445 research outputs found
Stable operation with gain of a double phase Liquid Argon LEM-TPC with a 1 mm thick segmented LEM
In this paper we present results from a test of a small Liquid Argon Large
Electron Multiplier Time Projection Chamber (LAr LEM-TPC). This detector
concept provides a 3D-tracking and calorimetric device capable of charge
amplification, suited for next-generation neutrino detectors and possibly
direct Dark Matter searches. During a test of a 3~lt chamber equipped with a
1010~cm readout, cosmic muon data was recorded during three weeks
of data taking. A maximum gain of 6.5 was achieved and the liquid argon was
kept pure enough to ensure 20~cm drift (O(ppb)~O equivalent).Comment: 7 pages, 6 figures, to appear in Proc. of 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba
(Japan), March 201
Test of a Liquid Argon TPC in a magnetic field and investigation of high temperature superconductors in liquid argon and nitrogen
Tests with cosmic ray muons of a small liquid argon time projection chamber
(LAr TPC) in a magnetic field of 0.55 T are described. No effect of the
magnetic field on the imaging properties were observed. In view of a future
large, magnetized LAr TPC, we investigated the possibility to operate a high
temperature superconducting (HTS) solenoid directly in the LAr of the detector.
The critical current of HTS cables in an external magnetic field was
measured at liquid nitrogen and liquid argon temperatures and a small prototype
HTS solenoid was built and tested.Comment: 5 pages, 5 figures, to appear in Proc. of 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba
(Japan), March 201
First operation and drift field performance of a large area double phase LAr Electron Multiplier Time Projection Chamber with an immersed Greinacher high-voltage multiplier
We have operated a liquid-argon large-electron-multiplier time-projection
chamber (LAr LEM-TPC) with a large active area of 76 40 cm and a
drift length of 60 cm. This setup represents the largest chamber ever achieved
with this novel detector concept. The chamber is equipped with an immersed
built-in cryogenic Greinacher multi-stage high-voltage (HV) multiplier, which,
when subjected to an external AC HV of 1 kV, statically
charges up to a voltage a factor of 30 higher inside the LAr vessel,
creating a uniform drift field of 0.5 kV/cm over the full drift length.
This large LAr LEM-TPC was brought into successful operation in the
double-phase (liquid-vapor) operation mode and tested during a period of
1 month, recording impressive three-dimensional images of very
high-quality from cosmic particles traversing or interacting in the sensitive
volume. The double phase readout and HV systems achieved stable operation in
cryogenic conditions demonstrating their good characteristics, which
particularly suit applications for next-generation giant-scale LAr-TPCs.Comment: 26 pages, 19 figure
Feasibility of high-voltage systems for a very long drift in liquid argon TPCs
Designs of high-voltage (HV) systems for creating a drift electric field in
liquid argon TPCs are reviewed. In ongoing experiments systems capable of
approx. 100 kV are realised for a drift field of 0.5-1 kV/cm over a length of
up to 1.5 m. Two of them having different approaches are presented: (1) the
ICARUS-T600 detector having a system consisting of an external power supply, HV
feedthroughs and resistive voltage degraders and (2) the ArDM-1t detector
having a cryogenic Greinacher HV multiplier inside the liquid argon volume. For
a giant scale liquid argon TPC, a system providing 2 MV may be required to
attain a drift length of approx. 20 m. Feasibility of such a system is
evaluated by extrapolating the existing designs.Comment: 8 pages, 13 figures, to appear in Proc. of 1st International Workshop
towards the Giant Liquid Argon Charge Imaging Experiment (GLA2010), Tsukuba
(Japan), March 201
First operation of a double phase LAr Large Electron Multiplier Time Projection Chamber with a two-dimensional projective readout anode
We have previously reported on the construction and successful operation of
the novel double phase Liquid Argon Large Electron Multiplier Time Projection
Chamber (LAr LEM-TPC). This detector concept provides a 3D-tracking and
calorimetric device capable of adjustable charge amplification, a promising
