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Author |
Studen, A.; Chesi, E.; Cindro, V.; Clinthorne, N.H.; Cochran, E.; Grosicar, B.; Honscheid, K.; Kagan, H.; Lacasta, C.; Llosa, G.; Linhart, V.; Mikuz, M.; Stankova, V.; Weilhammer, P.; Zontar, D. |
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Title  |
A silicon PET probe |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
648 |
Issue |
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Pages |
S255-S258 |
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Keywords |
PET; Silicon detectors |
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Abstract |
PET scanners with high spatial resolution offer a great potential in improving diagnosis, therapy monitoring and treatment validation for several severe diseases. One way to improve resolution of a PET scanner is to extend a conventional PET ring with a small probe with excellent spatial resolution. The probe is intended to be placed close to the area of interest. The coincidences of interactions within the probe and the external ring provide a subset of data which combined with data from external ring, greatly improve resolution in the area viewed by the probe. Our collaboration is developing a prototype of a PET probe, composed of high-resolution silicon pad detectors. The detectors are 1 mm thick, measuring 40 by 26 mm(2), and several such sensors are envisaged to either compensate for low stopping power of silicon or increase the area covered by the probe. The sensors are segmented into 1 mm(3) cubic voxels, giving 1040 readout pads per sensor. A module is composed of two sensors placed in a back-to-back configuration, allowing for stacking fraction of up to 70% within a module. The pads are coupled to a set of 16 ASICs (VaTaGP7.1 by IDEAS) per module and read out through a custom designed data acquisition board, allowing for trigger and data interfacing with the external ring. This paper presents an overview of probe requirements and expected performance parameters. It will focus on the characteristics of the silicon modules and their impact on overall probe performance, including spatial resolution, energy resolution and timing resolution. We will show that 1 mm(3) voxels will significantly extend the spatial resolution of conventional PET rings, and that broadening of timing resolution related to varying depth of photon interactions can be compensated to match the timing resolution of the external ring. The initial test results of the probe will also be presented. |
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Address |
[Studen, A.; Cindro, V.; Grosicar, B.; Mikuz, M.; Zontar, D.] Jozef Stefan Inst, Ljubljana, Slovenia, Email: andrej.studen@ijs.si |
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Publisher |
Elsevier Science Bv |
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English |
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ISSN |
0168-9002 |
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Conference |
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Notes |
WOS:000305376900063 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1070 |
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Author |
DELPHI Collaboration (Abdallah, J. et al); Costa, M.J.; Ferrer, A.; Fuster, J.; Garcia, C.; Oyanguren, A.; Perepelitsa, V.; Salt, J.; Tortosa, P. |
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Title |
A study of the b-quark fragmentation function with the DELPHI detector at LEP I and an averaged distribution obtained at the Z Pole |
Type |
Journal Article |
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Year |
2011 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
71 |
Issue |
2 |
Pages |
1557 - 29pp |
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Keywords |
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Abstract |
The nature of b-quark jet hadronisation has been investigated using data taken at the Z peak by the DELPHI detector at LEP. Two complementary methods are used to reconstruct the energy of weakly decaying b-hadrons, E-B(weak). The average value of x(B)(weak) = E-B(weak)/E-beam is measured to be 0.699 +/- 0.011. The resulting x(B)(weak) distribution is then analysed in the framework of two choices for the perturbative contribution (parton shower and Next to Leading Log QCD calculation) in order to extract measurements of the non-perturbative contribution to be used in studies of b-hadron production in other experimental environments than LEP. In the parton shower framework, data favour the Lund model ansatz and corresponding values of its parameters have been determined within PYTHIA 6.156 from DELPHI data: a = 1.84(-0.21)(+0.23) and b = 0.642(-0.063)(+0.073) GeV-2, with a correlation factor rho = 92.2%. Combining the data on the b-quark fragmentation distributions with those obtained at the Z peak by ALEPH, OPAL and SLD, the average value of x(B)(weak) is found to be 0.7092 +/- 0.0025 and the non-perturbative fragmentation component is extracted. Using the combined distribution, a better determination of the Lund parameters is also obtained: a = 1.48(-0.10)(+0.11) and b = 0.509(-0.023)(+0.024) GeV-2, with a correlation factor rho = 92.6%. |
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Address |
[Lamsa, J.] Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA, Email: timmerma@mail.cern.ch |
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Publisher |
Springer |
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English |
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Edition |
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ISSN |
1434-6044 |
ISBN |
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Conference |
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Notes |
ISI:000291694100016 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
655 |
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Author |
ANTARES Collaboration (van Haren, H. et al); Aguilar, J.A.; Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
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Title |
Acoustic and optical variations during rapid downward motion episodes in the deep north-western Mediterranean Sea |
