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Author Pakarinen, J. et al; Algora, A. doi  openurl
  Title Collectivity in Pb-196, Pb-198 isotopes probed in Coulomb-excitation experiments at REX-ISOLDE Type Journal Article
  Year 2017 Publication Journal of Physics G Abbreviated Journal J. Phys. G  
  Volume 44 Issue 6 Pages 064009 - 10pp  
  Keywords Coulomb excitation; radioactive ion beams; gamma-ray spectroscopy; gamma transitions and level energies  
  Abstract The neutron-deficient Pb-196,Pb-198 isotopes have been studied in Coulomb-excitation experiments employing the Miniball gamma-ray spectrometer and radioactive ion beams from the REX-ISOLDE post-accelerator at CERN. The reduced transition probabilities of the first excited 2(+) states in Pb-196 and Pb-198 nuclei have been measured for the first time. Values of B (E2) = 18.2(-4.1)(+4.8) W. u. and B (E2) = 13.1(-3.5)(+4.9) W. u., were obtained, respectively. The experiment sheds light on the development of collectivity when moving from the regime governed by the generalised seniority scheme to a region, where intruding structures, associated with different deformed shapes, start to come down in energy and approach the spherical ground state.  
  Address [Pakarinen, J.; Grahn, T.; Herzan, A.; Jakobsson, U.; Konki, J.; Peura, P.; Rahkila, P.] Univ Jyvaskyla, Dept Phys, POB 35, FI-40014 Jyvaskyla, Finland, Email: janne.pakarinen@jyu.fi  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0954-3899 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000400875800003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3126  
Permanent link to this record
 

 
Author IDS Collaboration (Lica, R. et al); Morales, A.I. doi  openurl
  Title beta decay studies of n-rich Cs isotopes with the ISOLDE Decay Station Type Journal Article
  Year 2017 Publication Journal of Physics G Abbreviated Journal J. Phys. G  
  Volume 44 Issue 5 Pages 054002 - 14pp  
  Keywords beta decay; exotic nuclei; nuclear deformation; ISOLDE  
  Abstract Neutron-rich Ba isotopes are expected to exhibit octupolar correlations, reaching their maximum in isotopes around mass A = 146. The odd-A neutron-rich members of this isotopic chain show typical patterns related to non-axially symmetric shapes, which are however less marked compared to even-A ones, pointing to a major contribution from vibrations. In the present paper we present results from a recent study focused on Cs148-150 beta-decay performed at the ISOLDE Decay Station equipped with fast-timing detectors. A detailed analysis of the measured decay half-lives and decay scheme of Ba-149 is presented, giving a first insight in the structure of this neutron-rich nucleus.  
  Address [Lica, R.; Borge, M. J. G.; Madurga, M.; Kurcewicz, J.] CERN, CH-1211 Geneva 23, Switzerland, Email: giovanna.benzoni@mi.infn.it  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0954-3899 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000398756400002 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3053  
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Author Tarifeño-Saldivia, A.; Soto, L. doi  openurl
  Title Effects of gas chamber geometry and gas flow on the neutron production in a fast plasma focus neutron source Type Journal Article
  Year 2014 Publication Plasma Physics and Controlled Fusion Abbreviated Journal Plasma Phys. Control. Fusion  
  Volume 56 Issue 12 Pages 125013 - 5pp  
  Keywords pulsed neutron source; repetitive plasma focus; neutron yield measurement; fast plasma focus  
  Abstract This work reports that gas chamber geometry and gas flow management substantially affect the neutron production of a repetitive fast plasma focus. The gas flow rate is the most sensitive parameter. An appropriate design of the gas chamber combined with a suitable flow-rate management can lead to improvements in the neutron production of one order of magnitude working in a fast repetitive mode.  
  Address [Tarifeno-Saldivia, Ariel; Soto, Leopoldo] Comis Chilena Energia Nucl CCHEN, Santiago, Chile, Email: atarisal@gmail.com;  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0741-3335 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000346926300024 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2070  
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Author Blanes, S.; Casas, F.; Oteo, J.A.; Ros, J. doi  openurl
  Title A pedagogical approach to the Magnus expansion Type Journal Article
  Year 2010 Publication European Journal of Physics Abbreviated Journal Eur. J. Phys.  
