Radiation Facility Research Articles

Characterization of natural soda ash for dosimetry using thermoluminescence technique

Soda ash, due to its various use for industrial applications, is a phosphor likely to be found in the vicinities of radiation facilities where retrospective dosimetry may be required in the unlikely events of radiation accidents/incidents. The ash is therefore a potential material for retrospective dosimetry using luminescence techniques. In this report, the thermoluminescence characteristics of soda ash from Suan pan, Botswana are presented. The thermoluminescence glow curve of the soda ash consists three peaks near 79, 175 and 329 oC with a shoulder around 221oC. The peak intensities of the peaks and the whole glow curve integrated intensity are linear with dose. Tm-Tstop analysis reveals soda ash contains four peaks near 82, 211, 235 and 335 oC. The four peaks are affected by thermal quenching with activation energy of thermal quenching 0.64 eV, 0.29 eV, 0.66 eV and 0.29 eV respectively. The intensities of the peaks decrease with optical stimulation. The minimum dose the phosphor can measure is evaluated to be 0.34 Gy. The thermoluminescence from soda ash is suitable for dosimetry, especially for high dose measurement. The peak near 335oC with mean lifetime greater than 250 years is the most suitable for dosimetry. The phosphor may be able to produce phototransfer thermoluminescence.

Spectroscopic, calorimetric, and radiation shielding analysis of lead-free transparent dysprosium-doped phosphate glasses

Eco-friendly phosphate glasses with 50P2O5-(50 – x)BaO-xDy2O3 (x = 0, 0.5, 1.0, 2.0, 3.0, 4.0 mol %) compositions were prepared and studied focusing on their potential for radiation attenuation and shielding applications. The glasses were synthesized by melting and subsequently characterized by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR) spectroscopy, densitometry, refractive index, optical absorption, and differential scanning calorimetry (DSC). XRD confirmed the amorphous nature of the glasses, while FT-IR spectra indicated that the glass structure was preserved upon Dy2O3 inclusion. It was observed that both the density and refractive index generally increased with higher Dy2O3 content. Optical absorption data showed a linear increase in Dy3+ ion absorption with Dy2O3 concentration, confirming the effective incorporation of Dy3+ ions. Tauc and Urbach plots were also employed to analyze the absorption edges of the glasses. DSC thermograms revealed that the glass transition temperatures increased while glass stability improved with higher Dy2O3 content. The radiation shielding properties were assessed by evaluating parameters such as mass attenuation coefficients, linear attenuation coefficients, tenth value layer, mean free path, effective conductivity, and effective electron density against gamma-ray photons. Dysprosium doping was found to enhance gamma-ray shielding (from 1 keV to 100 GeV) based on theoretical methods. Additionally, the 3 mol % Dy2O3 doped sample exhibited greater fast neutron removal cross-sections. However, the undoped barium phosphate host demonstrated better stopping potential and lower projected ranges against ions (protons and carbon). Photon trajectories and dose attenuation properties were also investigated using the Particle and Heavy Ions Transport System (PHITS) Monte Carlo code, indicating that the Dy3+ doped lead-free transparent glass protects against ionizing radiation. Hence, the barium phosphate host and Dy3+-doped counterparts are attractive for use in ionizing radiation and nuclear facilities, such as hospitals, research centers, and industries.

Multiresolution Phase-Contrast Tomography on BM18, a New Beamline at the European Synchrotron Radiation Facility

Multiresolution Phase-Contrast Tomography on BM18, a New Beamline at the European Synchrotron Radiation Facility

Intelligent Control System for the Hard X-Ray Nanoprobe Beamline Beam Optimization Based on Automatic Evolution Algorithm and Expert System.

A synchrotron radiation beamline automatic optimization system has been used in the Shanghai Synchrotron Radiation Facility, improving the optimization efficiency, but it does not store and use the beamline adjusting experience, and cannot quickly optimize and store the experienced improvement. The expert system combined with an automatic evolutionary algorithm is used for intelligent beamline optimization; the algorithm initialization is optimized by invoking database experience, the convergence is quickly completed near the optimal solution, and the system's learning is improved by storing experience results. The software was designed on the EPICS (Version 3.15) platform, which was used to implement the algorithm in Python language, the expert database was developed with MongoDB tool (Version 4.0.27), and the upper application interface was designed with CSS software (Phoebus Version 4.7.2). The system was successfully tested on the BL13U hard X-ray nanoprobe beamline of Shanghai Synchrotron Radiation Facility. The results show that the maximum convergence time of a single objective with four-axis degrees of freedom is about 2 min, and the speed is increased by 15 times. The solution set obtained by using multi-objective two and four-axis degrees of freedom is better overall. The system can effectively improve the optimization efficiency and effect, and its universality can be extended to other synchrotron radiation devices and beamlines to promote the development of intelligent beamline modulation technology.

