Simulated workplace neutron fields

Lacoste,; Taylor, G C; Röttger, Stefan

doi:10.1088/0026-1394/48/6/s07

Cited by 7 publications

(5 citation statements)

References 30 publications

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“…This implies the use of several monoenergetic or quasimonoenergetic neutron fields. Such fields are available from a few keV up to several hundred MeV [17,18], as well as thermal neutron fields giving the low energy point [19]. Information on the response in the intermediate energy range can be extracted from calibration in realistic neutron fields [18,20].…”

Section: Methods Of Response Function Determinationmentioning

confidence: 99%

“…Such fields are available from a few keV up to several hundred MeV [17,18], as well as thermal neutron fields giving the low energy point [19]. Information on the response in the intermediate energy range can be extracted from calibration in realistic neutron fields [18,20]. The use of S316 Metrologia, 48 (2011) S313-S327 bare radionuclide neutron sources [21] should be restricted to complementary information or response stability checks.…”

Section: Methods Of Response Function Determinationmentioning

confidence: 99%

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Calibration of neutron-sensitive devices

Gressier¹,

Taylor²

2011

Metrologia

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The calibration of a neutron-sensitive device can range from a simple calibration factor at a single energy or energy distribution to a full response characterization over the entire energy range to which the device is sensitive. As the responses of neutron-sensitive devices and the fluence-to-dose-equivalent conversion coefficients can vary with neutron energy and incident angle, both simulation and experiments in standard neutron fields are required. Although several ISO standards present calibration principles in general and detailed discussion on many specific areas, there are certain omissions and limitations that this paper intends to highlight, along with some new recommendations derived from the recent literature, mainly focused on the effective centre, corrections for geometry and neutron scattering, as well as the problem of calibrating in terms of personal dose equivalent.

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Section: Methods Of Response Function Determinationmentioning

confidence: 99%

Section: Methods Of Response Function Determinationmentioning

confidence: 99%

Calibration of neutron-sensitive devices

Gressier¹,

Taylor²

2011

Metrologia

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“…To this end the simulated workplace fields were introduced by ISO in 2008 (ISO 2008), whose use is recommended for calibration of neutron dosimeters. Some few facilities are already equipped with specific installations for calibration purposes simulating more realistic workplace fields, such as IRSN/CANEL, NPL, PTB and CERF (Lacoste 2010, Lacoste et al 2011. Another solution sometimes employed in practice is to directly calibrate at the workplace or to determine an additional correction factor k, specific from the workplace field to take into account the differences between this and the calibration field, and those between the curve of conversion coefficients and the detector response (Mayer et al 2007, Bedogni et al 2013, Luszik-Bhadra 2016.…”

Section: R E R E H E mentioning

confidence: 99%

Study of the responses and calibration procedures of neutron and gamma area and environmental detectors for use in proton therapy

et al. 2019

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Ambient dose equivalent measurements with radiation protection instruments are associated to large uncertainties, mostly due to the energy dependence of the instrument response and to the dissimilarity between the spectra of the standard calibration source and the workplace field. The purpose of this work is to evaluate its impact on the performance of area and environmental detectors in the proton therapy environment, and to provide practical solutions whenever needed and possible. The study was carried out at the Centre Antoine Lacassagne (CAL) proton therapy site, and included a number of commercially available area detectors and a home-made environmental thermoluminescent dosimeter based on a polyethylene moderator loaded with TLD600H/TLD700H pairs. Monte Carlo simulations were performed with MCNP to calculate, first, missing or partially lacking instrument responses, covering the range of energies involved in proton therapy. Second, neutron and gamma spectra were computed at selected positions in and outside the CAL proton therapy bunkers. Appropriate correction factors were then derived for each detector, workplace location and calibration radionuclide source, which amounts to up to 1.9 and 1.5 for neutron and photon area detectors, respectively, and suggest that common ambient dose equivalent instruments might not meet IEC requirements. The TLD environmental system was calibrated in situ and appropriate correction factors were applied to account for the cosmic spectra. Measurements performed with this system from 2014 to 2017 around the installation were consistent with reference natural background dose data and with pre-operational levels registered at the site before the construction of the building in 1988, showing thus no contribution from the site clinical activities. An in situ verification procedure for the radiation protection instruments was also implemented in 2016 at the low energy treatment room using the QA beam reference conditions. The method presents main methodological, practical and economic advantages over external verifications.

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“…There are at the present time no standards for high-energy neutron fields (above 20 MeV). As described in this issue [20,33], they can be considered either as a parallel quasimonoenergetic neutron beam or a simulated workplace neutron field, e.g. the CERN-EU High Energy Reference Field Facility (CERF).…”

Section: International Standardsmentioning

confidence: 99%

What is neutron metrology and why is it needed?

Thomas¹,

Nolte²,

Gressier³

2011

Metrologia

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In some branches of metrology the quantity, or quantities, to be measured and the requirements for standards of this quantity, or these quantities, are clear-cut, although the accuracies required may not always be obvious. Good examples are time, length and mass. The quantities measured in neutron metrology and the requirements and uses of these quantities are less well known. This paper lays the foundation for subsequent more detailed discussions of the problems and issues faced by national metrology institutes when developing and providing standards.

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Simulated workplace neutron fields

Cited by 7 publications

References 30 publications

Calibration of neutron-sensitive devices

Calibration of neutron-sensitive devices

Study of the responses and calibration procedures of neutron and gamma area and environmental detectors for use in proton therapy

What is neutron metrology and why is it needed?

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