Experimental evaluation of the Geant4-calculated response functions of a Bonner sphere spectrometer on monoenergetic neutron sources

Hu, Z.; Zheng, Yuanshui; Tieshuan, Fan; Cui, Zhiqiang; Chen, J.; Zhang, H.; Gorini, G.; Zhao, Quan

doi:10.1016/j.nima.2020.163836

Cited by 11 publications

(5 citation statements)

References 17 publications

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“…Geant4.10.7 code [25,26] was employed to verify the design of the facility and the calculation of parameters such as energy, angular and spatial distribution, etc. The effectiveness of the code in simulating neutron transport processes has been demonstrated in the existing literature [27,28]. The neutron high precision model was used for neutron transportation under 20 MeV.…”

Section: Monte Carlo Simulation Methodsmentioning

confidence: 99%

Thermal neutron reference radiation facility with high thermalization and large uniformity area

Wang,

Yang,

et al. 2023

Metrologia

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A new thermal neutron facility based on 12 241Am-Be neutron sources has been established at the National Institute of Metrology, China. It has two independent irradiation fields, the Inner field and Outer field, constructed with high-purity graphite and heavy water as moderators, respectively. Three innovative designs, including the reflection cavity, reflection layer, and homogenizing lens, were introduced to improve the performance of the facility. The reflection layer can increase the thermal neutron fluence rate by about 3~4 times, the reflection cavity also enhances thermal fluence by 3~4 times by taking advantage of multiple scattering of neutrons, and the homogenizing lens mounted on the neutron exit surface of the moderator improve the distribution of thermal neutron. The characteristics of the two fields were investigated by Monte Carlo simulations and experimental measurements. The results show that the new facility has high thermalization and large uniformity area with these innovative designs. For the Inner field, the thermal neutron fluence rate at the reference position is (21433.3 ± 407.2) cm−2∙s−1, the cadmium ratio is 20.6, the nonuniformity is 0.1% over the 40 cm × 40 cm region. For the Outer field, the thermal fluence rate at the reference position is (2046.0 ± 49.1) cm−2∙s−1, the cadmium ratio is 1433, and the nonuniformity is 0.7% in the 70 cm × 70 cm region. The facility is expected to be suitable for the large-size detector, and its excellent performance is attractive for various thermal neutron experiments.

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Section: Monte Carlo Simulation Methodsmentioning

confidence: 99%

Thermal neutron reference radiation facility with high thermalization and large uniformity area

Wang,

Yang,

et al. 2023

Metrologia

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“…The spherical 3 He proportional counter (LND27036) used in this work has an inner diameter of 49.78 mm and an outer diameter of 50.8 mm, and is filled with a mixture of 97% 3 He and 3% CO 2 gases at a pressure of 5.065 × 10 5 Pa. The spherical structure of 3 He proportional counters are conducive to improving the neutron responses and reducing the angle dependence of the incident neutrons [14,15]. The PE-only spheres were selected based on the simulated response functions of the peaks to be at different energy positions, and the outer diameters of PE moderators ranged from 76 mm (3 inches) to 356 mm (14 inches).…”

Section: The Description Of the Ebss Systemmentioning

confidence: 99%

“…Therefore, a set of Extended-range Bonner sphere spectrometer (EBSS) encased in high atomic number shells has been developed, promising to measure the neutron spectra of the high energy radiation fields in CiADS. In addition, the neutron dose equivalents in the CiADS radiation fields can be accurately determined with the corresponding energy-dependent flux-dose conversion coefficients [7,[10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Calibration and validation measurements of the Extended-range Bonner sphere spectrometer

Gong,

Wen,

Luo

et al. 2024

J. Inst.

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An Extended-range Bonner sphere spectrometer (EBSS) has been developed to investigate the neutron spectra of the China initiative Accelerator Driven System. This paper presents the design, calibration, and validation measurements of the EBSS system using a standard 241Am-Be neutron source and the cosmic ray neutrons. The EBSS system was simulated using the PHITS code, and the geometric structures were designed using the response functions obtained by simulations. The EBSS system comprises of seven polyethylene-only spheres and seven extended-range spheres encased in lead, copper, or tungsten shells along with a bare 3He proportional counter. To verify the accuracy of the simulated response functions, the EBSS system was calibrated with monoenergetic neutron beams of 565 keV at the China Institute of Atomic Energy in Beijing. The EBSS system was used to measure neutron count rates of the 241Am-Be neutron source and cosmic ray neutrons. Subsequently, the measured neutron count rates were converted into neutron spectra by the unfolding software. Experimental findings demonstrate the precise capability of the EBSS system to measure neutron spectra across a wide range of neutron radiation fields.

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“…e Monte Carlo method can deal with complex geometric structures, material composition, and source terms, by simulating the real particle transport process, such as scattering, transmission, and absorption. Widely used software based on the Monte Carlo method includes MCNP [7][8][9], FLUKA (http://www.fluka.org/fluka.php; [10], GEANT4 [11,12], and so on. However, the Monte Carlo method usually requires a longer calculation time.…”

Section: Introductionmentioning

confidence: 99%

Shielding Design and Dose Evaluation for HTR-PM Fuel Transport Pipelines by QAD-CGA Program

Cao

Luo

et al. 2021

Science and Technology of Nuclear Installations

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The spherical fuel elements are adopted in the high-temperature gas-cooled reactor pebble-module (HTR-PM). The fuel elements will be discharged continuously from the reactor core and transported into the fuel transport pipelines during the reactor operation, leading to spatially varying dose outside the pipeline. In this case, the dose evaluation faces two major challenges, including dynamic source terms and pipelines with varying lengths and shapes. This study tries to handle these challenges for HTR-PM through comprehensive calculations using the QAD-CGA program and to design the corresponding shielding of the pipeline. During the calculation, it is assumed that a spherical fuel element stays in different positions of the pipelines in turn, and the corresponding dose contributions were calculated. By integrating the dose contributions at different positions, the dose at the points of interest can be obtained. The total dose is further determined according to the assumed fuel elements transport speed of 5 m/s and total 6000 fuel elements transportation per day. Two types of fuel transport pipelines and two source terms were considered, i.e., the spent fuel element transport pipelines with corresponding spent fuel source term and the different burn-up fuel element transport pipelines with the average burn-up fuel source term. Doses at different points of interest were calculated with no shielding scenario and with lead shielding of different thicknesses scenario. To evaluate the shielding effect, the dose limit of the orange radiation zone of HTR-PM and the radiation damage thresholds from NCRP report No.51 were both adopted. The calculated results show that, for pipelines that transport the spent fuel, a 4 cm lead shielding will be enough. And for pipelines that transport fuel elements with different burn-up, a 5 cm lead shielding will be added. The method and results can provide valuable reference for other work of HTR-PM.

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Experimental evaluation of the Geant4-calculated response functions of a Bonner sphere spectrometer on monoenergetic neutron sources

Cited by 11 publications

References 17 publications

Thermal neutron reference radiation facility with high thermalization and large uniformity area

Thermal neutron reference radiation facility with high thermalization and large uniformity area

Calibration and validation measurements of the Extended-range Bonner sphere spectrometer

Shielding Design and Dose Evaluation for HTR-PM Fuel Transport Pipelines by QAD-CGA Program

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