115 research outputs found
A hardware implementation of Region-of-Interest selection in LAr-TPC for data reduction and triggering
Large Liquid Argon TPC detectors in the range of multikton mass for neutrino
and astroparticle physics require the extraction and treatment of signals from
some 105 wires. In order to enlarge the throughtput of the DAQ system an
on-line lossless data compression has been realized reducing almost a factor 4
the data flow. Moreover a trigger system based on a new efficient on-line
identification algorithm of wire hits was studied, implemented on the actual
ICARUS digital read- out boards and fully tested on the ICARINO LAr-TPC
facility operated at LNL INFN Laboratory with cosmic-rays. Capability to
trigger isolated low energy events down to 1 MeV visible energy was also
demonstrated.Comment: 26 pages, 26 Figure; to be submitted to JINS
A new search for anomalous neutrino oscillations at the CERN-PS
The LSND experiment has observed a 3.8 sigma excess of anti-nu_e events from
an anti-nu_mu beam coming from pions at rest. If confirmed, the LSND anomaly
would imply new physics beyond the standard model, presumably in the form of
some additional sterile neutrinos. The MiniBooNE experiment at FNAL-Booster has
further searched for the LSND anomaly. Above 475 MeV, the nu_e result is
excluding the LSND anomaly to about 1.6 sigma but it introduces an unexplained,
new 3.0 sigma anomaly at lower energies, down to 200 MeV. The nu_e data have so
far an insufficient statistics to be conclusive with LSND's anti-nu_e. The
present proposal at the CERN-PS is based on two strictly identical LAr-TPC
detectors in the near and far positions, respectively at 127 and 850 m from the
neutrino (or antineutrino) target and focussing horn, observing the
electron-neutrino signal. This project will benefit from the already developed
technology of ICARUS T600, well tested on surface in Pavia, without the need of
any major R&D activity and without the added problems of an underground
experiment (CNGS-2). The superior quality of the Liquid Argon imaging TPC and
its unique electron - pi-zero discrimination allow full rejection of the NC
background, without efficiency loss for electron neutrino detection. In two
years of exposure, the far detector mass of 600 tons and a reasonable
utilization of the CERN-PS with the refurbished previous TT7 beam line will
allow to collect about 10^6 charged current events, largely adequate to settle
definitely the LSND anomaly.Comment: 23 pages, 17 figures, added watermark, better referencin
Operation of a LAr-TPC equipped with a multilayer LEM charge readout
A novel detector for the ionization signal in a single phase LAr-TPC, based
on the adoption of a multilayer Large Electron Multiplier (LEM) replacing the
traditional anodic wire arrays, has been experimented in the ICARINO test
facility at the INFN Laboratories in Legnaro. Cosmic muon tracks were detected
allowing the measurement of energy deposition and a first determination of the
signal to noise ratio. The analysis of the recorded events demonstrated the 3D
reconstruction capability of ionizing events in this device in liquid Argon,
collecting a fraction of about 90% of the ionization signal with signal to
noise ratio similar to that measured with more traditional wire chambersComment: 9 pages, 7 Figure
Free electron lifetime achievements in Liquid Argon Imaging TPC
A key feature for the success of the liquid Argon imaging TPC (LAr-TPC)
technology is the industrial purification against electro-negative impurities,
especially Oxygen and Nitrogen remnants, which have to be continuously kept at
an exceptionally low level by filtering and recirculating liquid Argon.