Mechanical properties and radiological implications of replacing sand with waste ceramic aggregate in ordinary concrete

The mining of aggregates for the production of concrete creates ecological problems. In this study, the effect of partially replacing sand as fine aggregate (FA) with waste ceramic tiles (WCT) on the density, compressive strength (CS), specific radioactivity of naturally occurring radioactive materials (238U, 232Th, and 40K), and the radiation shielding competence of concrete was investigated. Ordinary concrete samples consisting of cement, fine aggregate (river sand), coarse aggregate (granite), and water were prepared in 50 mm × 50 mm x 50 mm cubical steel moulds. The samples were coded as C-WCT0, C-WCT5, C-WCT10, C-WCT15, C-WCT20, and C-WCT25, representing concrete samples in which the FA component was replaced by 0, 5, 10, 15, 20, and 25% pulverized WCT, respectively. The CS and density of the samples were determined after 7-, 14-, and 28-day curing periods. The gamma spectrometric method was used to determine the specific activity of 238U, 232Th, and 40K using a hyper pure germanium detector. The photon and neutron shielding parameters of the concrete blocks were calculated with the aid of the EPICS2017 cross-section library and relevant standard formulae. The mean CS for each concrete category increase with curing age. The density of the concrete varied from 2213 kg/m3 to 2488 kg/m3 as the FA replacement level rose to 15%. Using WCT as a partial replacement for FA altered the chemical composition and decreased the specific activities of 238U, 232Th, and 40K, in the concrete samples. C-WCT15 had the best gamma photon and fast neutron absorption features among the concrete samples. The use of WCT as aggregate in concrete production is a sustainable and environmental-friendly way of producing concrete for general civil engineering and shielding applications in medical and other radiation facilities. This study also affirms that using alternative materials with lower specific activity to replace sand is radiologically desirable in reducing the indoor radiation dose of occupants of concrete-based structures. The replacement of 15% sand by WCT produced stronger, radiologically safer, and more effective radiation absorbing concrete.

Deep learning for 3D vascular segmentation in hierarchical phase contrast tomography: a case study on kidney

Automated blood vessel segmentation is critical for biomedical image analysis, as vessel morphology changes are associated with numerous pathologies. Still, precise segmentation is difficult due to the complexity of vascular structures, anatomical variations across patients, the scarcity of annotated public datasets, and the quality of images. Our goal is to provide a foundation on the topic and identify a robust baseline model for application to vascular segmentation using a new imaging modality, Hierarchical Phase-Contrast Tomography (HiP-CT). We begin with an extensive review of current machine-learning approaches for vascular segmentation across various organs. Our work introduces a meticulously curated training dataset, verified by double annotators, consisting of vascular data from three kidneys imaged using HiP-CT as part of the Human Organ Atlas Project. HiP-CT pioneered at the European Synchrotron Radiation Facility in 2020, revolutionizes 3D organ imaging by offering a resolution of around 20 μm/voxel and enabling highly detailed localised zooms up to 1–2 μm/voxel without physical sectioning. We leverage the nnU-Net framework to evaluate model performance on this high-resolution dataset, using both known and novel samples, and implementing metrics tailored for vascular structures. Our comprehensive review and empirical analysis on HiP-CT data sets a new standard for evaluating machine learning models in high-resolution organ imaging. Our three experiments yielded Dice similarity coefficient (DSC) scores of 0.9523, 0.9410, and 0.8585, respectively. Nevertheless, DSC primarily assesses voxel-to-voxel concordance, overlooking several crucial characteristics of the vessels and should not be the sole metric for deciding the performance of vascular segmentation. Our results show that while segmentations yielded reasonably high scores-such as centerline DSC ranging from 0.82 to 0.88, certain errors persisted. Specifically, large vessels that collapsed due to the lack of hydrostatic pressure (HiP-CT is an ex vivo technique) were segmented poorly. Moreover, decreased connectivity in finer vessels and higher segmentation errors at vessel boundaries were observed. Such errors, particularly in significant vessels, obstruct the understanding of the structures by interrupting vascular tree connectivity. Our study establishes the benchmark across various evaluation metrics, for vascular segmentation of HiP-CT imaging data, an imaging technology that has the potential to substantively shift our understanding of human vascular networks.