  Volume 31 Issue 4 Pages 907-918  
  Keywords  
  Abstract Time-dependent perturbation theory as a tool to compute approximate solutions of the Schrodinger equation does not preserve unitarity. Here we present, in a simple way, how the Magnus expansion (also known as exponential perturbation theory) provides such unitary approximate solutions. The purpose is to illustrate the importance and consequences of such a property. We suggest that the Magnus expansion may be introduced to students in advanced courses of quantum mechanics.  
  Address [Blanes, S.] Univ Politecn Valencia, Inst Matemat Multidisciplinar, E-46022 Valencia, Spain, Email: serblaza@imm.upv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0143-0807 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000279393800024 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 259  
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Author Solevi, P.; Muñoz, E.; Solaz, C.; Trovato, M.; Dendooven, P.; Gillam, J.E.; Lacasta, C.; Oliver, J.F.; Rafecas, M.; Torres-Espallardo, I.; Llosa, G. doi  openurl
  Title Performance of MACACO Compton telescope for ion-beam therapy monitoring: first test with proton beams Type Journal Article
  Year 2016 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 61 Issue 14 Pages 5149-5165  
  Keywords ion-beam therapy; range verification; prompt gamma; Compton camera; GATE  
  Abstract In order to exploit the advantages of ion-beam therapy in a clinical setting, delivery verification techniques are necessary to detect deviations from the planned treatment. Efforts are currently oriented towards the development of devices for real-time range monitoring. Among the different detector concepts proposed, Compton cameras are employed to detect prompt gammas and represent a valid candidate for real-time range verification. We present the first on-beam test of MACACO, a Compton telescope (multi-layer Compton camera) based on lanthanum bromide crystals and silicon photo-multipliers. The Compton telescope was first characterized through measurements and Monte Carlo simulations. The detector linearity was measured employing Na-22 and Am-Be sources, obtaining about 10% deviation from linearity at 3.44 MeV. A spectral image reconstruction algorithm was tested on synthetic data. Point-like sources emitting gamma rays with energy between 2 and 7 MeV were reconstructed with 3-5 mm resolution. The two-layer Compton telescope was employed to measure radiation emitted from a beam of 150 MeV protons impinging on a cylindrical PMMA target. Bragg-peak shifts were achieved via adjustment of the PMMA target location and the resulting measurements used during image reconstruction. Reconstructed Bragg peak profiles proved sufficient to observe peak-location differences within 10 mm demonstrating the potential of the MACACO Compton Telescope as a monitoring device for ion-beam therapy.  
  Address [Solevi, Paola; Munoz, Enrique; Solaz, Carles; Trovato, Marco; Gillam, John E.; Lacasta, Carlos; Oliver, Josep F.; Rafecas, Magdalena; Torres-Espallardo, Irene; Llosa, Gabriela] IFIC CSIC UVEG, Inst Fis Corpuscular, Valencia, Spain, Email: paola.solevi@ovgu.de  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000379555300007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2754  
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Author Etxebeste, A.; Barrio, J.; Muñoz, E.; Oliver, J.F.; Solaz, C.; Llosa, G. doi  openurl
  Title 3D position determination in monolithic crystals coupled to SiPMs for PET Type Journal Article
  Year 2016 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 61 Issue 10 Pages 3914-3934  
  Keywords monolithic crystal; silicon photomultiplier; depth of interaction  
  Abstract The interest in using continuous monolithic crystals in positron emission tomography (PET) has grown in the last years. Coupled to silicon photomultipliers (SiPMs), the detector can combine high sensitivity and high resolution, the two main factors to be maximized in a positron emission tomograph. In this work, the position determination capability of a detector comprised of a 12 x 12 x 10 mm(3) LYSO crystal coupled to an 8 x 8-pixel array of SiPMs is evaluated. The 3D interaction position of.-rays is estimated using an analytical model of the light distribution including reflections on the facets of the crystal. Monte Carlo simulations have been performed to evaluate different crystal reflectors and geometries. The method has been characterized and applied to different cases. Intrinsic resolution obtained with the position estimation method used in this work, applied to experimental data, achieves sub-millimetre resolution values. Average resolution over the detector surface for 5 mm thick crystal is similar to 0.9 mm FWHM and similar to 1.2 mm FWHM for 10 mm thick crystal. Depth of interaction resolution is close to 2 mm FWHM in both cases, while the FWTM is similar to 5.3 mm for 5 mm thick crystal and similar to 9.6 mm for 10 mm thick crystal.  
