7 research outputs found
Recent updates on the ArDM project: A Liquid Argon TPC for Dark Matter Detection
ArDM is a new-generation WIMP detector which will measure simultaneously
light and charge from scintillation and ionization of liquid argon. Our goal is
to construct, characterize and operate a 1 ton liquid argon underground
detector. The project relies on the possibility to extract the electrons
produced by ionization from the liquid into the gas phase of the detector, to
amplify and read out with Large Electron Multipliers detectors. Argon VUV
scintillation light has to be converted with wavelength shifters such as
TetraPhenyl Butadiene in order to be detected by photomultipliers with bialkali
photocathodes. We describe the status of the LEM based charge readout and light
readout system R&D and the first light readout tests with warm and cold argon
gas in the full size detector.Comment: 10 pages, 9 figures, Talk given at the XIII International Conference
on Calorimetry in High Energy Physics (CALOR08), May 2008, Pavia, Ital
First results on light readout from the 1-ton ArDM liquid argon detector for dark matter searches
ArDM-1t is the prototype for a next generation WIMP detector measuring both
the scintillation light and the ionization charge from nuclear recoils in a
1-ton liquid argon target. The goal is to reach a minimum recoil energy of
30\,keVr to detect recoiling nuclei. In this paper we describe the experimental
concept and present results on the light detection system, tested for the first
time in ArDM on the surface at CERN. With a preliminary and incomplete set of
PMTs, the light yield at zero electric field is found to be between 0.3-0.5
phe/keVee depending on the position within the detector volume, confirming our
expectations based on smaller detector setups.Comment: 14 pages, 10 figures, v2 accepted for publication in JINS
Towards a liquid Argon TPC without evacuation: filling of a 6 m^3 vessel with argon gas from air to ppm impurities concentration through flushing
In this paper we present a successful experimental test of filling a volume
of 6 m with argon gas, starting from normal ambient air and reducing the
impurities content down to few parts per million (ppm) oxygen equivalent. This
level of contamination was directly monitored measuring the slow component of
the scintillation light of the Ar gas, which is sensitive to {\it all} sources
of impurities affecting directly the argon scintillation.Comment: 9 pages, 6 figures, to appear in Proc. 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba,
March 201
Underground Neutrino Detectors for Particle and Astroparticle Science: the Giant Liquid Argon Charge Imaging ExpeRiment (GLACIER)
The current focus of the CERN program is the Large Hadron Collider (LHC),
however, CERN is engaged in long baseline neutrino physics with the CNGS
project and supports T2K as recognized CERN RE13, and for good reasons: a
number of observed phenomena in high-energy physics and cosmology lack their
resolution within the Standard Model of particle physics; these puzzles include
the origin of neutrino masses, CP-violation in the leptonic sector, and baryon
asymmetry of the Universe. They will only partially be addressed at LHC. A
positive measurement of would certainly give a
tremendous boost to neutrino physics by opening the possibility to study CP
violation in the lepton sector and the determination of the neutrino mass
hierarchy with upgraded conventional super-beams. These experiments (so called
``Phase II'') require, in addition to an upgraded beam power, next generation
very massive neutrino detectors with excellent energy resolution and high
detection efficiency in a wide neutrino energy range, to cover 1st and 2nd
oscillation maxima, and excellent particle identification and
background suppression. Two generations of large water Cherenkov
detectors at Kamioka (Kamiokande and Super-Kamiokande) have been extremely
successful. And there are good reasons to consider a third generation water
Cherenkov detector with an order of magnitude larger mass than Super-Kamiokande
for both non-accelerator (proton decay, supernovae, ...) and accelerator-based
physics. On the other hand, a very massive underground liquid Argon detector of
about 100 kton could represent a credible alternative for the precision
measurements of ``Phase II'' and aim at significantly new results in neutrino
astroparticle and non-accelerator-based particle physics (e.g. proton decay).Comment: 31 pages, 14 figure
Development of wavelength shifter coated reflectors for the ArDM argon dark matter detector
To optimise the design of the light readout in the ArDM 1-ton liquid argon
dark matter detector, a range of reflector and WLS coating combinations were
investigated in several small setups, where argon scintillation light was
generated by radioactive sources in gas at normal temperature and pressure and
shifted into the blue region by tetraphenyl butadiene (TPB). Various
thicknesses of TPB were deposited by spraying and vacuum evaporation onto
specular 3M{\small\texttrademark}-foil and diffuse
Tetratex{\small\textregistered} (TTX) substrates. Light yields of each
reflector and TPB coating combination were compared. Reflection coefficients of
TPB coated reflectors were independently measured using a spectroradiometer in
a wavelength range between 200 and 650 nm. WLS coating on the PMT window was
also studied. These measurements were used to define the parameters of the
light reflectors of the ArDM experiment. Fifteen large cm
TTX sheets were coated and assembled in the detector. Measurements in argon gas
are reported providing good evidence of fulfilling the light collection
requirements of the experiment.Comment: 21 pages, 17 figure