834 research outputs found
MicroTCA implementation of synchronous Ethernet-Based DAQ systems for large scale experiments
Large LAr TPCs are among the most powerful detectors to address open problems
in particle and astro-particle physics, such as CP violation in leptonic
sector, neutrino properties and their astrophysical implications, proton decay
search etc. The scale of such detector implies severe constraints on their
readout and DAQ system. In this article we describe a data acquisition scheme
for this new generation of large detectors. The main challenge is to propose a
scalable and easy to use solution able to manage a large number of channels at
the lowest cost. It is interesting to note that these constraints are very
similar to those existing in Network Telecommunication Industry. We propose to
study how emerging technologies like ATCA and TCA could be used in
neutrino experiments. We describe the design of an Advanced Mezzanine Board
(AMC) including 32 ADC channels. This board receives 32 analogical channels at
the front panel and sends the formatted data through the TCA backplane
using a Gigabit Ethernet link. The gigabit switch of the MCH is used to
centralize and to send the data to the event building computer. The core of
this card is a FPGA (ARIA-GX from ALTERA) including the whole system except the
memories. A hardware accelerator has been implemented using a NIOS II P
and a Gigabit MAC IP. Obviously, in order to be able to reconstruct the tracks
from the events a time synchronisation system is mandatory. We decided to
implement the IEEE1588 standard also called Precision Timing Protocol, another
emerging and promising technology in Telecommunication Industry. In this
article we describe a Gigabit PTP implementation using the recovered clock of
the gigabit link. By doing so the drift is directly cancelled and the PTP will
be used only to evaluate and to correct the offset.Comment: Talk presented at the 2009 Real Time Conference, Beijing, May '09,
submitted to the proceeding
Inter-laboratory synchronization for the CNGS project
JACoW web site http://accelconf.web.cern.ch/AccelConf/e06International audienceCERN will start sending a neutrino beam to Gran Sasso National Laboratory in Italy in July 2006. This beam will cover a distance of around 730 km through the crust of the earth from an extraction line in CERN's SPS to dedicated detectors in Gran Sasso. This paper describes the technological choices made to fulfill the specification of inter-laboratory synchronization in the region of 100 ns, as well as some preliminary results. The common time standard is UTC as disseminated by the GPS system, and the techniques are similar to those used by national metrology laboratories for the manufacturing of UTC itself. In addition, real-time messages sent through the Internet allow the detectors in Gran Sasso to go into calibration mode when no beam is being sent. Data concerning the delay and determinism of this international network link is also presented
The neutrino velocity anomaly as an explanation of the missing observation of neutrinos in coincidence with GRB
The search for neutrinos emitted in coincidence with Gamma-Bay Burst has been
so far unsuccessfully. In this paper we show that the recent result reported by
the OPERA Collaboration on an early arrival time of muon neutrinos with respect
to the one computed assuming the speed of light in vacuum could explain the
null search for neutrinos in coincidence with Gamma-Ray Burst
On the Role of Low-Energy CP Violation in Leptogenesis
The link between low-energy CP violation and leptogenesis became more
accessible with the understanding of flavor effects. However, a definite
well-motivated model where such a link occurs was still lacking. Adjoint SU(5)
is a simple grand unified theory where neutrino masses are generated through
the Type I and Type III seesaw mechanisms, and the lepton asymmetry is
generated by the fermionic triplet responsible for the Type III seesaw. We
focus exclusively on the case of inverted hierarchy for neutrinos, and we show
that successful flavored leptogenesis in this theory strongly points towards
low-energy CP violation. Moreover, since the range of allowed masses for the
triplet is very restricted, we find that the discovery at the LHC of new states
present in the theory, together with proton decay and unification of gauge
couplings, can conspire to provide a hint in favor of leptogenesis.Comment: 12 pages, 6 figure
Sterile neutrinos at future long baseline experiments
In this talk we review the current status of sterile neutrino searches and
discuss the potential of future long baseline experiments to study their
properties.Comment: 3 pages, 2 figures, talk given at NOW2008, Conca Specchiulla,
Otranto, Italy, September 6-13, 200
Testing whether muon neutrino flavor mixing is maximal
The small difference between the survival probabilities of muon neutrino and
antineutrino beams, traveling through earth matter in a long baseline
experiment such as MINOS, is shown to be an important measure of any possible
deviation from maximality in the flavor mixing of those states.Comment: Some revision has been made in the experimental discussions with two
new figures replacing the old ones and a clarification of the accuracy of the
perturbative result has been included. This version will be published in
Physical Review Letters. Title changed as asked by the editors of Physical
Review Letter
Neutrino physics at accelerators
Present and future neutrino experiments at accelerators are mainly concerned
with understanding the neutrino oscillation phenomenon and its implications.
Here a brief account of neutrino oscillations is given together with a
description of the supporting data. Some current and planned accelerator
neutrino experiments are also explained.Comment: 23 pages, 24 figures. Talk given at the Corfu Summer Institute on
Elementary Particle Physics 200
Low Energy Electron and Nuclear Recoil Thresholds in the DRIFT-II Negative Ion TPC for Dark Matter Searches
Understanding the ability to measure and discriminate particle events at the
lowest possible energy is an essential requirement in developing new
experiments to search for weakly interacting massive particle (WIMP) dark
matter. In this paper we detail an assessment of the potential sensitivity
below 10 keV in the 1 m^3 DRIFT-II directionally sensitive, low pressure,
negative ion time projection chamber (NITPC), based on event-by-event track
reconstruction and calorimetry in the multiwire proportional chamber (MWPC)
readout. By application of a digital smoothing polynomial it is shown that the
detector is sensitive to sulfur and carbon recoils down to 2.9 and 1.9 keV
respectively, and 1.2 keV for electron induced events. The energy sensitivity
is demonstrated through the 5.9 keV gamma spectrum of 55Fe, where the energy
resolution is sufficient to identify the escape peak. The effect a lower energy
sensitivity on the WIMP exclusion limit is demonstrated. In addition to recoil
direction reconstruction for WIMP searches this sensitivity suggests new
prospects for applications also in KK axion searches
Background studies and shielding effects for the TPC detector of the CAST experiment
Sunset solar axions traversing the intense magnetic field of the CERN Axion
Solar Telescope (CAST) experiment may be detected in a Time Projection Chamber
(TPC) detector, as X-rays signals. These signals could be masked, however, by
the inhomogeneous background of materials in the experimental site. A detailed
analysis, based on the detector characteristics, the background radiation at
the CAST site, simulations and experimental results, has allowed us to design a
shielding which reduces the background level by a factor of ~4 compared to the
detector without shielding, depending on its position, in the energy range
between 1 and 10 keV. Moreover, this shielding has improved the homogeneity of
background measured by the TPC.Comment: 14 pages, 5 figures, accepted in New Journal of Physic
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
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