Influence of the gamma source on the radiolytic stability of N,N,N′,N′-tetra-n-octyl-diglycolamide (TODGA)

Abstract In nuclear reprocessing, hydrolytic and radiolytic stability of ligands, extractants, diluents and solvents is of particular importance. The strength of extraction systems can only be fully exploited when process conditions are predictable and essential molecules, which are in close proximity to radioactive isotopes, are resistant to the radiation. During the development of novel extraction systems, testing of the radiolytic stability is often evaluated by exposing the molecules to high energetic gamma rays. In this work, the influence of the source of gamma rays is evaluated. TODGA was irradiated from 0–500 kGy using different sources of gamma rays, and its degradation was followed using UPLC-HRMS. Pool-type gamma irradiation facilities BRIGITTE B (Co-60) and GEUSE II (spent nuclear fuel) at SCK CEN were employed to serve as gamma sources. In this work, it is found that there is no significant influence on TODGA degradation which can be attributed to the origin of the gamma source.

Beamtimes and knowledge production times: how big-science research infrastructures shape nations’ domestic and international science production

Frontier scientific discoveries increasingly rely on big-science research infrastructures, such as supercolliders, synchrotron light sources, and space telescopes, whose construction and operation involve intensive international collaboration. This collaborative nature, however, presents a challenge in balancing national interests with the common good, particularly given the substantial fiscal investments involved. This study investigates the effects of one of China’s prominent big-science infrastructures, the Shanghai Synchrotron Radiation Facility (SSRF), on the country’s production of science, differentiating between national and international scientific endeavors. Employing a rigorous difference-in-differences (DID) methodology, it evaluates SSRF’s effects on discipline-level production of publications by domestic researchers and those involving international collaboration. The empirical findings reveal compelling evidence that SSRF has significantly enhanced the production of high-impact national and international publications for disciplines reliant on the facility for experiments, particularly increasing the percentage of high-impact national publications. The findings also underscore the dual role of big-science infrastructures in fostering international research collaboration while simultaneously enhancing nations’ domestic scientific development and competitiveness. Additionally, the study provides valuable insights for research assessment and science policy discussions.

Study of a gel dosimeter based on Ag nanoparticles for applications in radiation therapy with synchrotron X-rays at ultrahigh dose rate compared to 60Co γ-rays

A silver nitrate (AgNO3) gel was developed and evaluated as a dosimeter for synchrotron X-ray-based studies in microbeam radiation therapy (MRT) and FLASH radiation therapy. The gel was irradiated at the European Synchrotron Radiation Facility (ID17 Biomedical beamline) with a continuous X-ray spectrum in the 50–600 keV range and a dose rate of 11.6 kGy/s. The spectrophotometric response after irradiation at this beamline was compared with the response at a conventional 60Co γ-ray source providing a dose rate of 0.27 Gy/s. Ag + ions in the gel dosimeter undergo reduction to Ago nanoparticles, as detected at 450 nm, which is a surface plasmon resonance band. The intensity of this band increased linearly with increasing absorbed dose up to 100 Gy, and improved with the addition of glycerol. The gel dosimeter exhibited the lowest detectable dose (LDD) of 75.9% lower and a dose deposition of 76% higher for ID17 beamline irradiation than for 60Co irradiation. The theoretical relative response HQ,Qo for the gel irradiated at the synchrotron was 1.70, which is in close agreement with the experimental relative response FQ,Qo = 1.76. These results confirm the dose enhancement in the gel irradiated with orthovoltage X-rays. The good properties of the silver nitrate gel, together with its increased sensitivity to orthovoltage X-ray irradiation and modest overall uncertainty of 5.8% (2σ), confirm that the gel is a valid dosimeter for measurements at ultrahigh dose rates for synchrotron radiotherapy. The dosimeter is also a promising candidate for dose enhancement factor measurements in nanoparticle-based radiotherapy techniques.

