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Author Gammaldi, V.; Zaldivar, B.; Sanchez-Conde, M.A.; Coronado-Blazquez, J.
Title A search for dark matter among Fermi-LAT unidentified sources with systematic features in machine learning Type Journal Article
Year 2023 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal Mon. Not. Roy. Astron. Soc.
Volume 520 Issue 1 Pages 1348-1361
Keywords astroparticle physics – methods; data analysis – methods; observational – methods; statistical – dark matter – gamma-rays; general
Abstract Around one-third of the point-like sources in the Fermi-LAT catalogues remain as unidentified sources (unIDs) today. Indeed, these unIDs lack a clear, univocal association with a known astrophysical source. If dark matter (DM) is composed of weakly interacting massive particles (WIMPs), there is the exciting possibility that some of these unIDs may actually be DM sources, emitting gamma-rays from WIMPs annihilation. We propose a new approach to solve the standard, machine learning (ML) binary classification problem of disentangling prospective DM sources (simulated data) from astrophysical sources (observed data) among the unIDs of the 4FGL Fermi-LAT catalogue. We artificially build two systematic features for the DM data which are originally inherent to observed data: the detection significance and the uncertainty on the spectral curvature. We do it by sampling from the observed population of unIDs, assuming that the DM distributions would, if any, follow the latter. We consider different ML models: Logistic Regression, Neural Network (NN), Naive Bayes, and Gaussian Process, out of which the best, in terms of classification accuracy, is the NN, achieving around 93 . 3 per cent +/- 0 . 7 per cent performance. Other ML evaluation parameters, such as the True Ne gativ e and True Positive rates, are discussed in our work. Applying the NN to the unIDs sample, we find that the de generac y between some astrophysical and DM sources can be partially solved within this methodology. None the less, we conclude that there are no DM source candidates among the pool of 4FGL Fermi-LAT unIDs.
Address [Gammaldi, V; Sanchez-Conde, M. A.; Coronado-Blazquez, J.] Univ Autonoma Madrid, Departamentode Fis Teor, E-28049 Madrid, Spain, Email: viviana.gammaldi@uam.es;
Corporate Author Thesis
Publisher Oxford Univ Press Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0035-8711 ISBN Medium
Area Expedition Conference
Notes WOS:000937053400014 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ pastor @ Serial 5489
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Author Pierre Auger Collaboration (Abreu, P. et al); Pastor, S.
Title Large-scale distribution of arrival directions of cosmic rays detected above 10^18 eV at the Pierre Auger Observatory Type Journal Article
Year 2012 Publication Astrophysical Journal Supplement Series Abbreviated Journal Astrophys. J. Suppl. Ser.
Volume 203 Issue 2 Pages 34 - 20pp
Keywords astroparticle physics; cosmic rays
Abstract A thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10(18) eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10(18) eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10(18) eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.
Address [Abreu, P.; Andringa, S.; Assis, P.; Brogueira, P.; Cazon, L.; Conceicao, R.; Diogo, F.; Espadanal, J.; Goncalves, P.; Pimenta, M.; Santo, C. E.; Santos, E.; Tome, B.] Univ Tecn Lisboa, LIP, Lisbon, Portugal
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 (up) 0067-0049 ISBN Medium
Area Expedition Conference
Notes WOS:000312100500018 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1272
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Author Assam, I.; Vijande, J.; Ballester, F.; Perez-Calatayud, J.; Poppe, B.; Siebert, F.A.
Title Evaluation of dosimetric effects of metallic artifact reduction and tissue assignment on Monte Carlo dose calculations for I-125 prostate implants Type Journal Article
Year 2022 Publication Medical Physics Abbreviated Journal Med. Phys.
