Tae-Yeong Koo ◽  
Junli Li
1972 ◽  
Vol 11 (2) ◽  
pp. K103-K104 ◽  
Author(s):  
F. Fujimoto ◽  
H. Fujita

2007 ◽  
Vol 16 (10) ◽  
pp. 3355-3362
Author(s):  
DU JIAXIN ◽  
LI NA ◽  
LIU LIANSHOU

A Monte Carlo study on the charge balance function in high energy hadron-hadron and relativistic heavy ion collisions are carried out using the Monte Carlo generators PYTHIA and AMPT, respectively. A strong dependence of the width of balance function on multiplicity is found in both cases. Using the mean parton-freeze-out time of a heavy-ion-collision event as the characteristic hadronization time for the event, it is found that for a fixed multiplicity interval the width of balance function is consistent with being independent of hadronization time.


2018 ◽  
Vol 8 (3Sep) ◽  
Author(s):  
A S Talebi ◽  
M Maleki ◽  
P Hejazi ◽  
M Jadidi ◽  
R Ghorbani

BackgroundOne of the most significant Intensity Modulated Radiation Therapy treatment benefits is a high target to normal tissue dose ratio. To improve this advantage, an additional accessory such as a compensator is used to delivering doses. Compensator-based IMRT treatment is usually operated with an energy higher than 10 MV. Photoneutrons, which have high linear energy transfer and radiobiological effectiveness, are produced by colliding high-energy photon beams with linear accelerator structures, then they deliver the unwanted doses to patients and staff. Therefore, the neutron energy spectra should be determined in order to calculate and reduce the photoneutron risk.Objective: We have conducted a comprehensive and precise study on the influence of brass compensator thickness and field size on neutron contamination spectrum in an Elekta SL 75/25 medical linear accelerator with and without the flattening filter by Monte Carlo method.Materials and Methods: MCNPX MC Code version 2.6.0 was utilized to simulate the detailed geometry of Elekta SL 75/25 head components based on Linac’s manual. This code includes an important feature to simulate the photo-neutron interactions. Photoneutrons spectrum was calculated after the Linac output benchmarking based on tuning the primary electron beam.Results and Conclusion: Based on the Friedman and Wilcoxon nonparametric tests results (P<0.05), photoneutron fluence directly depends on the field size and compensator thickness. Moreover, the unflattened beam provides lower photoneutron fluence than the flattened beam. Photoneutrons fluence is not negligible in compensator-based IMRT treatment. However, in order to optimize treatment plans, this additional and unwanted dose must be accounted for patients.


Author(s):  
Arezoo Kazemzadeh ◽  
Habiballah Moradi

Purpose: Recently, the application of high atomic number nanoparticles is suggested in the field of radiotherapy to improve physical dose enhancement and hence treatment efficiency. Several factors such as concentration and material of nanoparticles and energy of beam define the amount of dose enhancement in the target in the presence of nanoparticles. Materials and Methods: In this approach, a spherical cell was simulated through the Geant4 Monte Carlo toolkit which contained a nucleus and nanoparticles distributed through the cell. To investigate the effect of the concentration of nanoparticles on the deposited dose, it ranged from 3 mg/g to 30 mg/g for different materials like gold, silver, gadolinium, and platinum. Also, various mono-energetic photon beams included low and high energy sources were applied. Results: The results proved that as the concentration increased, the Dose Enhancement Factor (DEF) enlarged. Overall, almost for all energy and material that were used in this study, the maximum of DEF values occurred in the concentration of 30 mg/g. Moreover, lower energy sources presented higher DEF compared to other sources. The results indicated that the highest amount of DEF transpired for 35 keV photon beams equal to 14.67. Also, the K-edge energy of each material affects DEF values. Conclusion: To obtain a better outcome in the use of nanoparticles in combination with radiotherapy, a higher concentration of nanoparticles and low-energy photons should be considered to optimize the DEF and thus the treatment ratio.


2021 ◽  
pp. 17-21
Author(s):  
V.V. Gann ◽  
A.V. Gann ◽  
B.V. Borts ◽  
I.M. Karnaukhov ◽  
P.I. Gladkikh ◽  
...  

In this work, mathematical modeling of a complex of processes occurring in a tungsten target under irradiation with high-energy electrons with an energy of 100 MeV: an electromagnetic shower, the production of photo-neutrons, and particle transport along the target, damage from neutrons of the subcritical assembly. It was found that the greatest contribution to the rate of damage formation in a tungsten target give the elastic scattering of high-energy electrons on nuclei.


Sign in / Sign up

Export Citation Format

Share Document