Records |
Author |
Borja, E.F.; Garay, I.; Vidotto, F. |
Title |
Learning about Quantum Gravity with a Couple of Nodes |
Type |
Journal Article |
Year |
2012 |
Publication |
Symmetry Integrability and Geometry-Methods and Applications |
Abbreviated Journal |
Symmetry Integr. Geom. |
Volume |
8 |
Issue |
|
Pages |
015 - 44pp |
Keywords |
discrete gravity; canonical quantization; spinors; spinfoam; quantum cosmology |
Abstract |
Loop Quantum Gravity provides a natural truncation of the infinite degrees of freedom of gravity, obtained by studying the theory on a given finite graph. We review this procedure and we present the construction of the canonical theory on a simple graph, formed by only two nodes. We review the U(N) framework, which provides a powerful tool for the canonical study of this model, and a formulation of the system based on spinors. We consider also the covariant theory, which permits to derive the model from a more complex formulation, paying special attention to the cosmological interpretation of the theory. |
Address |
[Borja, Enrique F.; Garay, Inaki] Univ Erlangen Nurnberg, Inst Theoret Phys 3, D-91058 Erlangen, Germany, Email: efborja@theorie3.physik.uni-erlangen.de; |
Corporate Author |
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Thesis |
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Publisher |
Natl Acad Sci Ukraine, Inst Math |
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 |
1815-0659 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference ![sorted by Conference field, descending order (down)](img/sort_desc.gif) |
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Notes |
WOS:000303831400001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1018 |
Permanent link to this record |
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Author |
Yepes, H. |
Title |
The ANTARES neutrino detector instrumentation |
Type |
Journal Article |
Year |
2012 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
Volume |
7 |
Issue |
|
Pages |
C01022 - 9pp |
Keywords |
Large detector-systems performance; Performance of High Energy Physics Detectors; Detector alignment and calibration methods (lasers, sources, particle-beams) |
Abstract |
ANTARES is actually the fully operational and the largest neutrino telescope in the Northern hemisphere. Located in the Mediterranean Sea, it consists of a 3D array of 885 photomultiplier tubes (PMTs) arranged in 12 detection lines (25 storeys each), able to detect the Cherenkov light induced by upgoing relativistic muons produced in the interaction of high energy cosmic neutrinos with the detector surroundings. Among its physics goals, the search for neutrino astrophysical sources and the indirect detection of dark matter particles coming from the sun are of particular interest. To reach these goals, good accuracy in track reconstruction is mandatory, so several calibration systems for timing and positioning have been developed. In this contribution we will present the design of the detector, calibration systems, associated equipment and its performance on track reconstruction. |
Address |
Univ Valencia, CSIC, Inst Fis Corpuscular IFIC, E-46071 Valencia, Spain, Email: Harold.Yepes@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 ![sorted by Conference field, descending order (down)](img/sort_desc.gif) |
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Notes |
WOS:000303806200022 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
no |
Call Number |
IFIC @ pastor @ |
Serial |
1041 |
Permanent link to this record |
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Author |
Wurm, M. et al; Mena, O. |
Title |
The next-generation liquid-scintillator neutrino observatory LENA |
Type |
Journal Article |
Year |
2012 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
Volume |
35 |
Issue |
11 |
Pages |
685-732 |
Keywords |
Neutrino detectors; Liquid-scintillator detectors; Low-energy neutrinos; Proton decay; Longbaseline neutrino beams |
Abstract |
As part of the European LAGUNA design study on a next-generation neutrino detector, we propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a multipurpose neutrino observatory. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. Low energy threshold, good energy resolution and efficient background discrimination are inherent to the liquid-scintillator technique. A target mass of 50 kt will offer a substantial increase in detection sensitivity. At low energies, the variety of detection channels available in liquid scintillator will allow for an energy and flavor-resolved analysis of the neutrino burst emitted by a galactic Supernova. Due to target mass and background conditions, LENA will also be sensitive to the faint signal of the Diffuse Supernova Neutrino Background. Solar metallicity, time-variation in the solar neutrino flux and deviations from MSW-LMA survival probabilities can be investigated based on unprecedented statistics. Low background conditions allow to search for dark matter by observing rare annihilation neutrinos. The large number of events