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Characterization neutron and gamma beams at the tangential beam port of TRIGA 2000 reactor was done in order to prepare the development of Prompt Gamma Neutron Activation Analysis (PGNAA) facility. Characterization was performed by simulation using Monte Carlo method with MCNPX and PHITS computer codes. The MCNPX code was used to simulate the neutr...
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... data [14]. To run the MCNPX code, some inputs are required. Those inputs are reactor geometry, reactor material composition, radiation source model, and tally flux. The TRIGA 2000 reactor has a complex geometry, so it is quite difficult in modeling. The model of reactor geometry covers the reactor core, reflector, and cooling water as shown in Fig. 1. The shape and size of the reactor parts were made by a geometry model in the MCNPX input. The material data and cross-sections of each reactor component were also made for the MCNPX input. The materials used are water, aluminum, SS 304, boron carbide, UZr-H fuel elements, zirconium, and ...
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... The foils are exposed to a neutron energy spectrum and the response of each one is calculated using the measured activity and known physical features of the foils. Computer software such as Monte Carlo N-Particle (MCNP) can be used to determine the initial energy spectrum [24,25], and Unfolding with MAXED and GRAVEL (UMG) can calculate the unfolded energy spectrum. ...
The Neutron Radiography Reactor at Idaho National Laboratory (INL) has two beamlines extending radially outward from the east and north faces of the reactor core. The control rod withdrawal procedure has recently been altered, potentially changing power distribution of the reactor and thus the properties of the neutron beams, calling for characterization of the neutron beams. The characterization of the East Radiography Station involved experiments used to measure the following characteristics: Neutron flux, neutron beam uniformity, cadmium ratio, image quality, and the neutron energy spectrum. The ERS is a Category-I neutron radiography facility signifying it has the highest possible rank a radiography station can achieve. The thermal equivalent neutron flux was measured using gold foil activation and determined to be 9.61 × 106 ± 2.47 × 105 n/cm2-s with a relatively uniform profile across the image plane. The cadmium ratio measurement was performed using bare and cadmium-covered gold foils and measured to be 2.05 ± 2.9%, indicating large epithermal and fast neutron content in the beam. The neutron energy spectrum was measured using foil activation coupled with unfolding algorithms provided by the software package Unfolding with MAXED and GRAVEL (UMG). The Monte-Carlo N-Particle (MCNP6) transport code was used to assist with the unfolding process. UMG, MCNP6, and measured foil activities were used to determine a neutron energy spectrum which was implemented into the MCNP6 model of the east neutron beam to contribute to future studies.
In this study, we present a validated Geant4 Monte Carlo simulation model of the Dingo thermal neutron imaging beamline at the Australian Centre for Neutron Scattering. The model, constructed using CAD drawings of the entire beam transport path and shielding structures, is designed to precisely predict the in-beam neutron field at the position at the sample irradiation stage. The model’s performance was assessed by comparing simulation results to various experimental measurements, including planar thermal neutron distribution obtained in-beam using gold foil activation and $$^{10}$$ 10 B $$_{4}$$ 4 C-coated microdosimeters and the out-of-beam neutron spectra measured with Bonner spheres. The simulation results demonstrated that the predicted neutron fluence at the field’s centre is within 8.1% and 2.1% of the gold foil and $$^{10}$$ 10 B $$_{4}$$ 4 C-coated microdosimeter measurements, respectively. The logarithms of the ratios of average simulated to experimental fluences in the thermal (E $$_{th}<$$ th < 0.414 eV), epithermal (0.414 eV < E $$_{epi}<$$ epi < 11.7 keV) and fast (E $$_{fast}>$$ fast > 11.7 keV) spectral regions were approximately − 0.03 to + 0.1, − 0.2 to + 0.15, and − 0.4 to + 0.2, respectively. Furthermore, the predicted thermal, epithermal and fast neutron components in-beam at the sample stage position constituted approximately 18%, 64% and 18% of the total neutron fluence.
