64,644 research outputs found
High efficiency gaseous tracking detector for cosmic muon radiography
A tracking detector system has been constructed with an innovative approach
to the classical multi-wire proportional chamber concept, using contemporary
technologies. The detectors, covering an area of 0.58 square meters each, are
optimized for the application of muon radiography. The main features are high
(>99.5%) and uniform detection efficiency, 9 mm FWHM position resolution,
filling gas consumption below 2 liters per hour for the non toxic, non
flammable argon and carbon dioxide mixture. These parameters, along with the
simplicity of the construction and the tolerance for mechanical effects, make
the detectors to be a viable option for a large area muography observation
system.Comment: 15 pages, 15 figure
Anode-Coupled Readout for Light Collection in Liquid Argon TPCs
This paper will discuss a new method of signal read-out from photon detectors
in ultra-large, underground liquid argon time projection chambers. In this
design, the signal from the light collection system is coupled via capacitive
plates to the TPC wire-planes. This signal is then read out using the same
cabling and electronics as the charge information. This greatly benefits light
collection: it eliminates the need for an independent readout, substantially
reducing cost; It reduces the number of cables in the vapor region of the TPC
that can produce impurities; And it cuts down on the number of feed-throughs in
the cryostat wall that can cause heat-leaks and potential points of failure. We
present experimental results that demonstrate the sensitivity of a LArTPC wire
plane to photon detector signals. We also simulate the effect of a 1 s
shaping time and a 2 MHz sampling rate on these signals in the presence of
noise, and find that a single photoelectron timing resolution of 30 ns
can be achieved.Comment: 16 pages, 15 figure
A prototype liquid Argon Time Projection Chamber for the study of UV laser multi-photonic ionization
This paper describes the design, realization and operation of a prototype
liquid Argon Time Projection Chamber (LAr TPC) detector dedicated to the
development of a novel online monitoring and calibration system exploiting UV
laser beams. In particular, the system is intended to measure the lifetime of
the primary ionization in LAr, in turn related to the LAr purity level. This
technique could be exploited by present and next generation large mass LAr TPCs
for which monitoring of the performance and calibration plays an important
role. Results from the first measurements are presented together with some
considerations and outlook.Comment: 26 pages, 27 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
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