n_TOF Collaboration(Alcayne, V. et al), Babiano-Suarez, V., Caballero-Ontanaya, L., Domingo-Pardo, C., Ladarescu, I., & Tain, J. L. (2026). Measurement of the 244Cm neutron capture cross section at the n_TOF facility at CERN. Ann. Nucl. Energy, 227, 111977–14pp.
Abstract: Accurate neutron capture cross section data for minor actinides are essential for the safe and efficient management of high level radioactive waste produced during the operation of nuclear reactors. In particular, Cm-244, with a half-life of 18.11 years, dominates neutron emission in spent fuel and also contributes significantly to the decay heat and radiotoxicity. Furthermore, neutron capture on Cm-244 opens the pathway for the formation of heavier isotopes such as Bk, Cf, and other Cm isotopes. Sensitivity studies for present and future nuclear reactors have highlighted the need to reduce the uncertainties in the Cm-244 capture cross section. Experimental data on the capture cross section of this isotope are scarce due to the challenges associated with its measurements. Prior to the presented measurement and two recent measurements conducted at J-PARC, only one set of data for the Cm-244 capture cross section existed, obtained in 1969 during an underground nuclear explosion experiment. The capture cross section of Cm-244 has been measured at the nTOF facility at CERN with three different experimental setups: one at Experimental Area 1 (EAR1) using the Total Absorption Calorimeter and two measurements at Experimental Area 2 (EAR2) with C6D6 detectors, employing two different samples. The results from these three measurements were found to be compatible and then combined. In total, 17 resonances of Cm-244 were measured at nTOF below 300 eV. The radiative kernels obtained in this measurement are in good agreement with JENDL-4.0 for the majority of the resonances. Additionally, they are compatible with the recent JENDL-5 library below 50 eV, while at higher energies, the majority of radiative kernels from this evaluation based on the recent measurement by Kawase et al., are not compatible. Additionally, the Cm-244 samples also contained Pu-240. Resonances of this isotope were analyzed in the energy range between 20 and 180 eV, and the results were found to be consistent with previous measurements and evaluations, that enhances confidence in the Cm-244 results.
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Torres-Sanchez, P., Lerendegui-Marco, J., Balibrea-Correa, J., Babiano-Suarez, V., Gameiro, B., Ladarescu, I., et al. (2025). The potential of the i-TED Compton camera array for real-time boron imaging and determination during treatments in Boron Neutron Capture Therapy. Appl. Radiat. Isot., 217, 111649–9pp.
Abstract: This paper explores the adaptation and application of i-TED Compton imagers for real-time dosimetry in Boron Neutron Capture Therapy (BNCT). The i-TED array, previously utilized in nuclear astrophysics experiments at CERN, is being optimized for detecting and imaging 478 keV gamma-rays, critical for accurate BNCT dosimetry. Detailed Monte Carlo simulations were used to optimize the i-TED detector configuration and enhance its performance in the challenging radiation environment typical of BNCT. Additionally, advanced 3D image reconstruction algorithms, including a combination of back-projection and List-Mode Maximum Likelihood Expectation Maximization (LM-MLEM), are implemented and validated through simulations. Preliminary experimental tests at the Institut Laue-Langevin (ILL) demonstrate the potential of i-TED in simplified conditions, with ongoing experiments focusing on testing imaging capabilities in realistic BNCT conditions.
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Lerendegui-Marco, J., Hallam, J., Cisterna, G., Sanchis-Molto, A., Balibrea-Correa, J., Babiano-Suarez, V., et al. (2025). First experimental results and optimization study of the portable neutron-gamma imager GN-Vision. Appl. Radiat. Isot., 224, 111826–13pp.
Abstract: GN-Vision is a compact, dual-modality imaging device designed to simultaneously localize the spatial origin of y-ray and slow neutron sources, with potential applications in nuclear safety, security, and hadron therapy. The system utilizes two position-sensitive detection planes, combining Compton imaging techniques for yray visualization with passive collimation for imaging slow and thermal neutrons (energies below 100 eV). This paper presents the first experimental outcomes from the initial GN-Vision prototype, focused on the development of its neutron imaging capabilities. Following this experimental assessment, we explore the device's performance potential and discuss several Monte Carlo simulation-based optimizations aimed at refining the neutron collimation system. These optimizations seek to improve real-time imaging efficiency and cost-effectiveness, enhancing GN-Vision's applicability for future practical deployments.
