TEPC Measurements and Monte Carlo Calculations for Evaluating Ambient Dose Equivalent Response in Mixed Radiation Fields around the Shielded Area of a Carbon Ion Accelerator

2009 ◽  
Vol 168 (1) ◽  
pp. 118-122
Author(s):  
S. Rollet ◽  
P. Beck ◽  
M. Latocha ◽  
M. Wind ◽  
A. Zechner ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dose Equivalent ◽  
Carbon Ion ◽  
Monte Carlo Calculations ◽  
Radiation Fields ◽  
Ion Accelerator ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

EVALUATION OF NEUTRON AMBIENT DOSE EQUIVALENT IN CARBON-ION RADIOTHERAPY WITH ENERGY SCANNING

2020 ◽  
Vol 191 (3) ◽  
pp. 310-318
Author(s):  
Shinnosuke Matsumoto ◽  
Shunsuke Yonai
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Carbon Ion Radiotherapy ◽  
Neutron Energy Spectrum ◽  
Dose Equivalent ◽  
Realistic Case ◽  
Carbon Ion ◽  
Ambient Dose Equivalent ◽  
Secondary Neutrons ◽  
Ambient Dose

Abstract In carbon-ion radiotherapy (CIRT), secondary neutrons are produced by nuclear interactions in the beamline devices or patient. Herein, the characteristics of secondary neutrons in CIRT with energy scanning (ES) were evaluated. Neutron ambient dose equivalents (H*(10)) were measured using WENDI-II. The neutron energy spectrum was calculated using the Monte Carlo simulation. Measurement and calculation were performed under realistic case scenarios using maximum beam energies (Emax) of 290, 350 and 400 MeV u −1. Moreover, H*(10) in ES was compared with H*(10) in range-shifter scanning (RS) and hybrid scanning (HS). H*(10) in Emax = 290 MeV u−1 was 65% less than that in Emax = 400 MeV u−1. At Emax = 350 MeV u−1, H*(10) in ES at θ = 120 was 42% of that at θ = 60. The neutron dose in ES CIRT decreased to approximately 60 and 70% of that in RS and HS CIRT, respectively, at 50-cm distance from the beam axis.

scholarly journals Neutrons along the labyrinth of high energy medical accelerators: Effect of wall materials

2019 ◽  
Vol 21 ◽  
pp. 169
Author(s):  
M. Fakinou ◽  
I. E. Stamatelatos ◽  
J. Kalef-Ezra
Keyword(s):  
Monte Carlo ◽  
Cost Effective ◽  
High Energy ◽  
Wall Material ◽  
Mcnp Code ◽  
Dose Equivalent ◽  
Concrete Wall ◽  
Ambient Dose Equivalent ◽  
Wall Materials ◽  
Ambient Dose

Neutron streaming along the labyrinth of a generic bunker of an 18MV medical accelerator was evaluated. Monte Carlo simulations using MCNP code were performed to calculate neutron ambient dose equivalent along the labyrinth. The effect of plain, borated and barites concrete wall material, as well as borated concrete and plywood (Celotex), as neutron absorbing wall liners, was examined. The results of the study suggest that plywood can provide a cost effective material to attenuate neutron streaming along the labyrinth.

DEVELOPMENT OF A NEW SECONDARY STANDARD FOR H*(10)

2020 ◽  
Vol 188 (3) ◽  
pp. 378-382
Author(s):  
K Bairlein ◽  
B Behnke ◽  
O Hupe
Keyword(s):  
Ionization Chamber ◽  
Secondary Standard ◽  
Dose Equivalent ◽  
Air Kerma ◽  
Radiation Fields ◽  
Ambient Dose Equivalent ◽  
Conversion Coefficients ◽  
Aluminium Coating ◽  
Pulsed Fields ◽  
Ambient Dose

Abstract A secondary standard for ambient dose equivalent, H*(10), is necessary for the dissemination of the unit Sievert (Sv), but there is no such standard commercially available currently. Furthermore, the measurement of H*(10) instead of calculating H*(10) from air kerma and conversion coefficients is needed for unknown radiation fields. We developed a prototype of a new secondary standard for H*(10) based on a spherical 1 l ionization chamber for air kerma. This chamber was modified with copper wires at the inner surface to adjust the response of the chamber according to H*(10). Additionally, a Makrolon shell and an aluminium coating were added to optimize the response at energies below 50 keV. The prototype fulfils the requirements given in ISO 4037-2 in the energy range from 12 keV to 7 MeV. In combination with an electrometer, it can be used as area dosemeter, suitable for pulsed fields and for low energy radiation.

