Magan, D. L. P., Caballero, L., Domingo-Pardo, C., Agramunt-Ros, J., Albiol, F., Casanovas, A., et al. (2016). First tests of the applicability of gamma-ray imaging for background discrimination in time-of-flight neutron capture measurements. Nucl. Instrum. Methods Phys. Res. A, 823, 107–119.
Abstract: In this work we explore for the first time the applicability of using gamma-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr3 scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a Au-197 sample have been carried out at n_TOF, achieving an enhancement of a factor of two in the signal-to-background ratio when selecting only those events coming from the direction of the sample.
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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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Labiche, M. et al, Caballero, L., & Rubio, B. (2010). TIARA: A large solid angle silicon array for direct reaction studies with radioactive beams. Nucl. Instrum. Methods Phys. Res. A, 614(3), 439–448.
Abstract: A compact, quasi-4 pi position sensitive silicon array. TIARA, designed to study direct reactions induced by radioactive beams in inverse kinematics is described here. The Transfer and Inelastic All-angle Reaction Array (TIARA) consists of 8 resistive charge division detectors forming an octagonal barrel around the target and a set of double-sided silicon-strip annular detectors positioned at each end of the barrel. The detector was coupled to the gamma-ray array EXOGAM and the spectrometer VAMOS at the GANIL Laboratory to demonstrate the potential of such an apparatus with radioactive beams. The N-14(d,p)N-15 reaction, well known in direct kinematics, has been carried out in inverse kinematics for that purpose. The observation of the N-15 ground state and excited states at 7.16 and 7.86 MeV is presented here as well as the comparison of the measured proton angular distributions with DWBA calculations. Transferred l-values are in very good agreement with both theoretical calculations and previous experimental results obtained in direct kinematics.
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Jordan, D. et al, Algora, A., Tain, J. L., Rubio, B., Agramunt, J., Perez-Cerdan, A. B., et al. (2013). Total absorption study of the beta decay of Tc-102,Tc-104,Tc-105. Phys. Rev. C, 87(4), 044318–14pp.
Abstract: The beta-feeding probabilities for three important contributors to the decay heat in nuclear reactors, namely Tc-102,Tc-104,Tc-105, have been measured using the total absorption spectroscopy technique. For the measurements, sources of very high isobaric purity have been obtained using a Penning trap (JYFLTRAP). A detailed description of the data analysis is given and the results are compared with high-resolution measurements and theoretical calculations. DOI: 10.1103/PhysRevC.87.044318
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Catford, W. N. et al, Caballero, L., & Rubio, B. (2010). Migration of Nuclear Shell Gaps Studied in the d(Ne-24, p gamma)Ne-25 Reaction. Phys. Rev. Lett., 104(19), 192501–4pp.
Abstract: The transfer of neutrons onto Ne-24 has been measured using a reaccelerated radioactive beam of Ne-24 to study the (d, p) reaction in inverse kinematics. The unusual raising of the first 3/2(+) level in Ne-25 and its significance in terms of the migration of the neutron magic number from N = 20 to N = 16 is put on a firm footing by confirmation of this state's identity. The raised 3/2(+) level is observed simultaneously with the intruder negative parity 7/2(-) and 3/2(-) levels, providing evidence for the reduction in the N = 20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2(+) state shows that the established USD shell model breaks down well within the sd model space and requires a revised treatment of the proton-neutron monopole interaction.
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