42 research outputs found
Development and commissioning of the ALICE pixel detector control system
The Silicon Pixel Detector (SPD) is the innermost detector of the ALICE Inner Tracking System and the closest one to the interaction point. In order to operate the detector in a safe way, a control system was developed in the framework of PVSS which allows to monitor and control a large number of parameters such as temperatures, currents, voltages, etc. The control system of the SPD implements interlock features to protect the detector against overheating and prevents operating it in case of malfunctions. The nearly 50,000 parameters required to fully configure the detector are stored in a database which employs automatic configuration versions after a new calibration run has been carried out. Several user interface panels were developed to allow experts and non-expert shifters to operate the detector in an easy and safe way. This contribution provides an overview of the SPD control system
Calibration of the Prompt L0 Trigger of the Silicon Pixel Detector for the ALICE Experiment
The ALICE Silicon Pixel Detector (SPD) is the innermost detector of the ALICE experiment at LHC. It includes 1200 front-end chips, with a total of ~107 pixel channels. The pixel size is 50 x 425 μm2. Each front-end chip transmits a Fast-OR signal upon registration of at least one hit in its pixel matrix. The signals are extracted every 100 ns and processed by the Pixel Trigger (PIT) system, to generate trigger primitives. Results are then sent within a latency of 800 ns to the Central Trigger Processor (CTP) to be included in the first Level 0 trigger decision. This paper describes the commissioning of the PIT, the tuning procedure of the front-end chips Fast-OR circuit, and the results of operation with cosmic muons and in tests with LHC beam
The ALICE Silicon Pixel Detector Control system and online calibration tools
The ALICE Silicon Pixel Detector (SPD) contains nearly 107 hybrid pixel cells. The operation of the SPD requires online control and monitoring of some 2000 parameters and » 50000DACs. Information for each channel is stored in a configuration database. Timing and data management (» 6GB of raw data each calibration) are critical issues. An overview of the SPD electronics read out chain and of the detector control system is given with a detailed description of the front-end controls and the calibration strategy. The status of commissioning and a preliminary evaluation of detector performance are presented
The ALICE silicon pixel detector read-out electronics
The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the ALICE inner tracker system. The SPD contains 10 million pixels segmented in 120 detector modules (half staves), which are connected to the offdetector electronics with bidirectional optical links. Raw data from the on-detector electronics are sent to 20 FPGA-based processor cards (Routers) each carrying three 2-channel linkreceiver daughter-cards. The routers process the data and send them to the ALICE DAQ system via the ALICE detector data link (DDL). The SPD control, configuration and data monitoring is performed via the VME interface of the routers. This paper describes the detector readout and control via the off-detector electronics
Performance of ALICE pixel prototypes in high energy beams
The two innermost layers of the ALICE inner tracking system are instrumented
with silicon pixel detectors. Single chip assembly prototypes of the ALICE
pixels have been tested in high energy particle beams at the CERN SPS.
Detection efficiency and spatial precision have been studied as a function of
the threshold and the track incidence angle. The experimental method, data
analysis and main results are presented.Comment: 10 pages, 9 figures, contribution to PIX2005 Workshop, Bonn
(Germany), 5-8 September 200
Beam Test Performance and Simulation of Prototypes for the ALICE Silicon Pixel Detector
The silicon pixel detector (SPD) of the ALICE experiment in preparation at
the Large Hadron Collider (LHC) at CERN is designed to provide the precise
vertex reconstruction needed for measuring heavy flavor production in heavy ion
collisions at very high energies and high multiplicity. The SPD forms the
innermost part of the Inner Tracking System (ITS) which also includes silicon
drift and silicon strip detectors. Single assembly prototypes of the ALICE SPD
have been tested at the CERN SPS using high energy proton/pion beams in 2002
and 2003. We report on the experimental determination of the spatial precision.
We also report on the first combined beam test with prototypes of the other ITS
silicon detector technologies at the CERN SPS in November 2004. The issue of
SPD simulation is briefly discussed.Comment: 4 pages, 5 figures, prepared for proceedings of 7th International
Position Sensitive Detectors Conference, Liverpool, Sept. 200
The ALICE Silicon Pixel Detector System (SPD)
The ALICE silicon pixel detector (SPD) comprises the two innermost layers of the ALICE inner tracker system. The SPD includes 120 detector modules (half-staves) each consisting of 10 ALICE pixel chips bump bonded to two silicon sensors and one multi-chip read-out module. Each pixel chip contains 8192 active cells, so that the total number of pixel cells in the SPD is ≈ 107. The on-detector read-out is based on a multi-chip-module containing 4 ASICs and an optical transceiver module. The constraints on material budget and detector module dimensions are very demanding
The ALICE Silicon Pixel Detector: readiness for the first proton beam
The Silicon Pixel Detector (SPD) is the innermost element of the ALICE Inner Tracking
System (ITS). The SPD consists of two barrel layers of hybrid silicon pixels surrounding the
beam pipe with a total of 48 10^7 pixel cells. The SPD features a very low material budget, a 99.9%
efficient bidimensional digital response, a 12 micron spatial precision in the bending plane (rf ) and a
prompt signal as input to the L0 trigger. The SPD commissioning in the ALICE experimental area
is well advanced and it includes calibration runs with internal pulse and cosmic ray runs. In this
contribution the commissioning of the SPD is reviewed and the first results from runs with cosmic
rays and circulating proton beams are presented
Transverse momentum spectra of charged particles in proton-proton collisions at GeV with ALICE at the LHC
The inclusive charged particle transverse momentum distribution is measured
in proton-proton collisions at GeV at the LHC using the ALICE
detector. The measurement is performed in the central pseudorapidity region
over the transverse momentum range GeV/.
The correlation between transverse momentum and particle multiplicity is also
studied. Results are presented for inelastic (INEL) and non-single-diffractive
(NSD) events. The average transverse momentum for is (stat.) (syst.) GeV/ and
\left_{\rm NSD}=0.489\pm0.001 (stat.) (syst.)
GeV/, respectively. The data exhibit a slightly larger than measurements in wider pseudorapidity intervals. The results are
compared to simulations with the Monte Carlo event generators PYTHIA and
PHOJET.Comment: 20 pages, 8 figures, 2 tables, published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/390