Volume 49 Issue Pages 6195-6208
Keywords metallic artifact reduction; Monte Carlo dosimetry; post-implant CT; prostate brachytherapy; tissue assignment schemes; voxelized virtual patient model
Abstract Purpose Monte Carlo (MC) simulation studies, aimed at evaluating the magnitude of tissue heterogeneity in I-125 prostate permanent seed implant brachytherapy (BT), customarily use clinical post-implant CT images to generate a virtual representation of a realistic patient model (virtual patient model). Metallic artifact reduction (MAR) techniques and tissue assignment schemes (TAS) are implemented on the post-implant CT images to mollify metallic artifacts due to BT seeds and to assign tissue types to the voxels corresponding to the bright seed spots and streaking artifacts, respectively. The objective of this study is to assess the combined influence of MAR and TAS on MC absorbed dose calculations in post-implant CT-based phantoms. The virtual patient models used for I-125 prostate implant MC absorbed dose calculations in this study are derived from the CT images of an external radiotherapy prostate patient without BT seeds and prostatic calcifications, thus averting the need to implement MAR and TAS. Methods The geometry of the IsoSeed I25.S17plus source is validated by comparing the MC calculated results of the TG-43 parameters for the line source approximation with the TG-43U1S2 consensus data. Four MC absorbed dose calculations are performed in two virtual patient models using the egs_brachy MC code: (1) TG-43-based D-w,w-TG(43), (2) D-w,D-w-MBDC that accounts for interseed scattering and attenuation (ISA), (3) D-m,D-m that examines ISA and tissue heterogeneity by scoring absorbed dose in tissue, and (4) D-w,D-m that unlike D-m,D-m scores absorbed dose in water. The MC absorbed doses (1) and (2) are simulated in a TG-43 patient phantom derived by assigning the densities of every voxel to 1.00 g cm(-3) (water), whereas MC absorbed doses (3) and (4) are scored in the TG-186 patient phantom generated by mapping the mass density of each voxel to tissue according to a CT calibration curve. The MC absorbed doses calculated in this study are compared with VariSeed v8.0 calculated absorbed doses. To evaluate the dosimetric effect of MAR and TAS, the MC absorbed doses of this work (independent of MAR and TAS) are compared to the MC absorbed doses of different I-125 source models from previous studies that were calculated with different MC codes using post-implant CT-based phantoms generated by implementing MAR and TAS on post-implant CT images. Results The very good agreement of TG-43 parameters of this study and the published consensus data within 3% validates the geometry of the IsoSeed I25.S17plus source. For the clinical studies, the TG-43-based calculations show a D-90 overestimation of more than 4% compared to the more realistic MC methods due to ISA and tissue composition. The results of this work generally show few discrepancies with the post-implant CT-based dosimetry studies with respect to the D-90 absorbed dose metric parameter. These discrepancies are mainly Type B uncertainties due to the different I-125 source models and MC codes. Conclusions The implementation of MAR and TAS on post-implant CT images have no dosimetric effect on the I-125 prostate MC absorbed dose calculation in post-implant CT-based phantoms.
Address [Assam, Isong; Siebert, Frank-Andre] UKSH, Clin Radiotherapy Radiooncol, Campus Kiel, Kiel, Germany, Email: Isong.Assam@uksh.de
Corporate Author Thesis
Publisher Wiley Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0094-2405 ISBN Medium
Area Expedition Conference
Notes WOS:000835807200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5321
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Author Mendez, V.; Amoros, G.; Garcia, F.; Salt, J.
Title Emergent algorithms for replica location and selection in data grid Type Journal Article
Year 2010 Publication Future Generation Computer Systems Abbreviated Journal Futur. Gener. Comp. Syst.
Volume 26 Issue 7 Pages 934-946
Keywords Grid computing; Algorithms; Optimization methods; Artificial intelligence
Abstract Grid infrastructures for e-Science projects are growing in magnitude terms. Improvements in data Grid replication algorithms may be critical in many of these infrastructures. This paper shows a decentralized replica optimization service, providing a general Emergent Artificial Intelligence (EAI) algorithm for the problem definition. Our aim is to set up a theoretical framework for emergent heuristics in Grid environments. Further, we describe two EAI approaches, the Particle Swarm Optimization PSO-Grid Multiswarm Federation and the Ant Colony Optimization ACO-Grid Asynchronous Colonies Optimization replica optimization algorithms, with some examples. We also present extended results with best performance and scalability features for PSO-Grid Multiswarrn Federation.
Address [Mendez Munoz, Victor; Amoros Vicente, Gabriel; Salt Cairols, Jose] CSIC, Grid & E Sci Grp, Inst Fis Corpuscular IFIC, Mixed Inst, E-46071 Valencia, Spain, Email: vmendez@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0167-739x ISBN Medium
Area Expedition Conference
Notes ISI:000279804200004 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 411
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Author Amaldi, U.; Bonomi, R.; Braccini, S.; Crescenti, M.; Degiovanni, A.; Garlasche, M.; Garonna, A.; Magrin, G.; Mellace, C.; Pearce, P.; Pitta, G.; Puggioni, P.; Rosso, E.; Verdu-Andres, S.; Wegner, R.; Weiss, M.; Zennaro, R.
