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Author |
Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
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Title |
The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
6 |
Issue |
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Pages |
P01003 - 16pp |
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Keywords |
Cherenkov detectors; Large detector systems for particle and astroparticle physics; Particle detectors |
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Abstract |
Since data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found. |
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Address |
[Abreu, P.; Andringa, S.; Assis, P.; Brogueira, P.; Cazon, L.; Conceicao, R.; Goncalves, P.; Pimenta, M.; Santo, C. E.; Santos, E.; Tome, B.] LIP, P-1000 Lisbon, Portugal |
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Publisher |
Iop Publishing Ltd |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
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Expedition |
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Conference |
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Notes |
ISI:000291345600003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial  |
646 |
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Author |
Linhart, V.; Burdette, D.; Chessi, E.; Cindro, V.; Clinthorne, N.H.; Cochran, E.; Grosicar, B.; Honscheid, K.; Kagan, H.; Lacasta, C.; Llosa, G.; Mikuz, M.; Stankova, V.; Studen, A.; Weilhammer, P.; Zontar, D. |
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Title |
Spectroscopy study of imaging devices based on silicon Pixel Array Detector coupled to VATAGP7 read-out chips |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
6 |
Issue |
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Pages |
C01092 - 8pp |
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Keywords |
Gamma camera, SPECT, PET PET/CT, coronary CT angiography (CTA); Compton imaging |
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Abstract |
Spectroscopic and timing response studies have been conducted on a detector module consisting of a silicon Pixel Array Detector bonded on two VATAGP7 read-out chips manufactured by Gamma-Medica Ideas using laboratory gamma sources and the internal calibration facilities (the calibration system of the read-out chips). The performed tests have proven that the chips have (i) non-linear calibration curves which can be approximated by power functions, (ii) capability to measure the energy of photons with energy resolution better than 2 keV (exact range and resolution depend on experimental setup), (iii) the internal calibration facility which provides 6 out of 16 available internal calibration charges within our region of interest (spanning the Compton edge of 511 keV photons). The peaks induced by the internal calibration facility are suitable for a fit of the calibration curves. However, they are not suitable for measurements of equivalent noise charge because their full width at half maximum varies with their amplitude. These facts indicate that the VATAGP7 chips are useful and precise tools for a wide variety of spectroscopic devices. We have also explored time walk of the module and peaking time of the spectroscopy signals provided by the chips. We have observed that (iv) the time walk is caused partly by the peaking time of the signals provided by the fast shaper of the chips and partly by the timing uncertainty related to the varying position of the photon interaction, (v) the peaking time of the spectroscopy signals provided by the chips increases with increasing pulse height. |
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Address |
[Linhart, V.; Lacasta, C.; Llosa, G.; Stankova, V.] UVEG, CSIC, IFIC, Expt Phys Dept,Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: Vladimir.Linhart@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
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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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Expedition |
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Conference |
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Notes |
ISI:000291345600097 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
645 |
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Author |
Marco-Hernandez, R. |
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Title |
Development of a beam test telescope based on the Alibava readout system |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
6 |
Issue |
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Pages |
C01002 - 7pp |
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Keywords |
Particle tracking detectors; Data acquisition circuits; Front-end electronics for detector readout; Digital electronic circuits |
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Abstract |
A telescope for a beam test have been developed as a result of a collaboration among the University of Liverpool, Centro Nacional de Microelectronica (CNM) of Barcelona and Instituto de Fisica Corpuscular (IFIC) of Valencia. This system is intended to carry out both analogue charge collection and spatial resolution measurements with different types of microstrip or pixel silicon detectors in a beam test environment. The telescope has four XY measurement as well as trigger planes (XYT board) and it can accommodate up to twelve devices under test (DUT board). The DUT board uses two Beetle ASICs for the readout of chilled silicon detectors. The board could operate in a self-triggering mode. The board features a temperature sensor and it can be mounted on a rotary stage. A peltier element is used for cooling the DUT. Each XYT board measures the track space points using two silicon strip detectors connected to two Beetle ASICs. It can also trigger on the particle tracks in the beam test. The board includes a CPLD which allows for the synchronization of the trigger signal to a common clock frequency, delaying and implementing coincidence with other XYT boards. An Alibava mother board is used to read out and to control each XYT/DUT board from a common trigger signal and a common clock signal. The Alibava board has a TDC on board to have a time stamp of each trigger. The data collected by each Alibava board is sent to a master card by means of a local data/address bus following a custom digital protocol. The master board distributes the trigger, clock and reset signals. It also merges the data streams from up to sixteen Alibava boards. The board has also a test channel for testing in a standard mode a XYT or DUT board. This board is implemented with a Xilinx development board and a custom patch board. The master board is connected with the DAQ software via 100M Ethernet. Track based alignment software has also been developed for the data obtained with the DAQ software. |