Improved purification techniques have been applied to a 120 liters LAr-TPC test
facility in the INFN-LNL laboratory. Through-going muon tracks have been used
to determine the free electron lifetime in liquid Argon against
electro-negative impurities. The short path length here observed (30 cm) is
compensated by the high accuracy in the observation of the specific ionization
of cosmic ray muons at sea level as a function of the drift distance. A free
electron lifetime of (21.4+7.3-4.3) ms, namely > 15.8 ms at 90 % C.L. has been
observed over several weeks under stable conditions, corresponding to a
residual Oxygen equivalent of about 15 ppt (part per trillion). At 500 V/cm,
the free electron speed is 1.5 m/ms. In a LAr-TPC a free electron lifetime in
excess of 15 ms corresponds for instance to an attenuation of less than 15 %
after a drift path of 5 m, opening the way to the operation of the LAr-TPC with
exceptionally long drift distances.Comment: 15 pages, 10 figures; Accepted for publication in JINS
Measurement of the two-photon absorption cross-section of liquid argon with a time projection chamber
This paper reports on laser-induced multiphoton ionization at 266 nm of
liquid argon in a time projection chamber (LAr TPC) detector. The electron
signal produced by the laser beam is a formidable tool for the calibration and
monitoring of next-generation large-mass LAr TPCs. The detector that we
designed and tested allowed us to measure the two-photon absorption
cross-section of LAr with unprecedented accuracy and precision:
sigma_ex=(1.24\pm 0.10stat \pm 0.30syst) 10^{-56} cm^4s{-1}.Comment: 15 pages, 9 figure
MiniBooNE Oscillation Results 2011
The MiniBooNE neutrino oscillation search experiment at Fermilab has recently
updated results from a search for
oscillations, using a data sample corresponding to
protons on target in anti-neutrino mode. This high statistics result represent
an increase in statistics of 52% compared to result published in 2010. An
excess of 57.7 28.5 events is observed in the energy range 200 MeV 3000 MeV. The data favor LSND-like
oscillations over a background only hypothesis at 91.1% confidence level in the
energy range 475 3000 MeV.Comment: 4 pages, 6 figures, talk given at NuFact 2011, XIIIth
InternationalWorkshop on Neutrino Factories, Super beams and Beta beams,
CERN/UNIGE, Geneva, Switzerland, August 1-6, 201
Development and first tests of GEM-like detectors with resistive electrodes
We have developed and tested several prototypes of GEM-like detectors with electrodes coated with resistive layers or completely made of resistive materials. These detectors can operate stably at gains close to 105. The resistive layers limit the energy of discharges appearing at higher gains thus making the detectors very robust. We demonstrated that the cathodes of some of these detectors could be coated by CsI or SbCs layers to enhance the detection efficiency for the UV and visible photons. We also discovered that such detectors can operate stably in the cascade mode and high overall gains () are reachable. Applications in several areas, for example in RICH or in noble liquid TPCs are therefore possible. The first results from the detection of UV photons at room and cryogenic temperatures will be given
A local trigger system for the large LAr-TPC detector
A special dedicated double-rebinning algorithm has been successfully developed in order to extract the physical hit signal from the TPC wires. This solution has been implemented on digital boards, allowing to realize a local trigger able to identify even localized low-energy small events
Measurement of a large electron lifetime in a liquid argon TPC
An unprecedentedly high value of electron lifetime in a liquid argon TPC, about 21ms, has been measured in a test facility at INFN-LNL. This results opens the way to the future development of TPCs with very long drift distances
Design of a SiPM-based cluster for the Large Size Telescope camera of CTA
A Silicon Photomultiplier (SiPM)-based photodetector is being built to
demonstrate its feasibility for an alternative silicon-based camera design for
the Large Size Telescope (LST) of the Cherenkov Telescope Array. It has been
designed to match the size of the standard Photomultiplier Tube (PMT) cluster
unit and to be compatible with mechanics, electronics and focal plane optics of
the first LST camera. Here, we describe the overall SiPM cluster design along
with the main differences with respect to the currently used PMT cluster unit.
The fast electronics of the SiPM pixel and its layout are also presented. In
order to derive the best working condition for the final unit, we measured the
SiPM performances in terms of gain, photo-detection efficiency and cross-talk.
One pixel, a unit of 14 SiPMs, has been built. We will discuss also some
preliminary results regarding this device and we will highlight the future
steps of this project.Comment: submitted to NIM
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