5,553 research outputs found
The ALICE TPC, a large 3-dimensional tracking device with fast readout for ultra-high multiplicity events
The design, construction, and commissioning of the ALICE Time-Projection
Chamber (TPC) is described. It is the main device for pattern recognition,
tracking, and identification of charged particles in the ALICE experiment at
the CERN LHC. The TPC is cylindrical in shape with a volume close to 90 m^3 and
is operated in a 0.5 T solenoidal magnetic field parallel to its axis.
In this paper we describe in detail the design considerations for this
detector for operation in the extreme multiplicity environment of central
Pb--Pb collisions at LHC energy. The implementation of the resulting
requirements into hardware (field cage, read-out chambers, electronics),
infrastructure (gas and cooling system, laser-calibration system), and software
led to many technical innovations which are described along with a presentation
of all the major components of the detector, as currently realized. We also
report on the performance achieved after completion of the first round of
stand-alone calibration runs and demonstrate results close to those specified
in the TPC Technical Design Report.Comment: 55 pages, 82 figure
Micropattern gas detector technologies and applications, the work of the RD51 collaboration
The RD51 collaboration was founded in April 2008 to coordinate and facilitate
efforts for development of micropattern gaseous detectors (MPGDs). The 75
institutes from 25 countries bundle their effort, experience and resources to
develop these emerging micropattern technologies.
MPGDs are already employed in several nuclear and high-energy physics
experiments, medical imaging instruments and photodetection applications; many
more applications are foreseen. They outperform traditional wire chambers in
terms of rate capability, time and position resolution, granularity, stability
and radiation hardness. RD51 supports efforts to make MPGDs also suitable for
large areas, increase cost-efficiency, develop portable detectors and improve
ease-of-use.
The collaboration is organized in working groups which develop detectors with
new geometries, study and simulate their properties, and design optimized
electronics. Among the common supported projects are creation of test
infrastructure such as beam test and irradiation facilities, and the production
workshop.Comment: Submitted to the IEEE Nuclear Science Symposium 2010 Conference
Recor
LArPix: Demonstration of low-power 3D pixelated charge readout for liquid argon time projection chambers
We report the demonstration of a low-power pixelated readout system designed
for three-dimensional ionization charge detection and digital readout of liquid
argon time projection chambers (LArTPCs). Unambiguous 3D charge readout was
achieved using a custom-designed system-on-a-chip ASIC (LArPix) to uniquely
instrument each pad in a pixelated array of charge-collection pads. The LArPix
ASIC, manufactured in 180 nm bulk CMOS, provides 32 channels of
charge-sensitive amplification with self-triggered digitization and multiplexed
readout at temperatures from 80 K to 300 K. Using an 832-channel LArPix-based
readout system with 3 mm spacing between pads, we demonstrated low-noise
(500 e RMS equivalent noise charge) and very low-power (100
W/channel) ionization signal detection and readout. The readout was used
to successfully measure the three-dimensional ionization distributions of
cosmic rays passing through a LArTPC, free from the ambiguities of existing
projective techniques. The system design relies on standard printed circuit
board manufacturing techniques, enabling scalable and low-cost production of
large-area readout systems using common commercial facilities. This
demonstration overcomes a critical technical obstacle for operation of LArTPCs
in high-occupancy environments, such as the near detector site of the Deep
Underground Neutrino Experiment (DUNE).Comment: 19 pages, 10 figures, 1 ancillary animation. V3 includes minor
revisions based on referee comment
Development of a time-to-digital converter ASIC for the upgrade of the ATLAS Monitored Drift Tube detector
The upgrade of the ATLAS muon spectrometer for high-luminosity LHC requires
new trigger and readout electronics for the various elements of the detector.
We present the design of a time-to-digital converter (TDC) ASIC prototype for
the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a
GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and
power consumption characteristics meet the design specifications, with a timing
bin variation of 40 ps for all 48 channels with a power consumption of about
6.5 mW per channel.Comment: 9 pages, 12 figure
Noise Characterization and Filtering in the MicroBooNE Liquid Argon TPC
The low-noise operation of readout electronics in a liquid argon time
projection chamber (LArTPC) is critical to properly extract the distribution of
ionization charge deposited on the wire planes of the TPC, especially for the
induction planes. This paper describes the characteristics and mitigation of
the observed noise in the MicroBooNE detector. The MicroBooNE's single-phase
LArTPC comprises two induction planes and one collection sense wire plane with
a total of 8256 wires. Current induced on each TPC wire is amplified and shaped
by custom low-power, low-noise ASICs immersed in the liquid argon. The
digitization of the signal waveform occurs outside the cryostat. Using data
from the first year of MicroBooNE operations, several excess noise sources in
the TPC were identified and mitigated. The residual equivalent noise charge
(ENC) after noise filtering varies with wire length and is found to be below
400 electrons for the longest wires (4.7 m). The response is consistent with
the cold electronics design expectations and is found to be stable with time
and uniform over the functioning channels. This noise level is significantly
lower than previous experiments utilizing warm front-end electronics.Comment: 36 pages, 20 figure
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