Title Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs Type Journal Article
Year 2010 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 620 Issue 2-3 Pages 563-577
Keywords Medical accelerators; Linac; Cyclotron; Synchrotron; Cyclinac; Radiation oncology; Hadrontherapy; Particle therapy; Proton therapy; Carbon ion therapy; Dose delivery
Abstract Hadrontherapy with protons and carbon ions is a fast developing methodology in radiation oncology. The accelerators used and planned for this purpose are reviewed starting from the cyclotrons used in the thirties. As discussed in the first part of this paper, normal and superconducting cyclotrons are still employed, together with synchrotrons, for proton therapy while for carbon ion therapy synchrotrons have been till now the only option. The latest developments concern a superconducting cyclotron for carbon ion therapy, fast-cycling high frequency linacs and 'single room' proton therapy facilities. These issues are discussed in the second part of the paper by underlining the present challenges, in particular the treatment of moving organs.
Address [Amaldi, U.; Bonomi, R.; Braccini, S.; Crescenti, M.; Degiovanni, A.; Garlasche, M.; Garonna, A.; Magrin, G.; Mellace, C.; Pearce, P.; Pitta, G.; Puggioni, P.; Rosso, E.; Andres, S. Verdu; Wegner, R.; Weiss, M.; Zennaro, R.] TERA Fdn, Novara, Italy, Email: Saverio.Braccini@cern.ch
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes ISI:000280601700058 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 401
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Author ANTARES Collaboration (Ageron, M. et al); Aguilar, J.A.; Bigongiari, C.; Carmona, E.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Real, D.; Roca, V.; Salesa, F.; Toscano, S.; Urbano, F.; Yepes, H.; Zornoza, J.D.; Zuñiga, J.
Title ANTARES: The first undersea neutrino telescope Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 656 Issue 1 Pages 11-38
Keywords Neutrino; Astroparticle; Neutrino astronomy; Deep sea detector; Marine technology; DWDM; Photomultiplier tube; Submarine cable; Wet mateable connector
Abstract The ANTARES Neutrino Telescope was completed in May 2008 and is the first operational Neutrino Telescope in the Mediterranean Sea. The main purpose of the detector is to perform neutrino astronomy and the apparatus also offers facilities for marine and Earth sciences. This paper describes the design, the construction and the installation of the telescope in the deep sea, offshore from Toulon in France. An illustration of the detector performance is given.
Address [Barbarito, E; Cassano, B; Ceres, A; Circella, M; Fiorello, C; Mongelli, M; Montaruli, T; Ruppi, M] Ist Nazl Fis Nucl, Sez Bari, I-70126 Bari, Italy, Email: Marco.Circella@ba.infn.it
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000296129100003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 785
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Author Affolder, A. et al; Garcia, C.; Lacasta, C.; Marco, R.; Marti-Garcia, S.; Miñano, M.; Soldevila, U.
Title Silicon detectors for the sLHC Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 658 Issue 1 Pages 11-16
Keywords Silicon particle detectors; Radiation damage; Irradiation; Charge collection efficiency
Abstract In current particle physics experiments, silicon strip detectors are widely used as part of the inner tracking layers. A foreseeable large-scale application for such detectors consists of the luminosity upgrade of the Large Hadron Collider (LHC), the super-LHC or sLHC, where silicon detectors with extreme radiation hardness are required. The mission statement of the CERN RD50 Collaboration is the development of radiation-hard semiconductor devices for very high luminosity colliders. As a consequence, the aim of the R&D programme presented in this article is to develop silicon particle detectors able to operate at sLHC conditions. Research has progressed in different areas, such as defect characterisation, defect engineering and full detector systems. Recent results from these areas will be presented. This includes in particular an improved understanding of the macroscopic changes of the effective doping concentration based on identification of the individual microscopic defects, results from irradiation with a mix of different particle types as expected for the sLHC, and the observation of charge multiplication effects in heavily irradiated detectors at very high bias voltages.
Address [Barber, T.; Breindl, M.; Driewer, A.; Koehler, M.; Kuehn, S.; Parzefall, U.; Preiss, J.; Walz, M.; Wiik, L.] Univ Freiburg, Inst Phys, D-79104 Freiburg, Germany, Email: Ulrich.Parzefall@physik.uni-freiburg.de
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000297783300004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 836
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Author Mengoni, D.; Duenas, J.A.; Assie, M.; Boiano, C.; John, P.R.; Aliaga, R.J.; Beaumel, D.; Capra, S.; Gadea, A.; Gonzales, V.; Gottardo, A.; Grassi, L.; Herrero-Bosch, V.; Houdy, T.; Martel, I.; Parkar, V.V.; Perez-Vidal, R.M.; Pullia, A.; Sanchis, E.; Triossi, A.; Valiente-Dobon, J.J.
