scholarly journals CALCULATION OF SECONDARY NEUTRON FIELDS GENERATED BY HIGH-ENERGY HEAVY-ION REACTIONS USING MONTE-CARLO CODE PHITS

2007 ◽  
Author(s):  
Hiroshi Iwase ◽  
D. Schardt ◽  
K. Gunzert-Marx ◽  
E. Haettner ◽  
K. Niita
Keyword(s):  
Monte Carlo ◽  
Heavy Ion ◽  
High Energy ◽  
Monte Carlo Code ◽  
Secondary Neutron ◽  
Heavy Ion Reactions

Assessment of secondary neutrons in particle therapy by Monte Carlo simulations

2021 ◽  
Author(s):  
José Vedelago ◽  
Federico A Geser ◽  
Iván D Muñoz ◽  
Alberto Stabilini ◽  
Eduardo G Yukihara ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Angular Distribution ◽  
Monte Carlo Simulations ◽  
Radiation Transport ◽  
Heavy Ion ◽  
High Energy ◽  
Particle Therapy ◽  
Carbon Ions ◽  
Secondary Neutron ◽  
Secondary Neutrons

Abstract Objective: The purpose of this study is to estimate the energy and angular distribution of secondary neutrons inside a phantom in hadron therapy, which will support decisions on detector choice and experimental setup design for in-phantom secondary neutron measurements. Approach: Dedicated Monte Carlo simulations were implemented, considering clinically relevant energies of protons, helium and carbon ions. Since scored quantities can vary from different radiation transport models, the codes FLUKA, TOPAS and MCNP were used. The geometry of an active scanning beam delivery system for heavy ion treatment was implemented, and simulations of pristine and spread-out Bragg peaks were carried out. Previous studies, focused on specific ion types or single energies, are qualitatively in agreement with the obtained results. Main results: The secondary neutrons energy distributions present a continuous spectrum with two peaks, one centred on the thermal/epithermal region, and one on the high-energy region, with the most probable energy ranging from 19 MeV up to 240 MeV, depending on the ion type and its initial energy. The simulations show that the secondary neutron energies may exceed 400 MeV and, therefore, suitable neutron detectors for this energy range shall be needed. Additionally, the angular distribution of the low energy neutrons is quite isotropic, whereas the fast/relativistic neutrons are mainly scattered in the down-stream direction. Significance: It would be possible to minimize the influence of the heavy ions when measuring the neutron-generated recoil protons by selecting appropriate measurement positions within the phantom. Although there are discrepancies among the three Monte Carlo codes, the results agree qualitatively and in order of magnitude, being sufficient to support further investigations with the ultimate goal of mapping the secondary neutron doses both in- and out-of-field in hadrontherapy. The obtained secondary neutron spectra are available as supplementary material.

The Hydrodynamic Model for High-Energy Heavy Ion Reactions

1994 ◽  
pp. 11-22
Author(s):  
Y. Pürsün ◽  
U. Katscher ◽  
A. von Keitz ◽  
D. H. Rischke ◽  
B. Waldhauser ◽  
...  
Keyword(s):  
Hydrodynamic Model ◽  
Heavy Ion ◽  
High Energy ◽  
Heavy Ion Reactions

Development of Heavy Ion Transport Monte Carlo Code

2001 ◽  
pp. 973-978
Author(s):  
H. Iwase ◽  
T. Kurosawa ◽  
T. Nakamura ◽  
N. Yoshizawa ◽  
J. Funabiki
Keyword(s):  
Monte Carlo ◽  
Ion Transport ◽  
Heavy Ion ◽  
Monte Carlo Code

ASSESSMENT OF AMBIENT NEUTRON DOSE EQUIVALENT IN SPATIALLY FRACTIONATED RADIOTHERAPY WITH PROTONS USING PHYSICAL COLLIMATORS

