236 research outputs found
Design and test of an extremely high resolution Timing Counter for the MEG II experiment: preliminary results
The design and tests of Timing Counter elements for the upgrade of the MEG
experiment, MEG II,is presented. The detector is based on several small plates
of scintillator with a Silicon PhotoMultipliers dual-side readout. The
optimisation of the single counter elements (SiPMs, scintillators, geometry) is
described. Moreover, the results obtained with a first prototype tested at the
Beam Test Facility (BTF) of the INFN Laboratori Nazionali di Frascati (LNF) are
presented.Comment: 10 pages, 7 figures. Presented at the 13th Topical Seminar on
Innovative Particle and Radiation Detectors (IPRD13) 7-10 October 2013 Siena,
Ital
First report of Colletotrichum theobromicola and C. tropicale causing Anthracnose on fruits of Carnauba palm in Brazil.
Made available in DSpace on 2018-07-12T01:03:52Z (GMT). No. of bitstreams: 1
ART18036.pdf: 288445 bytes, checksum: 0d5022966fb2c0ea9bb92b9d8774ef8c (MD5)
Previous issue date: 2018-07-09bitstream/item/179596/1/ART18036.pd
First report of Lasiodiplodia brasiliense causing postharvest fruit rot of Custard Apple (Annona squamosa) in Brazil.
Made available in DSpace on 2018-07-12T01:03:41Z (GMT). No. of bitstreams: 1
ART18038.pdf: 298918 bytes, checksum: 119259227882f2be45395ab20d9be69b (MD5)
Previous issue date: 2018-07-09bitstream/item/179595/1/ART18038.pd
First Report of Lasiodiplodia brasiliense Causing Disease in Apple Trees in Brazil .
In the last years, several apple varieties have been well-adapted to grow under the tropical conditions of northeastern Brazil.Nota Técnic
Absorption of Scintillation Light in a 100 Liquid Xenon Ray Detector and Expected Detector Performance
An 800L liquid xenon scintillation ray detector is being developed
for the MEG experiment which will search for decay
at the Paul Scherrer Institut. Absorption of scintillation light of xenon by
impurities might possibly limit the performance of such a detector. We used a
100L prototype with an active volume of 372x372x496 mm to study the
scintillation light absorption. We have developed a method to evaluate the
light absorption, separately from elastic scattering of light, by measuring
cosmic rays and sources. By using a suitable purification technique,
an absorption length longer than 100 cm has been achieved. The effects of the
light absorption on the energy resolution are estimated by Monte Carlo
simulation.Comment: 18 pages, 10 figures (eps). Submitted to Nucl. Instr. and Meth.
The cosmic ray positron excess and neutralino dark matter
Using a new instrument, the HEAT collaboration has confirmed the excess of
cosmic ray positrons that they first detected in 1994. We explore the
possibility that this excess is due to the annihilation of neutralino dark
matter in the galactic halo. We confirm that neutralino annihilation can
produce enough positrons to make up the measured excess only if there is an
additional enhancement to the signal. We quantify the `boost factor' that is
required in the signal for various models in the Minimal Supersymmetric
Standard Model parameter space, and study the dependence on various parameters.
We find models with a boost factor greater than 30. Such an enhancement in the
signal could arise if we live in a clumpy halo. We discuss what part of
supersymmetric parameter space is favored (in that it gives the largest
positron signal), and the consequences for other direct and indirect searches
of supersymmetric dark matter.Comment: 11 pages, 6 figures, matches published version (PRD
The MEG detector for decay search
The MEG (Mu to Electron Gamma) experiment has been running at the Paul
Scherrer Institut (PSI), Switzerland since 2008 to search for the decay \meg\
by using one of the most intense continuous beams in the world. This
paper presents the MEG components: the positron spectrometer, including a thin
target, a superconducting magnet, a set of drift chambers for measuring the
muon decay vertex and the positron momentum, a timing counter for measuring the
positron time, and a liquid xenon detector for measuring the photon energy,
position and time. The trigger system, the read-out electronics and the data
acquisition system are also presented in detail. The paper is completed with a
description of the equipment and techniques developed for the calibration in
time and energy and the simulation of the whole apparatus.Comment: 59 pages, 90 figure
Influência das épocas de floração e dos períodos de proteção fenológica à infecção do oídio no clone de cajueiro-anão BRS 189.
Made available in DSpace on 2018-01-18T22:14:50Z (GMT). No. of bitstreams: 1
ART17076.pdf: 154908 bytes, checksum: 4ac1589dd9389c98cb969c4e4e4a37a7 (MD5)
Previous issue date: 2018-01-15bitstream/item/171363/1/ART17076.pd
New constraint on the existence of the mu+-> e+ gamma decay
The analysis of a combined data set, totaling 3.6 \times 10^14 stopped muons
on target, in the search for the lepton flavour violating decay mu^+ -> e^+
gamma is presented. The data collected by the MEG experiment at the Paul
Scherrer Institut show no excess of events compared to background expectations
and yield a new upper limit on the branching ratio of this decay of 5.7 \times
10^-13 (90% confidence level). This represents a four times more stringent
limit than the previous world best limit set by MEG.Comment: 5 pages, 3 figures, a version accepted in Phys. Rev. Let
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