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Barrientos, L., Borja-Lloret, M., Casaña, J. V., Dendooven, P., Garcia Lopez, J. G., Hueso-Gonzalez, F., et al. (2024). Gamma-ray sources imaging and test-beam results with MACACO III Compton camera. Phys. Medica, 117, 103199–10pp.
Abstract: Hadron therapy is a radiotherapy modality which offers a precise energy deposition to the tumors and a dose reduction to healthy tissue as compared to conventional methods. However, methods for real-time monitoring are required to ensure that the radiation dose is deposited on the target. The IRIS group of IFIC-Valencia developed a Compton camera prototype for this purpose, intending to image the Prompt Gammas emitted by the tissue during irradiation. The system detectors are composed of Lanthanum (III) bromide scintillator crystals coupled to silicon photomultipliers. After an initial characterization in the laboratory, in order to assess the system capabilities for future experiments in proton therapy centers, different tests were carried out in two facilities: PARTREC (Groningen, The Netherlands) and the CNA cyclotron (Sevilla, Spain). Characterization studies performed at PARTREC indicated that the detectors linearity was improved with respect to the previous version and an energy resolution of 5.2 % FWHM at 511 keV was achieved. Moreover, the imaging capabilities of the system were evaluated with a line source of 68Ge and a point-like source of 241Am-9Be. Images at 4.439 MeV were obtained from irradiation of a graphite target with an 18 MeV proton beam at CNA, to perform a study of the system potential to detect shifts at different intensities. In this sense, the system was able to distinguish 1 mm variations in the target position at different beam current intensities for measurement times of 1800 and 600 s.
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Baran, J. et al, & Brzezinski, K. (2024). Feasibility of the J-PET to monitor the range of therapeutic proton beams. Phys. Medica, 118, 103301–9pp.
Abstract: Purpose: The aim of this work is to investigate the feasibility of the Jagiellonian Positron Emission Tomography (J -PET) scanner for intra-treatment proton beam range monitoring. Methods: The Monte Carlo simulation studies with GATE and PET image reconstruction with CASToR were performed in order to compare six J -PET scanner geometries. We simulated proton irradiation of a PMMA phantom with a Single Pencil Beam (SPB) and Spread -Out Bragg Peak (SOBP) of various ranges. The sensitivity and precision of each scanner were calculated, and considering the setup's cost-effectiveness, we indicated potentially optimal geometries for the J -PET scanner prototype dedicated to the proton beam range assessment. Results: The investigations indicate that the double -layer cylindrical and triple -layer double -head configurations are the most promising for clinical application. We found that the scanner sensitivity is of the order of 10-5 coincidences per primary proton, while the precision of the range assessment for both SPB and SOBP irradiation plans was found below 1 mm. Among the scanners with the same number of detector modules, the best results are found for the triple -layer dual -head geometry. The results indicate that the double -layer cylindrical and triple -layer double -head configurations are the most promising for the clinical application, Conclusions: We performed simulation studies demonstrating that the feasibility of the J -PET detector for PET -based proton beam therapy range monitoring is possible with reasonable sensitivity and precision enabling its pre -clinical tests in the clinical proton therapy environment. Considering the sensitivity, precision and cost-effectiveness, the double -layer cylindrical and triple -layer dual -head J -PET geometry configurations seem promising for future clinical application.
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Angles-Castillo, A., Perez, A., & Roldan, E. (2024). Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum. New J. Phys., 26(2), 023004–16pp.
Abstract: We propose a nonlinear quantum walk model inspired in a photonic implementation in which the polarization state of the light field plays the role of the coin-qubit. In particular, we take profit of the nonlinear polarization rotation occurring in optical media with Kerr nonlinearity, which allows to implement a nonlinear coin operator, one that depends on the state of the coin-qubit. We consider the space-time continuum limit of the evolution equation, which takes the form of a nonlinear Dirac equation. The analysis of this continuum limit allows us to gain some insight into the existence of different solitonic structures, such as bright and dark solitons. We illustrate several properties of these solitons with numerical calculations, including the effect on them of an additional phase simulating an external electric field.
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Sorelli, G., Gessner, M., Treps, N., & Walschaers, M. (2024). Gaussian quantum metrology for mode-encoded parameters. New J. Phys., 26(7), 073022–23pp.
Abstract: Quantum optical metrology aims to identify ultimate sensitivity bounds for the estimation of parameters encoded into quantum states of the electromagnetic field. In many practical applications, including imaging, microscopy, and remote sensing, the parameter of interest is not only encoded in the quantum state of the field, but also in its spatio-temporal distribution, i.e. in its mode structure. In this mode-encoded parameter estimation setting, we derive an analytical expression for the quantum Fisher information valid for arbitrary multimode Gaussian fields. To illustrate the power of our approach, we apply our results to the estimation of the transverse displacement of a beam and to the temporal separation between two pulses. For these examples, we show how the estimation sensitivity can be enhanced by adding squeezing into specific modes.
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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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