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Address |
[Marco-Hernandez, R.; Alibava Collaboration] CSIC UV, Inst Fis Corpuscular, E-46980 Paterna, Valencia, Spain, Email: rmarco@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
1748-0221 |
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Expedition |
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Conference |
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Notes |
ISI:000291345600007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
644 |
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Author |
Baker, M.J.; Bordes, J.; Hong-Mo, C.; Tsun, T.S. |
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Title |
Mass Hierarchy, Mixing, CP-Violation And Higgs Decay – Or Why Rotation Is Good For Us |
Type |
Journal Article |
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Year |
2011 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
26 |
Issue |
13 |
Pages |
2087-2124 |
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Keywords |
Quark and lepton mixing; mass hierarchy; CP violation; rotation |
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Abstract |
The idea of a rank-one rotating mass matrix (R2M2) is reviewed detailing how it leads to ready explanations both for the fermion mass hierarchy and for the distinctive mixing patterns between up and down fermion states, which can be and have been tested against experiment and shown to be fully consistent with existing data. Further, R2M2 is seen to offer, as by-products: (i) a new solution to the strong CP problem in QCD by linking the theta-angle there to the Kobayashi-Maskawa CP-violating phase in the CKM matrix, and (ii) some novel predictions of possible anomalies in Higgs decay observable in principle at the LHC. A special effort is made to answer some questions raised. |
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Address |
[Baker, Michael J.; Tsun, Tsou Sheung] Univ Oxford, Inst Math, Oxford OX1 3LB, England, Email: bakerm@maths.ox.ac.uk |
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Publisher |
World Scientific Publ Co Pte Ltd |
Place of Publication |
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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 |
0217-751x |
ISBN |
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Conference |
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Notes |
ISI:000291219600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
643 |
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| Permanent link to this record |
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Author |
Mangano, G.; Miele, G.; Pastor, S.; Pisanti, O.; Sarikas, S. |
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Title |
Constraining the cosmic radiation density due to lepton number with Big Bang Nucleosynthesis |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
035 - 18pp |
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Keywords |
big bang nucleosynthesis; neutrino properties; cosmological neutrinos; physics of the early universe |
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Abstract |
The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N-eff. This quantity, in case of no extra degrees of freedom, depends upon the chemical potential and the temperature characterizing the three active neutrino distributions, as well as by their possible non-thermal features. In the present analysis we determine the upper bounds that BBN places on N-eff from primordial neutrino-antineutrino asymmetries, with a careful treatment of the dynamics of neutrino oscillations. We consider quite a wide range for the total lepton number in the neutrino sector, eta(nu) = eta(nu e) + eta(nu mu) + eta(nu tau) and the initial electron neutrino asymmetry eta(in)(nu e), solving the corresponding kinetic equations which rule the dynamics of neutrino (antineutrino) distributions in phase space due to collisions, pair processes and flavor oscillations. New bounds on both the total lepton number in the neutrino sector and the nu(e)-(nu) over bar (e) asymmetry at the onset of BBN are obtained fully exploiting the time evolution of neutrino distributions, as well as the most recent determinations of primordial H-2/H density ratio and He-4 mass fraction. Note that taking the baryon fraction as measured by WMAP, the H-2/H abundance plays a relevant role in constraining the allowed regions in the eta(nu)-eta(in)(nu e) plane. These bounds fix the maximum contribution of neutrinos with primordial asymmetries to N-eff as a function of the mixing parameter theta(13), and point out the upper bound N-eff less than or similar to 3.4. Comparing these results with the forthcoming measurement of N-eff by the Planck satellite will likely provide insight on the nature of the radiation content of the universe. |
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Address |
[Mangano, Gianpiero; Miele, Gennaro; Pisanti, Ofelia; Sarikas, Srdjan] Ist Nazl Fis Nucl, Sez Napoli, I-80126 Naples, Italy, Email: mangano@na.infn.it |
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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 |
1475-7516 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000291258300035 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
642 |
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| Permanent link to this record |