Title Digital pulse-shape analysis with a TRACE early silicon prototype Type Journal Article
Year 2014 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 764 Issue Pages 241-246
Keywords Silicon detector; Light-charged particles; Digital pulse shape analysis; Particle identification; Gamma-ray spectroscopy
Abstract A highly segmented silicon-pad detector prototype has been tested to explore the performance of the digital pulse shape analysis in the discrimination of the particles reaching the silicon detector. For the first time a 200 tun thin silicon detector, grown using an ordinary floating zone technique, has been shown to exhibit a level discrimination thanks to the fine segmentation. Light-charged particles down to few MeV have been separated, including their punch-through. A coaxial HPGe detector in time coincidence has further confirmed the quality of the particle discrimination.
Address [Mengoni, D.; John, P. R.; Grassi, L.] Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000341987000030 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1929
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Author Brook, N.H.; Castillo Garcia, L.; Conneely, T.M.; Cussans, D.; van Dijk, M.W.U.; Fohl, K.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Hancock, T.H.; Harnew, N.; Lapington, J.; Milnes, J.; Piedigrossi, D.; Rademacker, J.; Ros Garcia, A.
Title Testbeam studies of a TORCH prototype detector Type Journal Article
Year 2018 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 908 Issue Pages 256-268
Keywords Cherenkov radiation; Particle identification; TORCH; MCP-PMT
Abstract TORCH is a novel time-of-flight detector that has been developed to provide charged-particle identification between 2 and 10 GeV/c momentum. TORCH combines arrival times from multiple Cherenkov photons produced within a 10 mm-thick quartz radiator plate, to achieve a 15 ps time-of-flight resolution per incident particle. A customised Micro-Channel Plate photomultiplier tube (MCP-PMT) and associated readout system utilises an innovative charge-sharing technique between adjacent pixels to obtain the necessary 70 ps time resolution of each Cherenkov photon. A five-year R&D programme has been undertaken, culminating in the construction of a small-scale prototype TORCH module. In testbeams at CERN, this prototype operated successfully with customised electronics and readout system. A full analysis chain has been developed to reconstruct the data and to calibrate the detector. Results are compared to those using a commercial Planacon MCP-PMT, and single photon resolutions approaching 80 ps have been achieved. The photon counting efficiency was found to be in reasonable agreement with a GEANT4 Monte Carlo simulation of the detector. The small-scale demonstrator is a precursor to a full-scale TORCH module (with a radiator plate of 660 x 1250 x 10 mm(3)), which is currently under construction.
Address [Brook, N. H.; Cussans, D.; Garcia, A. Ros] Univ Bristol, HH Wills Phys Lab, Tyndall Ave, Bristol BS8 1TL, Avon, England, Email: mvandijk@cern.ch
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000446864600033 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3760
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Author Capra, S.; Mengoni, D.; Dueñas, J.A.; John, P.R.; Gadea, A.; Aliaga, R.J.; Dormard, J.J.; Assie, M.; Pullia, A.
Title Performance of the new integrated front-end electronics of the TRACE array commissioned with an early silicon detector prototype Type Journal Article
Year 2019 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 935 Issue Pages 178-184
Keywords ASIC; Charge-sensitive preamplifier; Low-noise applications; Particle spectrometry; Dead time; Silicon detector
Abstract The spectroscopic performances of the new integrated ASIC (Application-Specific Integrated Circuit) preamplifiers for highly segmented silicon detectors have been evaluated with an early silicon detector prototype of the TRacking Array for light Charged Ejectiles (TRACE). The ASICS were mounted on a custom-designed PCB (Printed Circuit Board) and the detector plugged on it. Energy resolution tests, performed on the same detector before and after irradiation, yielded a resolution of 21 keV and 33 keV FWHM respectively. The output signals were acquired with an array of commercial 100-MHz 14-bit digitizers. The preamplifier chip is equipped with an innovative Fast-Reset device that has two functions: it reduces dramatically the dead time of the preamplifier in case of saturation (from milliseconds to microseconds) and extends the spectroscopic dynamic range of the preamplifier by more than one order of magnitude. Other key points of the device are the low noise and the wide bandwidth.
Address [Capra, S.; Pullia, A.] Univ Milan, Dipartimento Fis, Via Celoria 16, IT-20133 Milan, Italy, Email: stefano.capra@unimi.it
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (up) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000470063800026 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4042
Permanent link to this record