  Address [Etxebeste, Ane; Barrio, John; Munoz, Enrique; Oliver, Josep F.; Solaz, Carles; Llosa, Gabriela] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia, Spain, Email: ane.etxebeste@ific.uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000376792800014 Approved no  
  Is ISI yes International Collaboration no  
  Call Number IFIC @ pastor @ Serial 2708  
Permanent link to this record
 

 
Author Torres-Espallardo, I.; Diblen, F.; Rohling, H.; Solevi, P.; Gillam, J.; Watts, D.; Espana, S.; Vandenberghe, S.; Fiedler, F.; Rafecas, M. doi  openurl
  Title Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring Type Journal Article
  Year 2015 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 60 Issue 9 Pages N187-N208  
  Keywords PET; in-beam; RPC; particle therapy; TOF; range deviation; partial-ring  
  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  
  Address [Torres-Espallardo, I.; Solevi, P.; Gillam, J.; Rafecas, M.] UV, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: irene.torres@uv.es  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000354104700003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2227  
Permanent link to this record
 

 
Author Cabello, J.; Etxebeste, A.; Llosa, G.; Ziegler, S.I. doi  openurl
  Title Simulation study of PET detector limitations using continuous crystals Type Journal Article
  Year 2015 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 60 Issue 9 Pages 3673-3694  
  Keywords continuous crystals; parallax effects; depth of interaction; high resolution; small animal PET  
  Abstract Continuous crystals can potentially obtain better intrinsic detector spatial resolution compared to pixelated crystals, additionally providing depth of interaction (DoI) information from the light distribution. To achieve high performance sophisticated interaction position estimation algorithms are required. There are a number of algorithms in the literature applied to different crystal dimensions and different photodetectors. However, the different crystal properties and photodetector array geometries have an impact on the algorithm performance. In this work we analysed, through Monte Carlo simulations, different combinations of realistic crystals and photodetector parameters to better understand their influence on the interaction position estimation accuracy, with special emphasis on the DoI. We used an interaction position estimation based on an analytical model for the present work. Different photodetector granulation schemes were investigated. The impact of the number of crystal faces readout by photodetectors was studied by simulating scenarios with one and two photodetectors. In addition, crystals with different levels of reflection and aspect ratios (AR) were analysed. Results showed that the impact of photodetector granularity is mainly shown near the edges and specially in the corners of the crystal. The resulting intrinsic spatial resolution near the centre with a 12 x 12 x 10 mm(3) LYSO crystal was 0.7-0.9 mm, while the average spatial resolution calculated on the entire crystal was 0.77 +/- 0.18 mm for all the simulated geometries with one and two photodetectors. Having front and back photodetectors reduced the DoI bias (Euclidean distance between estimated DoI and real DoI) and improved the transversal resolution near the corners. In scenarios with one photodetector, small AR resulted in DoI inaccuracies for absorbed events at the entrance of the crystal. These inaccuracies were slightly reduced either by increasing the AR or reducing the amount of reflected light, and highly mitigated using two photodetectors. Using one photodetector, we obtained a piecewise DoI error model with a DoI resolution of 0.4-0.9 mm for a 1.2 AR crystal, and we observed that including a second photodetector or reducing the amount of reflections reduced the DoI bias but did not significantly improve the DoI resolution. Translating the piecewise DoI error model obtained in this study to image reconstruction we obtained a spatial resolution variability of 0.39 mm using 85% of the FoV, compared to 2.59 mm and 1.87 mm without DoI correction or with a dual layer system, respectively.  