KATANA - water activation facility at JSI TRIGA, Part II: First experiments

Water as a primary coolant will play an important role in the performance of fusion reactors, as after being irradiated and activated, it causes an ionising radiation field throughout the facility. In direct support of ITER, the KATANA irradiation facility, which utilises a closed-water activation loop and serves as a well-defined and stable high-energy γ and neutron source, was commissioned in 2024 at the TRIGA Mark II research reactor at the Jožef Stefan Institute in Slovenia.A series of first experiments using the KATANA irradiation facility were performed to determine the operational characteristics of the KATANA, i.e. characterisation of the neutron flux within the irradiation component, dose rate measurements, spectrum characterisation of the activated water, and response to a change in reactor power & flow rate. The KATANA facility demonstrated the desired operational characteristics in terms of high and stable water flow rates and high activity values of the observed isotopes 16N, 17N and 19O, which is essential for minimising the experimental uncertainties.The first experiments performed at KATANA provided in-depth knowledge into the operation and capabilities of the facility and essential data to serve as a basis for further, more detailed/benchmark experiments.

Analysis of microcracking processes in microconcrete under confined compression utilising synchrotron-based ultra-high speed X-ray phase contrast imaging

In the present study, microconcrete (MC) samples were exposed to dynamic quasi-oedometric compression (QOC) tests and visualised in-situ by the means of MHz synchrotron X-ray phase-contrast imaging in the ESRF synchrotron in order to analyse the damage mechanisms governing the mechanical behaviour of concrete under high-strain-rate confined compression. To do so, small cylindrical samples were placed in polymeric confinement cell and dynamically compressed along their axial direction using SHPB (Split-Hopkinson Pressure Bar) set-up available in ID19 beamline in the European Synchrotron Radiation Facility (ESRF). The damage process was visualized with MHz X-ray phase-contrast imaging along with an ultra-high-speed camera operating at a recording frequency approximately 1 Mfps (million frames per second i.e., 880 ns interframe time). The axial stress and strain temporal profiles were obtained from standard Kolsky's (SHPB) data processing. In addition, data of radial stress and strain within the sample were deduced from non-linear analysis of the mechanical behaviour of the polycarbonate confining cell instrumented with a strain gauge. Finally, the onset and growth of microcracking observed from the equatorial zone of large spherical pores is correlated with deviatoric and pressure measurements showing how the pore collapse process develops during the applied mechanical loading.

Establishment of an absolute measurement of the reference air kerma rate for HDR 192Ir brachytherapy sources

Before this study, no institution in China had undertaken the calculation and official establishment of reference values for the reference air kerma rate associated with high-dose rate 192Ir sources used in brachytherapy. This research, carried out at the National Institute of Metrology (NIM) in China, has successfully established an 192Ir reference radiation facility. Consequently, it has achieved the absolute measurement of the reference air kerma rate for high-dose rate brachytherapy using 192Ir sources. For this study, a medical afterloader machine was acquired. The radiation source employed was a high-dose rate 192Ir source for brachytherapy, produced by HTA Co., Ltd. A reference graphite cavity ionization chamber with a volume of 100 cm3 was designed to serve as the ionization chamber for absolute measurements. The determination of various correction factors and physical constants was achieved through a method that combines Monte Carlo simulations with experimental techniques. The study successfully accomplished the absolute measurement of the reference air kerma rate for the high-dose rate brachytherapy 192Ir radiation source. The expanded uncertainty of the measurement results was 0.72% (k = 2). The relative standard deviation for the RAKR of the same 192Ir radiation source was 0.073%. This study marks a significant advancement in the field of radiation therapy in China, particularly in the accurate dosimetry for brachytherapy using high-dose rate 192Ir sources. The study will contribute to the BIPM.RI(I)-K8 international comparison, organized by the Bureau International des Poids et Mesures (BIPM), thus facilitating the international recognition of the measurement values.

Advanced soft tissue visualization in conjunction with bone structures using contrast-enhanced micro-CT.

Micro-computed tomography (CT) analysis of soft tissues alongside bone remains challenging due to significant differences in X-ray absorption, preventing spatial inspection of bone remodeling including the cellular intricacies of mineralized tissues in developmental biology and pathology. The goal was to develop a protocol for contrast-enhanced micro-CT imaging that effectively visualizes soft tissues and cells in conjunction with bone while minimizing bone attenuation by decalcification. Murine femur samples were decalcified in ethylenediaminetetraacetic acid and treated with three different contrast agents: (i)iodine in ethanol, (ii)phosphotungstic acid in water, and (iii)Lugol's iodine. Micro-CT scans were performed in the laboratory setup SkyScan 1172 and at the synchrotron radiation for medical physics beamline in synchrotron radiation facility Elettra. Soft and hard tissue contrast-to-noise ratio (CNR) and contrast efficiency after decalcification were measured. In laboratory micro-CT, Lugol's iodine demonstrated a threefold higher CNR in the bone marrow, representing the soft tissue portion, compared with the bone. Contrast efficiencies, measured in synchrotron micro-CT, were consistent with these findings. Higher resolutions and the specificity of Lugol's iodine to cellular structures enabled detailed visualization of bone-forming cells in the epiphyseal plate. The combination of decalcification and the utilization of the contrast agent Lugol's iodine facilitated an enhanced soft tissue visualization in conjunction with bone.