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Lerendegui-Marco, J., Balibrea-Correa, J., Alvarez-Rodriguez, P., Babiano-Suarez, V., Gameiro, B., Ladarescu, I., et al. (2025). First pilot tests of Compton imaging and boron concentration measurements in BNCT using i-TED. Appl. Radiat. Isot., 225, 112009–9pp.
Abstract: Dosimetry in BNCT poses significant challenges due to the indirect effect of neutrons interacting with elements within the body and uncertainties associated with the uptake of boron compounds used in clinical practice. Current treatment planning relies on unconventional estimates of boron tumor uptake derived from prior PET scans and thus, an online boron-uptake monitor would be highly convenient. This work presents the first pilot experiments carried out at ILL-Grenoble with the high-efficiency Compton camera i-TED, hereby aiming at demonstrating its applicability for BNCT dosimetry by introducing real-time measurement of the boron concentration and imaging capabilities of spatial dose distribution. In this experiment, we measured the 10B uptake of different cancer cells of tongue squamous cell carcinoma, malignant melanoma and glioblastoma treated with BPA (80 ppm of 10B). The samples were irradiated with the thermal neutron spectrum of ILL-Grenoble and the 478 keV 1-rays from the 7Li de-excitation after the neutron-boron reaction were registered both with the Compton imager and the high-sensitivity FIPPS HPGe array. These series of measurements allowed us to demonstrate the imaging capabilities of the Compton imaging device for the 478 keV 1-rays of interest for dosimetry in BNCT, as well as to assess its sensitivity, which was found to be below 1 μg of 10B.
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n_TOF Collaboration(Michalopoulou, V. et al), Balibrea-Correa, J., Domingo-Pardo, C., Ladarescu, I., Lerendegui-Marco, J., & Tarifeño-Saldivia, A. (2025). Measurement of the 235U fission cross section relative to the standard 10B(n, α) reaction at the CERN n_TOF facility: Results for En < 2 eV. Appl. Radiat. Isot., 226, 112063–7pp.
Abstract: The neutron induced fission of U-235 is a very important reaction for nuclear technology applications and for the design of future systems to produce clean and safe energy. In addition, it is used as a reference reaction for neutron cross-section measurements, thus, its cross section is needed with a high accuracy over a wide energy range. In this work, the measurement for the U-235(n,f) reaction was carried out at the n_TOF facility located at CERN, at experimental area EAR-2. The standard B-10(n, alpha) reaction was used as reference, while a setup based on the gaseous Micromegas detectors was implemented for the detection of the fission fragments and alpha and 7Li-particles of the two reactions, respectively. In order to determine the thickness of the B-10 sample NRA measurements were carried out at the National Center for Scientific Research ''Demokritos''.
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n_TOF Collaboration(Patronis, N. et al), Babiano-Suarez, V., Balibrea-Correa, J., Domingo-Pardo, C., Ladarescu, I., & Lerendegui-Marco, J. (2023). Status report of the n_TOF facility after the 2nd CERN long shutdown period. EPJ Tech. Instrum., 10(1), 13–10pp.
Abstract: During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the nTOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the nTOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported.
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Lerendegui-Marco, J., Babiano-Suarez, V., Balibrea-Correa, J., Caballero, L., Calvo, D., Ladarescu, I., et al. (2024). Simultaneous Gamma-Neutron Vision device: a portable and versatile tool for nuclear inspections. EPJ Tech. Instrum., 11(1), 2–17pp.
