scholarly journals Development of neutron survey meter using prescila neutron probe

2021 ◽  
Vol 8 (4) ◽  
pp. 26-33
Author(s):  
Hong Luong Thi ◽  
Phong Nguyen Tien ◽  
Bich Pham Thi ◽  
Huyen Nguyen Du
Keyword(s):  
High Energy ◽  
Energy Response ◽  
Dose Equivalent ◽  
Directional Response ◽  
Neutron Probe ◽  
Ambient Dose Equivalent ◽  
The Relationship ◽  
Non Destructive ◽  
Proper Operation ◽  
Ambient Dose

This paper presents the design and validation of a neutron survey meter. The meter consists of a PRESCILA neutron probe (with good sensitivity, directional response, gamma rejection, and enhanced high-energy response to 20 MeV) and an electrometer developed at Non-Destructive Evaluation center. The homogeneity response of the PRESCILA neutron probe was investigated as a function of distances from the 241Am - 9Be source in order to obtain the appropriate distance for accurate count-rate measurements using the neutron survey meter. A system consists of the PRESCILA neutron probe and the Ludlum Model 2326 electrometer was then used for measuring neutron ambient dose equivalent rates in the range from 50 cm to 200 cm with the step of 25 cm. The relationship between the count-rates and neutron dose equivalent rates (in the distance ranged from 50 to 200 cm) were deduced to validate the proper operation of the neutron survey meter.

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.

The Design of an Ambient Neutron Dose-Equivalent Meter

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Xia Wenming ◽  
Jia Mingchun ◽  
Guo Zhirong
Keyword(s):  
Neutron Radiation ◽  
Monte Carlo Code ◽  
Energy Response ◽  
Dose Equivalent ◽  
Neutron Dosimeter ◽  
Radiation Fields ◽  
Ambient Dose Equivalent ◽  
Ambient Dose ◽  
Detector Design ◽  
Single Counter

At present, most of the developed neutron dosimeters used to measure the neutron ambient dose-equivalent that has a moderator with a single counter, applied in neutron radiation fields within large range energies from thermal to MeV neutrons, are not a satisfaction to energy response. The purpose of this article is to design a suitable neutron dosimeter for radiation protection purpose. In order to overcome the disadvantage of the energy response of the neutron dosimeters combining a single sphere with a single counter, three spheres and three H3e counters were combined for the detector design. The response function of moderators with different thicknesses combined with SP9 H3e counters were calculated with Monte Carlo code MCNP 4C. The selection of three different thicknesses of the moderating polyethylene sphere was done with a MATLAB program. A suitable combination of three different thicknesses was confirmed for the detector design. The electronic system of the neutron dosimeter was introduced. The results of ambient dose-equivalent per unit fluence in different radiation areas were calculated, analyzed, and compared with the values recommended in the ISO standard. The calculated result explains that it is very significant to this design of neutron dosimeter; it may be applied to the monitor of the ambient dose in the neutron radiation fields, improving at present the status of the energy response of neutron dosimeters.

scholarly journals Potential benefit of retrospective use of neutron monitors in improving ionising radiation exposure assessment on international flights: issues raised by neutron passive dosimeter measurements and EPCARD simulations during sudden changes in solar activity

2020 ◽  
Vol 71 (2) ◽  
pp. 152-157
Author(s):  
Marina Poje Sovilj ◽  
Branko Vuković ◽  
Vanja Radolić ◽  
Igor Miklavčić ◽  
Denis Stanić
Keyword(s):  
Solar Activity ◽  
High Energy ◽  
Ionising Radiation ◽  
Neutron Dose ◽  
Flight Crew ◽  
Dose Equivalent ◽  
Ambient Dose Equivalent ◽  
Neutron Dose Equivalent ◽  
Neutron Component ◽  
Ambient Dose

AbstractSince air transport became more accessible, more and more people have been exposed to ionising radiation of cosmic origin. Measuring the neutron dose equivalent is a good approximation of total ambient dose equivalent, as neutrons carry about 50 % of the dose at flight altitudes. The aim of our study was to compare our measurements of the neutron component of secondary cosmic radiation dose, taken with passive dosimeters, with the data obtained from a simulation generated by EPCARD software, which is common in assessing flight crew exposure to ionising radiation. We observed deviations (both above and below) from the expected proportion of the neutron component (between 40 and 80 %), which pointed to certain issues with actual passive dosimeter measurement and the EPCARD simulation. The main limitation of the dosimeter are large uncertainties in high energy neutron response, which may result in underestimation of neutron dose equivalent. The main drawback of the software simulation is monthly averaging of solar potential in calculations, which can neglect sporadic high energy events. Since airlines worldwide almost exclusively use software (due to costs and convenience) to estimate the dose received by their crew, it is advisable to retrospectively recalculate the dose taking into account neutron monitor readings when solar activity changes.

Calculations of Effective Dose and Ambient Dose Equivalent Conversion Coefficients for High Energy Photons

1999 ◽  
Vol 36 (11) ◽  
pp. 977-987 ◽  
Author(s):  
Osamu SATO ◽  
Nobuaki YOSHIZAWA ◽  
Shunji TAKAGI ◽  
Satoshi IWAI ◽  
Takashi UEHARA ◽  
...  
Keyword(s):  
Effective Dose ◽  
High Energy ◽  
Dose Equivalent ◽  
Ambient Dose Equivalent ◽  
Conversion Coefficients ◽  
Ambient Dose
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