3,907 research outputs found
The Thin Gap Chambers database experience in test beam and preparations for ATLAS
Thin gap chambers (TGCs) are used for the muon trigger system in the forward
region of the LHC experiment ATLAS. The TGCs are expected to provide a trigger
signal within 25 ns of the bunch spacing. An extensive system test of the ATLAS
muon spectrometer has been performed in the H8 beam line at the CERN SPS during
the last few years. A relational database was used for storing the conditions
of the tests as well as the configuration of the system. This database has
provided the detector control system with the information needed for
configuration of the front end electronics. The database is used to assist the
online operation and maintenance. The same database is used to store the non
event condition and configuration parameters needed later for the offline
reconstruction software. A larger scale of the database has been produced to
support the whole TGC system. It integrates all the production, QA tests and
assembly information. A 1/12th model of the whole TGC system is currently in
use for testing the performance of this database in configuring and tracking
the condition of the system. A prototype of the database was first implemented
during the H8 test beams. This paper describes the database structure, its
interface to other systems and its operational performance.Comment: Proceedings IEEE, Nuclear Science Symposium 2005, Stockholm, Sweeden,
May 200
Using a neural network approach for muon reconstruction and triggering
The extremely high rate of events that will be produced in the future Large
Hadron Collider requires the triggering mechanism to take precise decisions in
a few nano-seconds. We present a study which used an artificial neural network
triggering algorithm and compared it to the performance of a dedicated
electronic muon triggering system. Relatively simple architecture was used to
solve a complicated inverse problem. A comparison with a realistic example of
the ATLAS first level trigger simulation was in favour of the neural network. A
similar architecture trained after the simulation of the electronics first
trigger stage showed a further background rejection.Comment: A talk given at ACAT03, KEK, Japan, November 2003. Submitted to
Nuclear Instruments and Methods in Physics Research, Section
The Certification of ATLAS Thin Gap Chambers Produced in Israel and China
Thin gap chambers (TGCs) are used for the muon trigger system in the forward
region of the LHC experiment ATLAS. A TGC consists of a plane of closely spaced
wires maintained at positive high voltage, sandwiched between resistive
grounded cathode planes with an anode wire to cathode plane gap distance
smaller than the wire-to-wire spacing. The TGCs are expected to provide a
trigger signal within 25 ns of the bunch spacing of the LHC accelerator, with
an efficiency exceeding 95%, while exposed to an effective photon and neutron
background ranging from 30 to 500 Hz/cm2. About 2,500 out of the 3,600 ATLAS
TGCs are being produced at the Weizmann institute in Israel, and in Shandong
University in China. Once installed in the ATLAS detector the TGCs will be
inaccessible. A vigorous production quality control program is therefore
implemented at the production sites. Furthermore, after chamber completion, a
thorough program of quality assurance is implemented to ensure the efficient
performance of the chambers during more than ten years of operation in the LHC
high rate environment. This program consists of a detailed mapping of the
detectors response using cosmic rays, as well as checking the chambers behavior
using a high rate radiation source. An aging test performed on five chambers in
a serial gas connection is presented. Finally the results of the chambers
certification tests performed at CERN before the installation in ATLAS are
described.Comment: Presented at 2004 IEEE Nuclear Science Symposium 2004, Rome, Oct 200
The Cosmic Ray Hodoscopes for Testing Thin Gap Chambers at the Technion and Tel Aviv University
Thin gap chambers (TGCs) are built for the muon trigger chambers in the
endcap region of the LHC experiment ATLAS. More than 2500 ATLAS TGCs are being
produced at the Weizmann institute in Israel, and in Shandong University in
China. Detailed testing of these chambers is performed at the Technion and at
the Tel-Aviv University. Two cosmic ray hodoscopes for testing the operation of
these detectors were built in Israel. In these hodoscopes the response of the
chambers to energetic cosmic ray muons is recorded and analyzed. The hodoscopes
measure the exact time and space location of the cosmic ray hit and read out
the chambers which are being tested to verify that they produce a corresponding
signal within the required time interval. The cosmic ray hodoscopes built at
the Technion and at the Tel Aviv University for the test of ATLAS TGCs are
described. The mechanical structure, readout electronics, data acquisition and
operating scheme are presented. Typical TGC test results are presented and
discussed
An Algebraic Approach for Decoding Spread Codes
In this paper we study spread codes: a family of constant-dimension codes for
random linear network coding. In other words, the codewords are full-rank
matrices of size (k x n) with entries in a finite field F_q. Spread codes are a
family of optimal codes with maximal minimum distance. We give a
minimum-distance decoding algorithm which requires O((n-k)k^3) operations over
an extension field F_{q^k}. Our algorithm is more efficient than the previous
ones in the literature, when the dimension k of the codewords is small with
respect to n. The decoding algorithm takes advantage of the algebraic structure
of the code, and it uses original results on minors of a matrix and on the
factorization of polynomials over finite fields
Precise Timing Adjustment for the ATLAS Level1 Endcap Muon Trigger System
The ATLAS level1 endcap muon trigger system consists of about 4000 Thin Gap Chambers (TGC) with 320,000 input electronics channels in order to find level1 trigger candidates for muons in both endcap regions. We had already adjusted channel-to-channel timing difference in overall TGC system with 1.2ns level, and found its consistency with the observation of beam halo events in the first proton circulation of LHC in September 2008. After that we have found some more correction factors to be incorporated with and eventually achieved timing adjustment in 0.9ns precision. In this presentation we also discuss an effective strategy for a parameter that can be adjusted using colliding beams
Streamlined Calibrations of the ATLAS Precision Muon Chambers for Initial LHC Running
The ATLAS Muon Spectrometer is designed to measure the momentum of muons with
a resolution of dp/p = 3% and 10% at 100 GeV and 1 TeV momentum respectively.
For this task, the spectrometer employs 355,000 Monitored Drift Tubes (MDTs)
arrayed in 1200 Chambers. Calibration (RT) functions convert drift time
measurements into tube-centered impact parameters for track segment
reconstruction. RT functions depend on MDT environmental parameters and so must
be appropriately calibrated for local chamber conditions. We report on the
creation and application of a gas monitor system based calibration program for
muon track reconstruction in the LHC startup phase.Comment: 25 pages, 21 figure
The First Result of Global Commissioning of the ATLAS Endcap Muon Trigger System in ATLAS Cavern
We report on the ATLAS commissioning run from the view point of the Thin Gap Chamber (TGC), which is the ATLAS end cap muon trigger detector. All the TGC sectors with on-detector electronics are going to be installed to the ATLAS cavern by the end of September 2007. To integrate all sub-detectors before the physics run starting from early 2008, the global commissioning run together with other sub-detectors has been performed from June 2007. We have evaluated the performance of the complete trigger chain of the TGC electronics and provide the trigger signal using cosmic-ray to the sub-systems in the global run environment
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