A miniature X-ray diffraction setup on ID20 at the European Synchrotron Radiation Facility.

We describe an ultra-compact setup for in situ X-ray diffraction on the inelastic X-ray scattering beamline ID20 at the European Synchrotron Radiation Facility. The main motivation for the design and construction of this setup is the increasing demand for on-the-fly sample characterization, as well as ease of navigation through a sample's phase diagram, for example subjected to high-pressure and/or high-temperature conditions. We provide technical details and demonstrate the performance of the setup.

Assessment of the Degree Of DNA Methylation in Lymphocytes аfter а Single Blood Irradiation in vitro

DNA methylation is one of the processes of epigenetic regulation of the genome, which is sensitive to the influence of endogenous and exogenous factors. The effect of ionizing radiation on the genome is accompanied by a change in the degree of DNA methylation, which can be dose-dependent and persist for a long time after radiation exposure. The objective of the study was to assess the degree of DNA methylation of blood lymphocytes after a single exposure to gamma radiation at a dose of 1.5 Gy using wide-genome bisulfite sequencing. The study included 10 conditionally healthy male employees of the ionizing radiation facility who were not exposed to radiation and did not suffer from chronic diseases. The material was whole blood: 0 Gy (control samples) and 1.5 Gy (experimental samples irradiated with gamma radiation). After irradiation with subsequent cultivation of whole blood, DNA isolation and bisulfite sequencing of limited sets of genomic loci (Reduced representation bisulfite sequencing) was performed using XmaI restriction enzyme (XmaI-RRBS). 41 genes were identified, including 26 genes (HOXD4, PADI2, FOXK1, FTCD, PRDM16, TOM1, PPP1R14A, FLNB, OR1F1, RARA, CRTAC1, AP5B1, ARL5C, NOC2L, MAMDC4, FGFRL1, PPFIA3, CUX2, ANKRD20A19P, FAM83H-AS1, CBFA2T3, POLN, MIR4458HG, FNBP1, SPIRE2, and ZSCAN10) have a tendency to hypomethylation DNA, and another 15 genes (CHRNA4, SEPTIN9, ZNF174, ELK3, NFAM1, ALG10, SOX8, KLHL30, URI1, HBZ, KLF14, MYO16, MYEOV, DMKN, and PAX7) tend to have hypermethylated state detected in at least 50٪ of the experimental samples. Thus, the genes identified in this study can be promising markers of radiation exposure and, in the future, be used to develop a new type of biological dosimetry – epigenomic dosimetry of personnel in contact with ionizing radiation sources in the course of their professional activities.

Association of WNT Gene Polymorphism with Frequency of Cytogenetic Disorders under the Action of Ionizing Radiation

The paper presents the results of a study of the association of single nucleotide polymorphisms of the WNT genes with an increased frequency of cytogenetic disorders in the blood lymphocytes of workers at an ionizing radiation facility exposed to long-term radiation exposure at doses of 100–500 mGy.The object of the study was the blood of 95 apparently healthy workers who were subjected to long-term technogenic external exposure to γ-radiation in doses from 100 to 500 mGy in the course of their professional activities. For all examined individuals, a standard cytogenetic analysis of blood lymphocytes was performed. Genomic DNA was isolated from workers’ blood lymphocytes using a “QIAamp DNA Blood mini Kit” (Qiagen, Germany). DNA was genotyped for 116 single nucleotide polymorphisms of the WNT genes using high-density “CytoScan™ HD Array” (Affymetrix, USA) chips (DNA chips). Taking into account the Bonferroni correction, an association of single nucleotide polymorphisms of the WNT genes with a high frequency of circular chromosomes in blood lymphocytes was established, all other types of cytogenetic disorders did not show statistical significance. As a result of the study, a single nucleotide polymorphism of the WNT9B gene rs1530364 was identified, which can be considered as a potential marker of individual radiosensitivity.