expected for geoneutrinos will give valuable information on the abundances of Uranium and Thorium and their relative ratio in the Earth's crust and mantle. Reactor neutrinos enable a high-precision measurement of solar mixing parameters. A strong radioactive or pion decay-at-rest neutrino source can be placed close to the detector to investigate neutrino oscillations for short distances and sub-MeV to MeV energies. At high energies, LENA will provide a new lifetime limit for the SUSY-favored proton decay mode into kaon and antineutrino, surpassing current experimental limits by about one order of magnitude. Recent studies have demonstrated that a reconstruction of momentum and energy of GeV particles is well feasible in liquid scintillator. Monte Carlo studies on the reconstruction of the complex event topologies found for neutrino interactions at multi-GeV energies have shown promising results. If this is confirmed. LENA might serve as far detector in a long-baseline neutrino oscillation experiment currently investigated in LAGUNA-LBNO. |
Address |
[Wurm, Michael; Bick, Daniel; Hagner, Caren; Lorenz, Sebastian] Univ Hamburg, Inst Expt Phys, Hamburg, Germany, Email: michael.wurm@desy.de |
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 |
0927-6505 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference ![sorted by Conference field, descending order (down)](img/sort_desc.gif) |
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Notes |
WOS:000304787800001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1054 |
Permanent link to this record |
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Author |
Carles, M.; Lerche, C.W.; Sanchez, F.; Mora, F.; Benlloch, J.M. |
Title |
Position correction with depth of interaction information for a small animal PET system |
Type |
Journal Article |
Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
Volume |
648 |
Issue |
|
Pages |
S176-S180 |
Keywords |
DOI; PET; Positioning algorithm; Gamma ray imaging; Continuous scintillators |
Abstract |
In this work we study the effects on the spatial resolution when depth of interaction (001) information is included in the parameterization of the line of response (LOR) for a small animal positron emission tomography (PET) system. One of the most important degrading factors for PET is the parallax error introduced in systems that do not provide DOI information of the recorded gamma-rays. Our group has designed a simple and inexpensive method for DOI determination in continuous scintillation crystals. This method is based, on one hand, in the correlation between the scintillation light distribution width in monolithic crystals and the DOI, and, on the other hand, on a small modification of the widely applied charge dividing circuits (CDR). In this work we present a new system calibration that includes the DOI information, and also the development of the correction equations that relates the LOR without and with DOI information. We report the results obtained for different measurements along the transaxial field of view (FOV) and the image quality enhancement achieved specially at the edge of the FOV. |
Address |
[Carles, M.; Sanchez, F.; Benlloch, J. M.] Inst Fis Corpuscular CSIC UV, Valencia 46071, Spain, Email: montcar@ific.uv.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 ![sorted by Conference field, descending order (down)](img/sort_desc.gif) |
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Notes |
WOS:000305376900046 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
no |
Call Number |
IFIC @ pastor @ |
Serial |
1067 |
Permanent link to this record |
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Author |
AGATA Collaboration; Doncel, M.; Quintana, B.; Gadea, A.; Recchia, F.; Farnea, E. |
Title |
Background rejection capabilities of a Compton imaging telescope setup with a DSSD Ge planar detector and AGATA |
Type |
Journal Article |
Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
Volume |
648 |
Issue |
|
Pages |
S131-S134 |
Keywords |
gamma-Spectroscopy; Gamma tracking; Imaging; Position-sensitive germanium detectors |
Abstract |
In this work, we show the first Monte Carlo results about the performance of the Ge array which we propose for the DESPEC experiment at FAIR, when the background algorithm developed for AGATA is applied. The main objective of our study is to characterize the capabilities of the gamma-spectroscopy system, made up of AGATA detectors in a semi-spherical distribution covering a 1 pi solid angle and a set of planar Ge detectors in a daisy configuration, to discriminate between gamma sources placed at different locations. |
Address |
[Doncel, M.; Quintana, B.] Univ Salamanca, Lab Radiac Ionizantes, E-37008 Salamanca, Spain, Email: doncel@usal.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 ![sorted by Conference field, descending order (down)](img/sort_desc.gif) |
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Notes |
WOS:000305376900035 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
1071 |
Permanent link to this record |