Abstract: This work presents GN-Vision, a novel dual gamma-ray and neutron imaging system, which aims at simultaneously obtaining information about the spatial origin of gamma-ray and neutron sources. The proposed device is based on two position sensitive detection planes and exploits the Compton imaging technique for the imaging of gamma-rays. In addition, spatial distributions of slow- and thermal-neutron sources (<100 eV) are reconstructed by using a passive neutron pin-hole collimator attached to the first detection plane. The proposed gamma-neutron imaging device could be of prime interest for nuclear safety and security applications. The two main advantages of this imaging system are its high efficiency and portability, making it well suited for nuclear applications were compactness and real-time imaging is important. This work presents the working principle and conceptual design of the GN-Vision system and explores, on the basis of Monte Carlo simulations, its simultaneous gamma-ray and neutron detection and imaging capabilities for a realistic scenario where a Cf-252 source is hidden in a neutron moderating container.
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Babiano-Suarez, V. et al, Lerendegui-Marco, J., Balibrea-Correa, J., Caballero, L., Calvo, D., Ladarescu, I., et al. (2021). Imaging neutron capture cross sections: i-TED proof-of-concept and future prospects based on Machine-Learning techniques. Eur. Phys. J. A, 57(6), 197–17pp.
Abstract: i-TED is an innovative detection system which exploits Compton imaging techniques to achieve a superior signal-to-background ratio in (n, gamma) cross-section measurements using time-of-flight technique. This work presents the first experimental validation of the i-TED apparatus for high-resolution time-of-flight experiments and demonstrates for the first time the concept proposed for background rejection. To this aim, the Au-197(n, gamma) and Fe-56(n, gamma) reactions were studied at CERN n_TOF using an i-TED demonstrator based on three position-sensitive detectors. Two C6D6 detectors were also used to benchmark the performance of i-TED. The i-TED prototype built for this study shows a factor of similar to 3 higher detection sensitivity than state-of-the-art C6D6 detectors in the 10 keV neutron-energy region of astrophysical interest. This paper explores also the perspectives of further enhancement in performance attainable with the final i-TED array consisting of twenty position-sensitive detectors and newanalysis methodologies based on Machine-Learning techniques.
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n_TOF Collaboration(Domingo-Pardo, C. et al), Babiano-Suarez, V., Balibrea-Correa, J., Caballero, L., Ladarescu, I., Lerendegui-Marco, J., et al. (2023). Advances and new ideas for neutron-capture astrophysics experiments at CERN n_TOF. Eur. Phys. J. A, 59(1), 8–11pp.
Abstract: This article presents a few selected developments and future ideas related to the measurement of (n, gamma ) data of astrophysical interest at CERN n_TOF. The MC-aided analysis methodology for the use of low-efficiency radiation detectors in time-of-flight neutron-capture measurements is discussed, with particular emphasis on the systematic accuracy. Several recent instrumental advances are also presented, such as the development of total-energy detectors with gamma- ray imaging capability for background suppression, and the development of an array of small-volume organic scintilla tors aimed at exploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics prospects related to the intermediate i neutron-capture process of nucleosynthesis are discussed in the context of the new NEAR activation area.
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Tagliente, G. et al, Babiano-Suarez, V., Domingo-Pardo, C., Ladarescu, I., & Tain, J. L. (2024). High-resolution cross section measurements for neutron interactions on 89Y with incident neutron energies up to 95 keV. Eur. Phys. J. A, 60(1), 21–18pp.
Abstract: The cross section of the Y-89(n,gamma) reaction has important implications in nuclear astrophysics and for advanced nuclear technology. Given its neutron magic number N = 50 and a consequent small neutron capture crosssection,89Y represents one of the key nuclides for the stellars-process. It acts as a bottleneck in the neutron capture chain between the Fe seed and the heavier elements. Moreover, it is located at the overlapping region, where both the weak and mains-process components take place.Y-89, the only stable yttrium isotope, is also used in innovative nuclear reactors. Neutron capture and transmission measurements were per-formed at the time-of-flight facilities n_TOF at CERN and GELINA at JRC-Geel. Resonance parameters of individual resonances were extracted from a resonance analysis of the experimental transmission and capture yields, up to a neutron incident energy of 95 keV. Even though a comparison with results reported in the literature shows differences in resonance parameters, the present data are consistent with the Maxwellian averaged cross section suggested by the astro-physical database KADoNiS.
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