  Address [Cabello, Jorge; Ziegler, Sibylle I.] Tech Univ Munich, Klinikum Rechts Isar, Nukl Med Klin & Poliklin, D-80290 Munich, Germany, Email: jorge.cabello@tum.de  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000354104700019 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2226  
Permanent link to this record
 

 
Author Ortega, P.G.; Torres-Espallardo, I.; Cerutti, F.; Ferrari, A.; Gillam, J.E.; Lacasta, C.; Llosa, G.; Oliver, J.F.; Sala, P.R.; Solevi, P.; Rafecas, M. doi  openurl
  Title Noise evaluation of Compton camera imaging for proton therapy Type Journal Article
  Year 2015 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 60 Issue 5 Pages 1845-1863  
  Keywords proton therapy; Compton camera; Monte Carlo methods; FLUKA; prompt gamma; range verification; MLEM  
  Abstract Compton Cameras emerged as an alternative for real-time dose monitoring techniques for Particle Therapy (PT), based on the detection of prompt-gammas. As a consequence of the Compton scattering process, the gamma origin point can be restricted onto the surface of a cone (Compton cone). Through image reconstruction techniques, the distribution of the gamma emitters can be estimated, using cone-surfaces backprojections of the Compton cones through the image space, along with more sophisticated statistical methods to improve the image quality. To calculate the Compton cone required for image reconstruction, either two interactions, the last being photoelectric absorption, or three scatter interactions are needed. Because of the high energy of the photons in PT the first option might not be adequate, as the photon is not absorbed in general. However, the second option is less efficient. That is the reason to resort to spectral reconstructions, where the incoming. energy is considered as a variable in the reconstruction inverse problem. Jointly with prompt gamma, secondary neutrons and scattered photons, not strongly correlated with the dose map, can also reach the imaging detector and produce false events. These events deteriorate the image quality. Also, high intensity beams can produce particle accumulation in the camera, which lead to an increase of random coincidences, meaning events which gather measurements from different incoming particles. The noise scenario is expected to be different if double or triple events are used, and consequently, the reconstructed images can be affected differently by spurious data. The aim of the present work is to study the effect of false events in the reconstructed image, evaluating their impact in the determination of the beam particle ranges. A simulation study that includes misidentified events (neutrons and random coincidences) in the final image of a Compton Telescope for PT monitoring is presented. The complete chain of detection, from the beam particle entering a phantom to the event classification, is simulated using FLUKA. The range determination is later estimated from the reconstructed image obtained from a two and three-event algorithm based on Maximum Likelihood Expectation Maximization. The neutron background and random coincidences due to a therapeutic-like time structure are analyzed for mono-energetic proton beams. The time structure of the beam is included in the simulations, which will affect the rate of particles entering the detector.  
  Address [Ortega, P. G.; Cerutti, F.; Ferrari, A.] CERN European Org Nucl Res, CH-1217 Meyrin, Switzerland, Email: pgarciao@cern.ch  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000349530700009 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2115  
Permanent link to this record
 

 
Author Solevi, P.; Magrin, G.; Moro, D.; Mayer, R. doi  openurl
  Title Monte Carlo study of microdosimetric diamond detectors Type Journal Article
  Year 2015 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 60 Issue 18 Pages 7069-7083  
  Keywords ion-beam therapy; microdosimetry; diamonds; GATE  
  Abstract Ion-beam therapy provides a high dose conformity and increased radiobiological effectiveness with respect to conventional radiation-therapy. Strict constraints on the maximum uncertainty on the biological weighted dose and consequently on the biological weighting factor require the determination of the radiation quality, defined as the types and energy spectra of the radiation at a specific point. However the experimental determination of radiation quality, in particular for an internal target, is not simple and the features of ion interactions and treatment delivery require dedicated and optimized detectors. Recently chemical vapor deposition (CVD) diamond detectors have been suggested as ion-beam therapy microdosimeters. Diamond detectors can be manufactured with small cross sections and thin shapes, ideal to cope with the high fluence rate. However the sensitive volume of solid state detectors significantly deviates from conventional microdosimeters, with a diameter that can be up to 1000 times the height. This difference requires a redefinition of the concept of sensitive thickness and a deep study of the secondary to primary radiation, of the wall effects and of the impact of the orientation of the detector with respect to the radiation field. The present work intends to study through Monte Carlo simulations the impact of the detector geometry on the determination of radiation quality quantities, in particular on the relative contribution of primary and secondary radiation. The dependence of microdosimetric quantities such as the unrestricted linear energy L and the lineal energy y are investigated for different detector cross sections, by varying the particle type (carbon ions and protons) and its energy.  
  Address [Solevi, Paola; Magrin, Giulio; Mayer, Ramona] EBG MedAustron, A-2700 Wiener Neustadt, Austria, Email: paola.solevi@ovgu.de  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0031-9155 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000361124000004 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2379  
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