OPTIMIZATION OF AN ADDITIONAL COLLIMATOR IN A BEAM DELIVERY SYSTEM FOR REDUCTION OF THE SECONDARY NEUTRON EXPOSURE IN PASSIVE CARBON-ION THERAPY

2018 ◽  
Vol 184 (1) ◽  
pp. 28-35
Author(s):  
Masataka Komori ◽  
Akihiko Takeuchi ◽  
Maiko Niwa ◽  
Takaomi Harada ◽  
Hiroshi Oguchi
Keyword(s):  
Delivery System ◽  
Dose Equivalent ◽  
Carbon Ion Therapy ◽  
Carbon Ion ◽  
Ion Therapy ◽  
Ambient Dose Equivalent ◽  
Neutron Exposure ◽  
Beam Delivery ◽  
Beam Delivery System ◽  
Ambient Dose

Abstract The aim of this work is to optimize an additional collimator in a beam delivery system to reduce neutron exposure to patients in passive carbon-ion therapy. All studies were performed by Monte Carlo simulation assuming the beam delivery system at Heavy-Ion Medical Accelerator in Chiba. We calculated the neutron ambient dose equivalent at patient positions with an additional collimator, and optimized the position, aperture size and material of the collimator to reduce the neutron ambient dose equivalent. The collimator located 125 and 470 cm upstream from the isocenter could reduce the dose equivalent near the isocenter by 35%, while the collimator located 813 cm upstream from the isocenter was ineffective. As for the material of the collimator, iron and nickel could conduct reduction slightly better than aluminum and polymethyl methacrylate. The additional collimator is an effective method for the reduction of the neutron ambient dose equivalent near the isocenter.

scholarly journals Dose Rate Measurements in Pulsed Radiation Fields by Means of an Organic Scintillator

2021 ◽  
Vol 253 ◽  
pp. 09002
Author(s):  
Theresa Werner ◽  
Roland Beyer ◽  
Richard Biedermann ◽  
Marko Gerber ◽  
Jürgen Götze ◽  
...  
Keyword(s):  
Digital Data ◽  
Laser Machining ◽  
Dose Equivalent ◽  
Organic Scintillator ◽  
Radiation Fields ◽  
Medical Diagnostic ◽  
Ambient Dose Equivalent ◽  
Short Time ◽  
Ambient Dose

A deficiency in the implementation of current radiation protection is the determination of the ambient dose equivalent H*(10) and the directional dose equivalent H´(0.07) in pulsed radiation fields. Conventional dosimeter systems are not suitable for measurements in photon fields comprising short radiation pulses, which consequently leads to high detector loads in short time periods. Nevertheless, due to the implementation of advanced medical accelerators for cancer therapy, new medical diagnostic devices as well as various laser machining systems, there is an urgent need for suitable dosimeter systems for real time dosimetry. In this paper, a detector concept based on an organic scintillator and a full digital data analysis with the aim of developing a portable, battery powered measurement system is presented.

Decommissioning for the Containment Vessel of HTR-PM: Monte Carlo Simulation and Long-Time Predictions

2013 ◽  
Author(s):  
Wenqian Li ◽  
Hong Li ◽  
Jianzhu Cao ◽  
Ming Li ◽  
Feng Xie ◽  
...  
Keyword(s):  
Monte Carlo ◽  
National Standard ◽  
Dose Equivalent ◽  
Containment Vessel ◽  
Transport Code ◽  
Equivalent Rate ◽  
Activation Products ◽  
Long Time ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

A high temperature gas cooled reactor-pebble bed module (HTR-PM) is currently under design and construction in China. Calculations of induced radioactivity in the concrete containment vessel of HTR-PM were performed in order to predict the decommissioning problems. The main activation products and the ambient dose equivalent rate corresponding to 40 years of operations followed by 30 days/1 year/10 years of decay, were calculated by using the Monte Carlo particle transport code FLUKA. Finally, according to the Chinese National Standard and on the basis of the knowledge gained from this study, the classifications of the radioactive solid wastes were discussed, and some suggestions for the working duration of the employees were given.

scholarly journals Ambient dose equivalent measurements in secondary radiation fields at proton therapy facility CCB IFJ PAN in Krakow using recombination chambers

Nukleonika ◽  
2016 ◽  
Vol 61 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Edyta A. Jakubowska ◽  
Michał A. Gryziński ◽  
Natalia Golnik ◽  
Piotr Tulik ◽  
Liliana Stolarczyk ◽  
...  
Keyword(s):  
Nuclear Physics ◽  
Gamma Probe ◽  
Secondary Radiation ◽  
Dose Equivalent ◽  
Radiation Fields ◽  
Tissue Equivalent ◽  
Ambient Dose Equivalent ◽  
Dosimetric System ◽  
Ambient Dose

AbstractThis work presents recombination methods used for secondary radiation measurements at the Facility for Proton Radiotherapy of Eye Cancer at the Institute for Nuclear Physics, IFJ, in Krakow (Poland). The measurements ofH*(10) were performed, with REM-2 tissue equivalent chamber in two halls of cyclotrons AIC-144 and Proteus C-235 and in the corridors close to treatment rooms. The measurements were completed by determination of gamma radiation component, using a hydrogen-free recombination chamber. The results were compared with the measurements using rem meter types FHT 762 (WENDI-II) and NM2 FHT 192 gamma probe and with stationary dosimetric system.

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