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Fuster-Martinez, N., Assmann, R. W., Bruce, R., Giovannozzi, M., Hermes, P., Mereghetti, A., et al. (2022). Beam-based aperture measurements with movable collimator jaws as performance booster of the CERN Large Hadron Collider. Eur. Phys. J. Plus, 137(3), 305–20pp.
Abstract: The beam aperture of a particle accelerator defines the clearance available for the circulating beams and is a parameter of paramount importance for the accelerator performance. At the CERN Large Hadron Collider (LHC), the knowledge and control of the available aperture is crucial because the nominal proton beams carry an energy of 362 MJ stored in a superconducting environment. Even a tiny fraction of beam losses could quench the superconducting magnets or cause severe material damage. Furthermore, in a circular collider, the performance in terms of peak luminosity depends to a large extent on the aperture of the inner triplet quadrupoles, which are used to focus the beams at the interaction points. In the LHC, this aperture represents the smallest aperture at top-energy with squeezed beams and determines the maximum potential reach of the peak luminosity. Beam-based aperture measurements in these conditions are difficult and challenging. In this paper, we present different methods that have been developed over the years for precise beam-based aperture measurements in the LHC, highlighting applications and results that contributed to boost the operational LHC performance in Run 1 (2010-2013) and Run 2 (2015-2018)
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Balibrea-Correa, J., Lerendegui-Marco, J., Ladarescu, I., Guerrero, C., Rodriguez-Gonzalez, T., Jimenez-Ramos, M. C., et al. (2022). Hybrid in-beam PET- and Compton prompt-gamma imaging aimed at enhanced proton-range verification. Eur. Phys. J. Plus, 137(11), 1258–18pp.
Abstract: We report on a hybrid in-beam PET and prompt-gamma Compton imaging system aimed at quasi real-time ion-range verification in proton-therapy treatments. Proof-of-concept experiments were carried out at the radiobiology beam line of the CNA cyclotron facility using a set of two synchronous Compton imagers and different target materials. The time structure of the 18 MeV proton beam was shaped with a series of beam-on and beam-off intervals, thereby mimicking a pulsed proton beam on a long time scale. During beam-on intervals, Compton imagingwas performed utilizing the high energy. -rays promptly emitted from the nuclear reactions occurring in the targets. In the course of the beam-off intervals in situ positron-emission tomography was accomplished with the same imagers using the beta+ decay of activated nuclei. The targets used were stacks of different materials covering also various proton ranges and energies. A systematic study on the performance of these two complementary imaging techniques is reported and the experimental results interpreted on the basis ofMonte Carlo calculations. The results demonstrate the possibility to combine both imaging techniques in a concomitant way, where high-efficiency prompt-gamma imaging is complemented with the high spatial accuracy of PET. Empowered by these results we suggest that a pulsed beam with a suitable duty cycle, in conjunction with in situ Compton- and PET-imaging may help to attain complementary information and quasi real-time range monitoring with high accuracy.
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Fanchiotti, H., Garcia Canal, C. A., Traini, M., & Vento, V. (2022). Signatures of excited monopolium. Eur. Phys. J. Plus, 137(12), 1316–19pp.
Abstract: We study electromagnetic properties of particles with magnetic moment and no charge using their behavior when traversing coils and solenoids. These particles via the Faraday-Lenz law create a current whose energy we calculate. We analyze both the case of very long lived, almost stable, particles and those with a finite lifetime. We use this development to study the behavior of monopolium a monopole-antimonopole bound state in its excited states.
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Llosa, G., & Rafecas, M. (2023). Hybrid PET/Compton-camera imaging: an imager for the next generation. Eur. Phys. J. Plus, 138(3), 214–19pp.
Abstract: Compton cameras can offer advantages over gamma cameras for some applications, since they are well suited for multitracer imaging and for imaging high-energy radiotracers, such as those employed in radionuclide therapy. While in conventional clinical settings state-of-the-art Compton cameras cannot compete with well-established methods such as PET and SPECT, there are specific scenarios in which they can constitute an advantageous alternative. The combination of PET and Compton imaging can benefit from the improved resolution and sensitivity of current PET technology and, at the same time, overcome PET limitations in the use of multiple radiotracers. Such a system can provide simultaneous assessment of different radiotracers under identical conditions and reduce errors associated with physical factors that can change between acquisitions. Advances are being made both in instrumentation developments combining PET and Compton cameras for multimodal or three-gamma imaging systems, and in image reconstruction, addressing the challenges imposed by the combination of the two modalities or the new techniques. This review article summarizes the advances made in Compton cameras for medical imaging and their combination with PET.
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Moreira, A. R. P., Belchior, F. M., Maluf, R. V., & Almeida, C. A. S. (2023). Bulk fields localization on thick string-like brane in f(T) gravity. Eur. Phys. J. Plus, 138(8), 730–15pp.
Abstract: This paper aims to investigate the influence of torsion on bulk fields in the codimension two thick brane in f(T) modified teleparallel gravity. It is shown that the brane supports the localization of gauge field zero mode without an extra coupling. However, Kalb-Ramond and fermionic fields require a suitable coupling. Then, it is proposed a geometrical coupling based on results in 5D thick brane in modified teleparallel gravities. The Kalb-Ramond field is coupled to torsion scalar T through a gauge-invariant interaction. For the case of fermionic fields, we study the Dirac fermions and gravitino with a derivative geometrical coupling. For all of the fields, it obtained massive and resonant modes by employing the Schodinger-like approach.
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