Time varying flat field correction of X-ray microtomography with an improved deep-learning method.

In X-ray microtomography, the flat field image is usually needed to normalize the collected sample projections. Owing to the high brightness of the synchrotron radiation facility, dynamic CT imaging of in-situ or in-operando processes is broadly employed for the investigation of three-dimensional microstructure evolution. However, the fast, continuous data acquisition and the heavy, bulky in-situ devices usually prevent the easy collection of accurate flat field images, which means that conventional flat field correction is hard to efficiently correct the artefacts of X-ray microtomography. We report a deep-learning-based artefact correction method for X-ray microtomography, which uses flat field generated from each CT projection by an improved pix2pixHD model. Experimental results demonstrated that the proposed method has a significant advantage over the conventional method and available deep-learning-based flat field correction method for the flat field correction of projection images. The CT imaging results show that the proposed method efficiently reduces the systematic error during the intensity normalization process, and the CT reconstruction is improved significantly. Therefore, the method developed in this paper is applicable for the flat field correction of dynamic CT. Furthermore, experiments with a set of low Z material samples verified the generalization of the deep-learning-based method for a variety of samples never used for network training. In conclusion, the method developed in this paper is practicable for the flat field correction of in-situ CT imaging of dynamic processes and is also applicable to new samples as long as the neural network model is effectively trained.

In situ/operando method for energy stability measurement of synchrotron radiation.

A novel in situ/operando method is introduced to measure the photon beam stability of synchrotron radiation based on orthogonal diffraction imaging of a Laue crystal/analyzer, which can decouple the energy/wavelength and Bragg angle of the photon beam using the dispersion effect in the diffraction process. The method was used to measure the energy jitter and drift of the photon beam on BL09B and BL16U at the Shanghai Synchrotron Radiation Facility. The experimental results show that this method can provide a fast way to measure the beam stability of different light sources including bending magnet and undulator with meV-level energy resolution and ms-level time response.

Development of hard X-ray photoelectron spectroscopy in liquid cells using optimized microfabricated silicon nitride membranes.

We present first hard X-ray photoelectron spectroscopy (HAXPES) results of aqueous salt solutions and dispersions of gold nanoparticles in liquid cells equipped with specially designed microfabricated thin silicon nitride membranes, with thickness in the 15-25 nm range, mounted in a high-vacuum-compatible environment. The experiments have been performed at the HAXPES endstation of the GALAXIES beamline at the SOLEIL synchrotron radiation facility. The low-stress membranes are fabricated from 100 mm silicon wafers using standard lithography techniques. Platinum alignment marks are added to the chips hosting the membranes to facilitate the positioning of the X-ray beam on the membrane by detecting the corresponding photoemission lines. Two types of liquid cells have been used, a static one built on an Omicron-type sample holder with the liquid confined in the cell container, and a circulating liquid cell, in which the liquid can flow in order to mitigate the effects due to beam damage. We demonstrate that the membranes are mechanically robust and able to withstand 1 bar pressure difference between the liquid inside the cell and vacuum, and the intense synchrotron radiation beam during data acquisition. This opens up new opportunities for spectroscopic studies of liquids.

Preliminary study of a compact epithermal neutron absolute flux intensity measurement system for real-time in-vivo dose monitoring in boron neutron capture therapy

Boron neutron capture therapy (BNCT) is a radiotherapy technology that selectively kills tumor cells via the 10B(n, α)7Li reactions. Epithermal neutrons (0.5 eV–10 keV) are emitted and converted into thermal neutrons, which have a larger neutron capture reaction cross-section, by slowing down in the human body before reaching the tumor. Recently, the development of an epithermal neutron absolute flux intensity measurement technique has become crucial for real-time in-vivo dose monitoring in BNCT. In this study, a concept for a measurement system consisting of multiple compact scintillator with optical fibers detectors covered with neutron absorbers of various thicknesses is proposed. The designed system achieves a consistent response to epithermal neutrons with a theoretical coefficient of variation not higher than 5% for both LiCAF and EJ-254 scintillators. The theoretical feasibility of the proposed measurement system was investigated by an irradiation experiment carried out at the heavy water neutron irradiation facility at the Kyoto University Reactor. The experimental results indicated that further improvement and refinement are necessary to meet the high accuracy and precision required for real-time dose monitoring in clinical applications.