Records |
Author |
Brzezinski, K.; Oliver, J.F.; Gillam, J.; Rafecas, M. |
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 |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9155 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000343092300011 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1963 |
Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; March, L.; Marti-Garcia, S.; Mitsou, V.A.; Moles-Valls, R.; Oliver Garcia, E.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Vos, M. |
Title |
A neural network clustering algorithm for the ATLAS silicon pixel detector |
Type |
Journal Article |
Year |
2014 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
Volume |
9 |
Issue |
|
Pages |
P09009 - 34pp |
Keywords |
Particle tracking detectors; Particle tracking detectors (Solid-state detectors) |
Abstract |
A novel technique to identify and split clusters created by multiple charged particles in the ATLAS pixel detector using a set of artificial neural networks is presented. Such merged clusters are a common feature of tracks originating from highly energetic objects, such as jets. Neural networks are trained using Monte Carlo samples produced with a detailed detector simulation. This technique replaces the former clustering approach based on a connected component analysis and charge interpolation. The performance of the neural network splitting technique is quantified using data from proton-proton collisions at the LHC collected by the ATLAS detector in 2011 and from Monte Carlo simulations. This technique reduces the number of clusters shared between tracks in highly energetic jets by up to a factor of three. It also provides more precise position and error estimates of the clusters in both the transverse and longitudinal impact parameter resolution. |
Address |
[Jackson, P.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000343281300046 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1972 |
Permanent link to this record |
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Author |
Ullan, M.; Benitez, V.; Quirion, D.; Zabala, M.; Pellegrini, G.; Lozano, M.; Lacasta, C.; Soldevila, U.; Garcia, C.; Fadeyev, V.; Wortman, J.; DeFilippis, J.; Shumko, M.; Grillo, A.A.; Sadrozinski, H.F.W. |
Title |
Low-resistance strip sensors for beam-loss event protection |
Type |
Journal Article |
Year |
2014 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
Volume |
765 |
Issue |
|
Pages |
252-257 |
Keywords |
Silicon radiation detectors; Strip sensors; Punch through protection; Beam loss; HL-LHC; ATLAS Upgrade |
Abstract |
AC coupled silicon strip sensors can be damaged in case of a beam loss due to the possibility of a large charge accumulation in the bulk, developing very high voltages across the coupling capacitors which can destroy them. Punch-through structures are currently used to avoid this problem helping to evacuate the accumulated charge as large voltages are developing. Nevertheless, previous experiments, performed with laser pulses, have shown that these structures can become ineffective in relatively long strips. The large value of the implant resistance can effectively isolate the “far” end of the strip from the punchthrough structure leading to large voltages. We present here our developments to fabricate lowresistance strip sensors to avoid this problem. The deposition of a conducting material in contact with the implants drastically reduces the strip resistance, assuring the effectiveness of the punch-through structures. First devices have been fabricated with this new technology. Initial results with laser tests show the expected reduction in peak voltages on the low resistivity implants. Other aspects of the sensor performance, including the signal formation, are not affected by the new technology. |
Address |
[Ullan, M.; Benitez, V.; Quirion, D.; Zabala, M.; Pellegrini, G.; Lozano, M.] CSIC, Ctr Nacl Microelect IMB CNM, Barcelona 08193, Spain, Email: Miguel.Ullan@imb-cnm.csic.es |
Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000344621000048 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
2003 |
Permanent link to this record |
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Author |
NEXT Collaboration (Lorca, D. et al); Martin-Albo, J.; Laing, A.; Ferrario, P.; Gomez-Cadenas, J.J.; Alvarez, V.; Carcel, S.; Cervera-Villanueva, A.; Diaz, J.; Liubarsky, I.; Martinez, A.; Monrabal, F.; Monserrate, M.; Muñoz Vidal, J.; Nebot-Guinot, M.; Rodriguez, J.; Serra, L.; Simon, A.; Sorel, M.; Yahlali, N. |
