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Stefanini, A. M. et al, Deltoro, J. M., Gadea, A., Perez-Vidal, R. M., & Valiente Dobon, J. J. (2026). Fusion of 12C+28Si at deep sub-barrier energies. Phys. Lett. B, 872, 140084–8pp.
Abstract: The sub-barrier fusion hindrance phenomenon is systematically observed in heavy-ion systems, but its evidence for light-mass cases of astrophysical interest, like C+C, C+O and O+O, is controversial. Their low-energy behaviour may be clarified by studying slightly heavier systems, so to extrapolate their trend to the lighter cases. In this work, fusion of C-12 + Si-28 has been measured down to deep sub-barrier energies, using Si-28 beams from the XTU Tandem accelerator of LNL on thin C-12 targets. Two different set-ups were employed: 1) the fusion-evaporation residues were identified by a detector telescope following an electrostatic beam separator, and 2) coincidences between the gamma-ray array AGATA and segmented silicon detectors DSSD were performed, where the evaporated light charged particles were identified by pulse shape analysis. Fusion cross sections have been obtained in the wide range sigma approximate to 150 mb – 42nb. Coupled-channel (CC) calculations using a Woods-Saxon potential reproduce the data above similar or equal to 0.1 mb. Below that, hindrance shows up and the CC results overestimate the cross sections which get close to the one-dimensional potential tunnelling limit. This suggests that the coupling strengths gradually vanish, as predicted by the adiabatic model. The hindrance threshold follows a recently updated phenomenological systematics.
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Moffat, N., Soto-Oton, J., Rius, G., Cabruja, E., & Pellegrini, G. (2026). A graphene-on-silicon photodetector for low penetrating radiation. Sci Rep, 16(1), 3802–12pp.
Abstract: We introduce an innovative graphene-on-silicon photodiode designed for low penetrating radiation. Its standout feature lies in its remarkably-thin dead layer in the entrance window, setting it apart from existing photodetectors. Conventional photodetectors suffer from sensitivity limitations in the low wavelength or energy, respectively, for light or particles, due to their shallow penetration depth. Most conventional photodiodes employ a junction implant which suffers from recombination of low-penetrating photons/particles within the dead layer. Instead, we utilise the nearly transparent properties of single-layer graphene to create a depletion layer that minimises the dead layer. We combine a single junction ring (highly doped n^++ bias ring) with single-layer graphene. The graphene acts as a field plate, extended over the junction ring and covering the entire entrance window (5x5 mm2 active area), while being electrically isolated by an ultrathin, high K dielectric layer. In operation, the photodiode undergoes depletion upon applying a reverse bias as expected, which primarily occurs within the region beneath the field plate. We conducted Transient Current Technique measurements as the best method to assess the charge collection uniformity of the device. Remarkably, the results reveal a consistent total 100% uniformity across the entire detector area. Nevertheless, while the collection time is position-dependent, increasing as the laser incidence point moves farther away from the bias ring, responsivity measurements show excellent response in both the deep ultra violet and vacuum ultra violet regions with > 100% external quantum efficiency at wavelengths below 150 nm.
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Parveen, S., Bonthu, S., Nath, N., Dey, U. K., & Mehta, P. (2026). Majorana CP violation insights from decaying neutrinos. Nucl. Phys. B, 1023, 117298–20pp.
Abstract: It is well-known that within the standard three flavor neutrino oscillation formalism, the Majorana phases appearing in the neutrino mixing matrix cannot have any effect on neutrino oscillation probabilities thereby evading testability at neutrino oscillation experiments. We consider an effective non-Hermitian Hamiltonian describing three flavor neutrino oscillations with the possibility of neutrino decay and demonstrate that the two Majorana phases can entangle with the off-diagonal decay terms and appear at the level of oscillation probabilities. Using the Cayley-Hamilton theorem, we derive approximate analytical expressions for three flavor neutrino oscillation probabilities in the presence of neutrino decay, taking into account matter effects. In the context of a long baseline neutrino experiment, we then analyse the impact of Majorana phases on the oscillation probabilities for different channels as well as on observables related to CP violation effects in neutrino oscillations. Finally, we discuss the effect of Majorana phases on the parameter degeneracies in the neutrino oscillation framework.
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Olivares Herrador, J., Wroe, L. M., Latina, A., Corsini, R., Wuensch, W., Stapnes, S., et al. (2026). Feasibility of High-Intensity Electron Linacs as Drivers for Compact Neutron Sources. IEEE Trans. Nucl. Sci., 73(1), 2–11.
Abstract: The increasing demand for neutron production facilities is driven both by the growing use of neutrons in a wide range of applications and by the progressive shutdown of major existing sources. These trends highlight the need for efficient and compact alternatives to traditional spallation and reactor-based systems. In this context, the present work investigates the potential of normal-conducting compact electron linacs, operating in the energy range of 20-500 MeV, as drivers for neutron generation. Using detailed G4beamline simulations, the optimal dimensions of a tungsten target are determined, and the resulting neutron emission spectrum is characterized. Two electron linac designs are evaluated as drivers for such a target: the HPCI X-band linac and the CTF3 drive-beam S-band linac. The study demonstrates that neutron source strengths up to 1.5 x 10(15) n/s can be achieved, with energy consumption per neutron produced as low as 5.6 x 10-(10) J/n. These findings suggest that electron-linac-based neutron sources offer a compact and energy-efficient solution suitable for a wide range of applications in research, industry, and medicine.
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Soleti, S. R., Dietz, P., Esteve, R., Garcia-Barrena, J., Herrero,, Lopez, F., et al. (2026). CRYSP: a total-body PET based on cryogenic cesium iodide crystals. Phys. Med. Biol., 71(2), 025001–18pp.
Abstract: Objective. Total body positron emission tomography (TBPET) scanners have the potential to substantially reduce both acquisition time and administered radiation dose, owing to their high sensitivity. However, their widespread clinical adoption is hindered by the high cost of currently available systems. This work explores the use of pure cesium iodide (CsI) monolithic crystals operated at cryogenic temperatures as a cost-effective alternative to rare-earth scintillators for TBPET. Approach. We investigate the performance of pure CsI crystals operated at cryogenic temperatures (similar to 100 K), where they achieve a light yield of approximately 105 photons/MeV. The implications for energy resolution, spatial resolution (including depth-of-interaction (d.o.i.) capability), and timing performance are assessed, with a view toward their integration into a TBPET system. Main results. Cryogenic CsI crystals demonstrated energy resolution below 7% and coincidence time resolution (CTR) at the nanosecond level, despite their relatively slow scintillation decay time. A Monte Carlo simulation of monolithic CsI crystals shows that a millimeter-scale spatial resolution in all three dimensions can be obtained. These characteristics indicate that high-performance PET imaging is achievable with this technology. Significance. A TBPET scanner based on cryogenic CsI monolithic crystals could combine excellent imaging performance with significantly reduced detector costs, enabling broader accessibility and accelerating the adoption of TBPET in both clinical and research settings.
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