Study of neutron scattering contribution on Hp(10) and H*(10) calibration in the Brazilian National Low Scattering Laboratory

Freitas, Bruno Mendes; Pereira, Walsan Wagner; Patrão, K C S; Fonseca, Evaldo Simões da; Maurício, C.L.P.

doi:10.1093/rpd/ncu195

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…The source used in the NIS neutron facility is a 0.185 GBq Am-Be produced by Amersham [12]. The shield of this installation is composed of 45% hydrogenous material (asphalt), 5% borax and 50% sand which is collected in a wooden box of dimension 120 Â 120 Â 140 cm 3 where the background is smaller than 1 mSv/h on the surface of the boxwood. The box is in the irradiation room dimension of 4 m width, 4 m height, and 10 m length in the basement.…”

Section: Experimental and Methodologymentioning

confidence: 99%

“…Thus, it is imperative that the parameters affecting the traceability and uncertainties in its own irradiation facility have to be characterized thoroughly by reviewing irradiation setup and calibration procedures. The irradiation facility setup, the environmental conditions and the dosimetry system are the most substantial and important elements [1][2][3][4][5]. One of such activities is the calibration of neutron survey meters and neutron dosimeters.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of NIS neutron irradiation facility for calibration and metrological application

El-Sersy

Sayed

Nagib

et al. 2021

Int. J. Metrol. Qual. Eng.

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In this study, the Neutron Irradiation Facility (NIF) of the National Institute of Standards (NIS) was characterized for metrological applications to improve the accuracy of the calibration process. The NIS neutron irradiation facility consists of a 5 Ci Am-Be and 0.1 μg Cf-252 sources. The flux and dose rate of the Am-Be source was calculated by using MCNP5 code simulation at different distances from the source. The dose rate delivered by the source was determined using NM2-neutron monitor at different source-to-detector distances. A comparison between the measured and the calculated dose rate was performed and the deviation between them was explained in the skeletal arrangement of room scattering contribution. A shadow cone was designed and constructed to determine the scattering contribution at different source-to-detector distances. The optimum source-distance used for calibration was specified. It was found that the Am-Be calculated flux vary with distances from about 107–104 (n/cm2.S−1). The measured and the calculated dose rates were in agreement up to 150 cm distance from the source center after which the measured dose was greater than that calculated. The determined neutron scattering calculated from the measured-to-calculate dose ratio increased from 7% to 25% with increased distances from 150 to 300 cm. Moreover, the standard dose used in the calibration should be measured by a standard neutron monitor at each distance due to the higher value of the room scattering contribution where the optimum distance for calibration was 150 cm. The combined uncertainty of the measured neutron dose was 4.04%.

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Section: Experimental and Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of NIS neutron irradiation facility for calibration and metrological application

El-Sersy

Sayed

Nagib

et al. 2021

Int. J. Metrol. Qual. Eng.

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Use of Monte Carlo simulation and the Shadow-Cone Method to evaluate the neutron scattering correction at a calibration laboratory

Alvarenga

Polo

Pereira

et al. 2020

Radiation Physics and Chemistry

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ESTIMATION OF NEUTRON SCATTER CORRECTION FOR CALIBRATION OF PERSONNEL DOSIMETER AND DOSERATEMETER AGAINST 241Am–Be SOURCE—MONTE CARLO SIMULATION AND MEASUREMENTS

Dawn

Bakshi

Sathian

et al. 2016

Radiat Prot Dosimetry

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Neutron scatter contributions as a function of distance along the transverse axis of 241Am-Be source were estimated by three different methods such as shadow cone, semi-empirical and Monte Carlo. The Monte Carlo-based FLUKA code was used to simulate the existing room used for the calibration of CR-39 detector as well as LB6411 doseratemeter for selected distances from 241Am-Be source. The modified 241Am-Be spectra at different irradiation geometries such as at different source detector distances, behind the shadow cone, at the surface of the water phantom were also evaluated using Monte Carlo calculations. Neutron scatter contributions, estimated using three different methods compare reasonably well. It is proposed to use the scattering correction factors estimated through Monte Carlo simulation and other methods for the calibration of CR-39 detector and doseratemeter at 0.75 and 1 m distance from the source.

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Study of neutron scattering contribution on Hp(10) and H*(10) calibration in the Brazilian National Low Scattering Laboratory

Cited by 3 publications

References 4 publications

Characterization of NIS neutron irradiation facility for calibration and metrological application

Characterization of NIS neutron irradiation facility for calibration and metrological application

Use of Monte Carlo simulation and the Shadow-Cone Method to evaluate the neutron scattering correction at a calibration laboratory

ESTIMATION OF NEUTRON SCATTER CORRECTION FOR CALIBRATION OF PERSONNEL DOSIMETER AND DOSERATEMETER AGAINST 241Am–Be SOURCE—MONTE CARLO SIMULATION AND MEASUREMENTS

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