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Gomez-Cadenas, J. J., Benlloch-Rodriguez, J. M., & Ferrario, P. (2016). Application of scintillating properties of liquid xenon and silicon photomultiplier technology to medical imaging. Spectroc. Acta Pt. B, 118, 6–13.
Abstract: We describe a new positron emission time-of-flight apparatus using liquid xenon. The detector is based in a liquid xenon scintillating cell. The cell shape and dimensions can be optimized depending on the intended application. In its simplest form, the liquid xenon scintillating cell is a box in which two faces are covered by silicon photomultipliers and the others by a reflecting material such as Teflon. It is a compact, homogenous and highly efficient detector which shares many of the desirable properties of monolithic crystals, with the added advantage of high yield and fast scintillation offered by liquid xenon. Our initial studies suggest that good energy and spatial resolution comparable with that achieved by lutetium oxyorthosilicate crystals can be obtained with a detector based in liquid xenon scintillating cells. In addition, the system can potentially achieve an excellent coincidence resolving time of better than 100 ps.
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Torres-Espallardo, I., Diblen, F., Rohling, H., Solevi, P., Gillam, J., Watts, D., et al. (2015). Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring. Phys. Med. Biol., 60(9), N187–N208.
Abstract: Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scannerbeam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options. based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadron
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n_TOF Collaboration(Guerrero, C. et al), Domingo-Pardo, C., & Tain, J. L. (2011). Study of Photon Strength Function of Actinides: the Case of (235)U, (238)Np and (241)Pu. J. Korean Phys. Soc., 59(2), 1510–1513.
Abstract: The decay from excited levels in medium and heavy nuclei can be described in a statistical approach by means of Photon Strength Functions and Level Density distributions. The study of electromagnetic cascades following neutron capture based on the use of high efficiency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF of actinides, in particular (235)U, (238)Np and (241)Pu. Our study includes the search for resonance structures in the PSF below S(n) and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature.
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n_TOF Collaboration(Chiaveri, E. et al), Giubrone, G., & Tain, J. L. (2011). Past, Present and Future of the n_TOF Facility at CERN. J. Korean Phys. Soc., 59(2), 1620–1623.
Abstract: The nTOF spallation neutron facility is operating at CERN since 2001. Neutrons are produced with a very wide energy range, from thermal up to 1 GeV and with a very high instantaneous flux (10(5)n/cm(2)/pulse at 200 m from target) thanks to the high intensity (7 x 10(12) protons/pulse) and low repetition rate of the Proton Synchrotron (PS) which is delivering protons to a lead spallation target. The experimental area is located at 200 m from the target, resulting in a very good energy resolution and beam quality thanks to the adoption of an optimal collimation system. At the end of 2008 the nTOF facility has resumed operation after a halt of 3 years due to technical issues. This contribution will outline the main physics results obtained by the facility since its inception in 1999, and show the importance of the measured nuclear data in the field of Nuclear Astrophysics and Nuclear Technology. Then it will present the future perspectives of the facility, aiming mainly in the direction of measuring highly radioactive samples, for which the facility has unique capabilities, with a lower background.
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n_TOF Collaboration(Guerrero, C. et al), Giubrone, G., & Tain, J. L. (2011). Characterization of the New n_TOF Neutron Beam: Fluence, Profile and Resolution. J. Korean Phys. Soc., 59(2), 1624–1627.
Abstract: After a halt of four years, the nTOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and efficient cooling. The first measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated fission chambers, the nTOF Silicon Monitor, a MicroMegas detector with (10)B and (235)U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron fluence. The spatial profile of the beam has been studied with a specially designed “X-Y” MicroMegas which provided a 2D image of the beam as a function of neutron energy. Both properties have been compared with simulations performed. with the FLUKA code. The characterization of the resolution function is based on results from simulations which have been verified by the study of narrow capture resonances. of (56)Fe, which were measured as part of a new campaign of (n,gamma) measurements on Fe and Ni isotopes.
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