2020 ◽  
Vol 189 (2) ◽  
pp. 190-197 ◽  
Author(s):  
Serdar Charyyev ◽  
C-K Chris Wang
Keyword(s):  
Monte Carlo ◽  
Neutron Dose ◽  
Monte Carlo Code ◽  
Dose Equivalent ◽  
Secondary Neutron ◽  
Fractionated Radiotherapy ◽  
Spot Scanning ◽  
Neutron Dose Equivalent ◽  
Secondary Neutrons ◽  
Proton Dose

Abstract New technique is trending in spatially fractionated radiotherapy with protons to utilize the spot scanning together with a physical collimator to obtain minibeams. The primary goal of this study is to quantify ambient neutron dose equivalent (${H}^{\ast }(10)$) due to the secondary neutrons when physical collimator is used to achieve desired minibeams. The ${H}^{\ast }(10)$ per treatment proton dose (D) was assessed using Monte Carlo code TOPAS and measured using WENDI-II detector at different angles (135, 180, 225 and 270 degrees) and distances (11 cm, 58 and 105 cm) from the phantom for two cases: with and without physical collimation. Without collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.0013 to 0.242 mSv/Gy. With collimation $\frac{H^{\ast }(10)}{D}$ varied from 0.017 to 3.23 mSv/Gy. Results show that the secondary neutron dose will increase tenfold when the physical collimator is used. Regardless, it will be low and comparable to the neutron dose produced by conventional passive-scattered proton beams.

scholarly journals Composition Classification of Ultra-High Energy Cosmic Rays

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 998
Author(s):  
Luis Javier Herrera ◽  
Carlos José Todero Peixoto ◽  
Oresti Baños ◽  
Juan Miguel Carceller ◽  
Francisco Carrillo ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Cosmic Rays ◽  
Computational Cost ◽  
Simulated Data ◽  
Ground Level ◽  
High Energy ◽  
Monte Carlo Code ◽  
High Energy Cosmic Rays ◽  
Research Fields ◽  
The Many

The study of cosmic rays remains as one of the most challenging research fields in Physics. From the many questions still open in this area, knowledge of the type of primary for each event remains as one of the most important issues. All of the cosmic rays observatories have been trying to solve this question for at least six decades, but have not yet succeeded. The main obstacle is the impossibility of directly detecting high energy primary events, being necessary to use Monte Carlo models and simulations to characterize generated particles cascades. This work presents the results attained using a simulated dataset that was provided by the Monte Carlo code CORSIKA, which is a simulator of high energy particles interactions with the atmosphere, resulting in a cascade of secondary particles extending for a few kilometers (in diameter) at ground level. Using this simulated data, a set of machine learning classifiers have been designed and trained, and their computational cost and effectiveness compared, when classifying the type of primary under ideal measuring conditions. Additionally, a feature selection algorithm has allowed for identifying the relevance of the considered features. The results confirm the importance of the electromagnetic-muonic component separation from signal data measured for the problem. The obtained results are quite encouraging and open new work lines for future more restrictive simulations.

Comparison between calculation and measured data on secondary neutron energy spectra by heavy ion reactions from different thick targets

2005 ◽  
Vol 116 (1-4) ◽  
pp. 640-646 ◽  
Author(s):  
H. Iwase ◽  
B. Wiegel ◽  
G. Fehrenbacher ◽  
D. Schardt ◽  
T. Nakamura ◽  
...  
Keyword(s):  
Neutron Energy ◽  
Heavy Ion ◽  
Measured Data ◽  
Energy Spectra ◽  
Secondary Neutron ◽  
Heavy Ion Reactions

ON THE RELATION BETWEEN THE WIDTH OF CHARGE BALANCE FUNCTION AND HADRONIZATION TIME IN RELATIVISTIC HEAVY ION COLLISION

2007 ◽  
Vol 16 (10) ◽  
pp. 3355-3362
Author(s):  
DU JIAXIN ◽  
LI NA ◽  
LIU LIANSHOU
Keyword(s):  
Monte Carlo ◽  
Strong Dependence ◽  
Monte Carlo Study ◽  
Heavy Ion ◽  
High Energy ◽  
Relativistic Heavy Ion Collisions ◽  
Heavy Ion Collision ◽  
Balance Function ◽  
Charge Balance ◽  
Ion Collision

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.

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