readout technology for next-generation neutrino detectors and direct Dark
Matter searches. In this paper, we report on the first operation of a LAr
LEM-TPC prototype - with an active area of 1010 cm and 21 cm drift
length - equipped with a single 1 mm thick LEM amplifying stage and a two
dimensional projective readout anode. Cosmic muon events were collected, fully
reconstructed and used to characterize the performance of the chamber. The
obtained signals provide images of very high quality and the energy loss
distributions of minimum ionizing tracks give a direct estimate of the
amplification. We find that a stable gain of 27 can be achieved with this
detector configuration corresponding to a signal-over-noise ratio larger than
200 for minimum ionizing tracks. The decoupling of the amplification stage and
the use of the 2D readout anode offer several advantages which are described in
the text.Comment: 25 pages, 17 figure
First operation and performance of a 200 lt double phase LAr LEM-TPC with a 40x76 cm^2 readout
In this paper we describe the design, construction, and operation of a first
large area double-phase liquid argon Large Electron Multiplier Time Projection
Chamber (LAr LEM-TPC). The detector has a maximum drift length of 60 cm and the
readout consists of a cm LEM and 2D projective anode to
multiply and collect drifting charges. Scintillation light is detected by means
of cryogenic PMTs positioned below the cathode. To record both charge and light
signals, we have developed a compact acquisition system, which is scalable up
to ton-scale detectors with thousands of charge readout channels. The
acquisition system, as well as the design and the performance of custom-made
charge sensitive preamplifiers, are described. The complete experimental setup
has been operated for a first time during a period of four weeks at CERN in the
cryostat of the ArDM experiment, which was equipped with liquid and gas argon
purification systems. The detector, exposed to cosmic rays, recorded events
with a single-channel signal-to-noise ratio in excess of 30 for minimum
ionising particles. Cosmic muon tracks and their -rays were used to
assess the performance of the detector, and to estimate the liquid argon purity
and the gain at different amplification fields.Comment: 23 pages, 21 figure
The Argon Dark Matter Experiment (ArDM)
The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for
the detection of dark matter particles which can scatter off the spinless argon
nuclei. These events producing a recoiling nucleus will be discerned by their
light to charge ratio, as well as the time structure of the scintillation
light. The experiment is presently under construction and will be commissioned
on surface at CERN. Here we describe the detector concept and give a short
review on the main detector components.Comment: Proceedings of 4th Patras workshop (DESY) on Axions, Wimps and Wisps
(4 pages, 4 figures
Giant Liquid Argon Observatory for Proton Decay, Neutrino Astrophysics and CP-violation in the Lepton Sector (GLACIER)
GLACIER (Giant Liquid Argon Charge Imaging ExpeRiment) is a large underground
observatory for proton decay search, neutrino astrophysics and CP-violation
studies in the lepton sector. Possible underground sites are studied within the
FP7 LAGUNA project (Europe) and along the JPARC neutrino beam in collaboration
with KEK (Japan). The concept is scalable to very large masses.Comment: 4 pages, 1 figure, Contribution to the Workshop "European Strategy
for Future Neutrino Physics", CERN, Oct. 200
ArDM: first results from underground commissioning
The Argon Dark Matter experiment is a ton-scale double phase argon Time
Projection Chamber designed for direct Dark Matter searches. It combines the
detection of scintillation light together with the ionisation charge in order
to discriminate the background (electron recoils) from the WIMP signals
(nuclear recoils). After a successful operation on surface at CERN, the
detector was recently installed in the underground Laboratorio Subterr\'aneo de
Canfranc, and the commissioning phase is ongoing. We describe the status of the
installation and present first results from data collected underground with the
detector filled with gas argon at room temperature.Comment: 6 pages, 3 figures, Light Detection In Noble Elements (LIDINE 2013
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