Type |
Journal Article |
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Year |
2011 |
Publication |
Deep-Sea Research Part I-Oceanographic Research Papers |
Abbreviated Journal |
Deep-Sea Res. Part I-Oceanogr. Res. Pap. |
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Volume |
58 |
Issue |
8 |
Pages |
875-884 |
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Keywords |
Acoustic ADCP observations; Optical photo-multiplier observations; Deep Mediteranean; ANTARES neutrino telescope; Episodic downward current; Bioluminescence; Dense water formation; Northern boundary current |
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Abstract |
An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s(-1) in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s(-1). These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep dense-water formation occurred in the Ligurian subbasin, thus providing a possible explanation for these observations. However, the 10-20 days quasi-periodic episodes of high levels of acoustic reflection, light and large vertical currents continuing into the summer are not direct evidence of this process. It is hypothesized that the main process allowing for suspended material to be moved vertically later in the year is local advection, linked with topographic boundary current instabilities along the rim of the 'Northern Current'. |
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Address |
[van Haren, H] Royal Netherlands Inst Sea Res NIOZ, NL-1797 SZ T Horntje, Texel, Netherlands, Email: hans.van.haren@nioz.nl |
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Publisher |
Pergamon-Elsevier Science Ltd |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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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 |
0967-0637 |
ISBN |
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Conference |
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Notes |
WOS:000295115400006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
770 |
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Author |
Mayoral, C.; Recati, A.; Fabbri, A.; Parentani, R.; Balbinot, R.; Carusotto, I. |
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Title |
Acoustic white holes in flowing atomic Bose-Einstein condensates |
Type |
Journal Article |
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Year |
2011 |
Publication |
New Journal of Physics |
Abbreviated Journal |
New J. Phys. |
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Volume |
13 |
Issue |
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Pages |
025007 - 29pp |
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Keywords |
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Abstract |
We study acoustic white holes in a steadily flowing atomic Bose-Einstein condensate. A white hole configuration is obtained when the flow velocity goes from a super-sonic value in the upstream region to a sub-sonic one in the downstream region. The scattering of phonon wavepackets on a white hole horizon is numerically studied in terms of the Gross-Pitaevskii equation of mean-field theory: dynamical stability of the acoustic white hole is found, as well as a signature of a nonlinear back-action of the incident phonon wavepacket onto the horizon. The correlation pattern of density fluctuations is numerically studied by means of the truncated-Wigner method, which includes quantum fluctuations. Signatures of the white hole radiation of correlated phonon pairs by the horizon are characterized; analogies and differences with Hawking radiation from acoustic black holes are discussed. In particular, a short wavelength feature is identified in the density correlation function, whose amplitude steadily grows in time since the formation of the horizon. The numerical observations are quantitatively interpreted by means of an analytical Bogoliubov theory of quantum fluctuations for a white hole configuration within the step-like horizon approximation. |
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Address |
[Recati, Alessio; Carusotto, Iacopo] Univ Trent, INO CNR BEC Ctr, I-38123 Povo, Italy, Email: carusott@science.unitn.it |
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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 |
1367-2630 |
ISBN |
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Conference |
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Notes |
ISI:000287855400003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
556 |
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Author |
Morisi, S.; Peinado, E. |
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Title |
Admixture of quasi-Dirac and Majorana neutrinos with tri-bimaximal mixing |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
701 |
Issue |
4 |
Pages |
451-457 |
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Keywords |
Neutrinoless double beta decay; Neutrino masses and mixings; Flavor symmetries; Tri-bimaximal mixing; Neutrino hierarchy; Discrete symmetries |
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Abstract |
We propose a realization of the so-called bimodal/schizophrenic model proposed recently. We assume 54, the permutation group of four objects as flavor symmetry giving tri-bimaximal lepton mixing at leading order. In these models the second massive neutrino state is assumed quasi-Dirac and the remaining neutrinos are Majorana states. In the case of inverse mass hierarchy, the lower bound on the neutrinoless double beta decay parameter m(ee) is about two times that of the usual lower bound, within the range of sensitivity of the next generation of experiments. |
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Address |
[Morisi, S; Peinado, E] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, E-46071 Valencia, Spain, Email: morisi@ific.uv.es |
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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 |
0370-2693 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
WOS:000292994100011 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
700 |
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