Title |
Characterisation of NEXT-DEMO using xenon K-alpha X-rays |
Type |
Journal Article |
Year |
2014 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
Volume |
9 |
Issue |
|
Pages |
P10007 - 20pp |
Keywords |
Charge transport, multiplication and electroluminescence in rare gases and liquids; Double-beta decay detectors; Time projection chambers |
Abstract |
The NEXT experiment aims to observe the neutrinoless double beta decay of Xe-136 in a high-pressure xenon gas TPC using electroluminescence (EL) to amplify the signal from ionization. Understanding the response of the detector is imperative in achieving a consistent and well understood energy measurement. The abundance of xenon K-shell X-ray emission during data taking has been identified as a multitool for the characterisation of the fundamental parameters of the gas as well as the equalisation of the response of the detector. The NEXT-DEMO prototype is a similar to 1.5 kg volume TPC filled with natural xenon. It employs an array of 19 PMTs as an energy plane and of 256 SiPMs as a tracking plane with the TPC light tube and SiPM surfaces being coated with tetraphenyl butadiene (TPB) which acts as a wavelength shifter for the VUV scintillation light produced by xenon. This paper presents the measurement of the properties of the drift of electrons in the TPC, the effects of the EL production region, and the extraction of position dependent correction constants using K-alpha X-ray deposits. These constants were used to equalise the response of the detector to deposits left by gammas from Na-22. |
Address |
[Lorca, D.; Martin-Albo, J.; Laing, A.; Ferrario, P.; Gomez-Cadenas, J. J.; Alvarez, V.; Carcel, S.; Cervera, A.; Diaz, J.; Liubarsky, I.; Martinez, A.; Monrabal, F.; Monserrate, M.; Munoz Vidal, J.; Nebot-Guinot, M.; Rodriguez, J.; Serra, L.; Simon, A.; Sorel, M.; Yahlali, N.] CSIC, Inst Fis Corpuscular IFIC, Valencia 46980, Spain, Email: david.lorca@ific.uv.es; |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
|
Notes |
WOS:000345858500050 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
2055 |
Permanent link to this record |
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Author |
XENON Collaboration (Aprile, E. et al); Orrigo, S.E.A. |
Title |
Conceptual design and simulation of a water Cherenkov muon veto for the XENON1T experiment |
Type |
Journal Article |
Year |
2014 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
Volume |
9 |
Issue |
|
Pages |
P11006 - 20pp |
Keywords |
Cherenkov detectors; Cherenkov and transition radiation; Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc); Dark Matter detectors (WIMPs, axions, etc.) |
Abstract |
XENON is a dark matter direct detection project, consisting of a time projection chamber (TPC) filled with liquid xenon as detection medium. The construction of the next generation detector, XENON1T, is presently taking place at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It aims at a sensitivity to spin-independent cross sections of 2.10(47) cm(2) for WIMP masses around 50 GeV/c(2), which requires a background reduction by two orders of magnitude compared to XENON100, the current generation detector. An active system that is able to tag muons and muon-induced backgrounds is critical for this goal. A water Cherenkov detector of similar to 10m height and diameter has been therefore developed, equipped with 8 inch photomultipliers and cladded by a reflective foil. We present the design and optimization study for this detector, which has been carried out with a series of Monte Carlo simulations. The muon veto will reach very high detection efficiencies for muons (> 99.5%) and showers of secondary particles from muon interactions in the rock (> 70%). Similar efficiencies will be obtained for XENONnT, the upgrade of XENON1T, which will later improve the WIMP sensitivity by another order of magnitude. With the Cherenkov water shield studied here, the background from muon-induced neutrons in XENON1T is negligible. |
Address |
[Aprile, E.; Contreras, H.; Goetzke, L. W.; Fernandez, A. J. Melgarejo; Messina, M.; Plante, G.; Rizzo, A.] Columbia Univ, Dept Phys, New York, NY 10027 USA, Email: dr.serena.fattori@gmail.com |
Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
|
Medium |
|
Area |
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Expedition |
|
Conference |
|
Notes |
WOS:000345026000020 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
2061 |
Permanent link to this record |