toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links (up)
Author AGATA Collaboration (Lalovic, N. et al); Gadea, A.; Domingo-Pardo, C. doi  openurl
  Title Study of isomeric states in Pb-198, Pb-200, Pb-202, Pb-206 and Hg-206 populated in fragmentation reactions Type Journal Article
  Year 2018 Publication Journal of Physics G Abbreviated Journal J. Phys. G  
  Volume 45 Issue 3 Pages 035105 - 27pp  
  Keywords gamma-ray spectroscopy; relativistic projectile fragmentation; direct reactions; isomeric decays; electromagnetic transitions; nuclear shell model  
  Abstract Isomeric states in isotopes in the vicinity of doubly-magic Pb-208 were populated following reactions of a relativistic Pb-208 primary beam impinging on a Be-9 fragmentation target. Secondary beams of Pb-198,Pb-200,Pb-202,Pb-206 and Hg-206 were isotopically separated and implanted in a passive stopper positioned in the focal plane of the GSI Fragment Separator. Delayed gamma rays were detected with the Advanced Gamma Tracking Array (AGATA). Decay schemes were reevaluated and interpreted with shell-model calculations. The momentum-dependent population of isomeric states in the two-nucleon hole nuclei Pb-206/Hg-206 was found to differ from the population of multi neutron-hole isomeric states in Pb-198,Pb-200,Pb-202.  
  Address [Lalovic, N.; Rudolph, D.; Sarmiento, L. G.; Golubev, P.; Fahlander, C.; Gellanki, J.] Lund Univ, Dept Phys, SE-22100 Lund, Sweden, Email: Natasa.Lalovic@nuclear.lu.se  
  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:000424906600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3488  
Permanent link to this record
 

 
Author Rubio, B.; Gelletly, W.; Algora, A.; Nacher, E.; Tain, J.L. doi  openurl
  Title Beta decay studies with total absorption spectroscopy and the Lucrecia spectrometer at ISOLDE Type Journal Article
  Year 2017 Publication Journal of Physics G Abbreviated Journal J. Phys. G  
  Volume 44 Issue 8 Pages 084004 - 25pp  
  Keywords beta decay; strength functions; total absorption gamma spectroscopy; nuclear shapes  
  Abstract Here we present the experimental activities carried out at ISOLDE with the total absorption spectrometer Lucrecia, a large 4 pi scintillator detector designed to absorb a full gamma cascade following beta decay. This spectrometer is designed to measure beta-feeding to excited states without the systematic error called Pandemonium. The set up allows the measurement of decays of very short half life. Experimental results from several campaigns, that focus on the determination of the shapes of beta-decaying nuclei by measuring their beta decay strength distributions as a function of excitation energy in the daughter nucleus, are presented.  
  Address [Rubio, B.; Gelletly, W.; Algora, A.; Tain, J. L.] Univ Valencia, CSIC, IFIC, E-46980 Paterna, Spain, Email: berta.rubio@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 0954-3899 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000404730700001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3192  
Permanent link to this record
 

 
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  
Permanent link to this record
 

 
Author Pujades, M.C.; Granero, D.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Papagiannis, P.; Siebert, F.A. doi  openurl
  Title Air-kerma evaluation at the maze entrance of HDR brachytherapy facilities Type Journal Article
  Year 2014 Publication Journal of Radiological Protection Abbreviated Journal J. Radiol. Prot.  
  Volume 34 Issue 4 Pages 741-753  
  Keywords bunker; shielding; NCRP 151; brachytherapy; Monte Carlo  
  Abstract In the absence of procedures for evaluating the design of brachytherapy (BT) facilities for radiation protection purposes, the methodology used for external beam radiotherapy facilities is often adapted. The purpose of this study is to adapt the NCRP 151 methodology for estimating the air-kerma rate at the door in BT facilities. Such methodology was checked against Monte Carlo (MC) techniques using the code Geant4. Five different facility designs were studied for Ir-192 and Co-60 HDR applications to account for several different bunker layouts. For the estimation of the lead thickness needed at the door, the use of transmission data for the real spectra at the door instead of the ones emitted by Ir-192 and Co-60 will reduce the lead thickness by a factor of five for Ir-192 and ten for Co-60. This will significantly lighten the door and hence simplify construction and operating requirements for all bunkers. The adaptation proposed in this study to estimate the air-kerma rate at the door depends on the complexity of the maze: it provides good results for bunkers with a maze (i.e. similar to those used for linacs for which the NCRP 151 methodology was developed) but fails for less conventional designs. For those facilities, a specific Monte Carlo study is in order for reasons of safety and cost-effectiveness.  
  Address [Pujades, M. C.] Natl Ctr Dosimetry CND, Valencia, Spain, Email: mpuclau@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 0952-4746 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000345895800005 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2031  
Permanent link to this record
 

 
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  
Permanent link to this record
 

 
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 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 Brzezinski, K.; Oliver, J.F.; Gillam, J.; Rafecas, M. doi  openurl
  Title Study of a high-resolution PET system using a Silicon detector probe Type Journal Article
  Year 2014 Publication Physics in Medicine and Biology Abbreviated Journal Phys. Med. Biol.  
  Volume 59 Issue 20 Pages 6117-6140  
  Keywords PET; high-resolution imaging; Si detectors; PET insert  
  Abstract A high-resolution silicon detector probe, in coincidence with a conventional PET scanner, is expected to provide images of higher quality than those achievable using the scanner alone. Spatial resolution should improve due to the finer pixelization of the probe detector, while increased sensitivity in the probe vicinity is expected to decrease noise. A PET-probe prototype is being developed utilizing this principle. The system includes a probe consisting of ten layers of silicon detectors, each a 80 x 52 array of 1 x 1 x 1 mm(3) pixels, to be operated in coincidence with a modern clinical PET scanner. Detailed simulation studies of this system have been performed to assess the effect of the additional probe information on the quality of the reconstructed images. A grid of point sources was simulated to study the contribution of the probe to the system resolution at different locations over the field of view (FOV). A resolution phantom was used to demonstrate the effect on image resolution for two probe positions. A homogeneous source distribution with hot and cold regions was used to demonstrate that the localized improvement in resolution does not come at the expense of the overall quality of the image. Since the improvement is constrained to an area close to the probe, breast imaging is proposed as a potential application for the novel geometry. In this sense, a simplified breast phantom, adjacent to heart and torso compartments, was simulated and the effect of the probe on lesion detectability, through measurements of the local contrast recovery coefficient-to-noise ratio (CNR), was observed. The list-mode ML-EM algorithm was used for image reconstruction in all cases. As expected, the point spread function of the PET-probe system was found to be non-isotropic and vary with position, offering improvement in specific regions. Increase in resolution, of factors of up to 2, was observed in the region close to the probe. Images of the resolution phantom showed visible improvement in resolution when including the probe in the simulations. The image quality study demonstrated that contrast and spill-over ratio in other areas of the FOV were not sacrificed for this enhancement. The CNR study performed on the breast phantom indicates increased lesion detectability provided by the probe.  
  Address [Brzezinski, K.; Oliver, J. F.; Gillam, J.; Rafecas, M.] Univ Valencia, CSIC, Inst Fis Corpuscular, E-46980 Valencia, Spain, Email: brzezinski@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:000343092300011 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 1963  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records:
ific federMinisterio de Ciencia e InnovaciĆ³nAgencia Estatal de Investigaciongva