I. Kotov

Development of large linear silicon drift detectors for the STAR experiment at RHIC

Abstract Large area linear Silicon Drift Detectors (SDD) are being developed for high energy and relativistic heavy ion collider experiments. SDDs have been proposed for the inner tracking detector in the STAR experiment at the BNL relativistic heavy ion collider to become operational in 1999. The Silicon Vertex Tracker (SVT) will consist of a three layer barrel structure composed of 216 individual detectors, each 6.3 × 6.3 cm 2 . Prototypes, including one-way drift detectors (4.5 × 4.5 cm 2 ) and bi-directional drift detectors (6 × 6 cm 2 ) have been manufactured,and their properties have been studied. Design considerations, as well as test results, are presented in this article. Recent work has focused on minimizing the inactive guard structure area in order to optimize tracking efficiency. Particular attention is given to discussion of parameters that are sensitive to the reduced guard structure area, such as leakage current, maximum voltage and drift non-linearities.

Silicon drift detectors for the STAR/SVT experiment at RHIC

Large area linear Silicon Drift Detectors (SDD) were developed to be used in the Silicon Vertex Tracker (SVT) of the STAR experiment at the BNL relativistic heavy ion collider (RHIC). The SDD is in its final design and has been submitted for large scale production. Test results show that the detector exhibits excellent position resolution and low noise. A special characterization procedure was developed to test detector wafers in order to select good detectors for the SVT. Recently, 15 STAR/SVT SDDs were assembled as a tracking device in a BNL-AGS heavy ion experiment (E896). It is the first tracking application of these detectors and their corresponding front-end electronics in an experimental environment. Preliminary results indicating good detector performance are shown and discussed in this paper.

An update on the strangeness production measurements and H0 di-baryon search as performed by the AGS experiment 896

E896 was designed to search for the predicted short-lived six-quark H0 di-baryon. The goal is to enhance the existing knowledge by extending the search into regions of shorter lifetimes (approximately half that of the lambda) and via exploring a new creation channel, that of the coalescence of two lambdas. Two main tracking chambers are used, a distributed drift chamber positioned to measure low-pt and high-rapidity neutral particle decay products and a silicon drift detector array which measures particle production at mid-rapidity. Both detectors are also investigating lambda polarization, over their respective coverages, for Au-Au collisions at 11.3 GeV/nucleon. The current status of the H0 di-baryon search and preliminary results of the strange particle production and polarization measurements will be presented.

Electron injection in semiconductor drift detectors

Abstract We report on the injection of electrons from surface structures of Silicon Drift Detectors into the bulk of the detector for calibration purposes. Also, with these injector structures, detection of magnetic field components perpendicular to the detector’s surface is possible. Implanted line and dot injectors along with MOS injectors are discussed. Studies of lateral uniformity of injection, biasing of injectors to facilitate injection and dot injection are discussed.

Transport properties of electrons in silicon drift detectors measured in large magnetic fields

Abstract A 45 × 45 mm rectangular n-type Silicon Drift Detector was studied in magnetic fields ranging from 0 to 4.7 T and for drift fields from 200 to 380 V/cm. Transport properties of electrons in silicon (Hall mobility, drift mobility and magnetoresistance) were determined by pulsing the detector with a Nd:YAG laser at different drift lengths and measuring both the transverse deflections of the signal and the increases in drift time versus an applied magnetic field. The width of the signal in both the drift and anode direction increased with magnetic field. The magnetic field was aligned parallel and normal to the drift direction. The detector was found to operate well for conditions expected in future experiments at the RHIC collider and experiment E896 at Brookhaven National Laboratory.

Operation and calibration of the Silicon Drift Detectors of the ALICE experiment during the 2008 cosmic ray data taking period

The calibration and performance of the Silicon Drift Detector of the ALICE experiment during the 2008 cosmic ray run will be presented. In particular the procedures to monitor the running parameters (baselines, noise, drift speed) are detailed. Other relevant parameters (SOP delay, time-zero, charge calibration) were also determined.

The silicon drift vertex detector for the STAR experiment at RHIC

Abstract The current status of the STAR Silicon Vertex Tracker (SVT) is presented. The performance of the Silicon Drift Detectors (SDD) is discussed. Results for a recent 15 layer SDD tracker which prototypes all components of the SVT are presented. The enhanced physics capabilities of the STAR detector due to the addition of the SVT are addressed.

Probe station for testing of ALICE silicon drift detectors

AbstractLarge area, 7:25cm 8:76cm silicon drift detectors have beendeveloped and are inproduction for the ALICEexperiment at LHC. An active area of the detector of more than 50cm 2 imposes high demands on the quality ofprocessingandrawmaterial.Automatedtestingprocedureshavebeendevelopedtotestdetectorsbeforemountingthemontheladders.ProbestationsforALICESDDtestingweredesignedandbuiltatINFN,TriesteandOhioStateUniversity(OSU).Testingprocedures,detectorselectioncriteriaandsomedetailsoftheOSUprobestationdesignarediscussed.r 2003ElsevierB.V.Allrightsreserved. PACS: 29.40.WkKeywords: Probestation;Silicondriftdetectors 0. IntroductionThe inner tracking system (ITS) [1] of theALICE experiment surrounds the interactionregionwithsixconcentriccylindricallayers.TwoofthemareSiliconDriftDetector(SDD)layers.TheinnerSDDlayeriscomposedof14ladders,eachholdingsixdetectors.TheouterSDDlayerismade of 22 ladders supporting eight detectorseach.Intotal260highqualitySDDsareneeded.In SDDs fabricated on n-type silicon, theelectronscreatedbyanionizingparticleinafullydepleted bulk of silicon drift toward the anodes.Charge sharing between anodes provides onecoordinateofeach particle crossingthedetector.Theothercoordinateisdeterminedfromthedrifttime measurement. Deposited energy can beobtained from the signal waveform. Beam testmeasurements and simulations of the ALICESDDsshowthattheachievablepositionresolutionalong the drift is B30mm [2]. Critical factors toachievesucharesolutionarelownoiseandoverallgoodqualityofthedetectors.DC characteristics of the detectors such asanode leakage currents and voltage distributionacrossthecathodesprovidesufficientinformation

First results from the H0 di-baryon search and hyperon production measurements by the AGS Experiment 896.

Abstract The AGS Experiment 896 was designed to study strangeness production in Au—Au collisions at 11.6A GeV/c, in particular the formation of a six-quark di-baryon the H 0 . Heavy ion collisions provide favorable conditions for the H 0 formation either via coalescence of two Λ particles (owing to the large Λ production cross section) or direct production from the possible formation of a quark-gluon plasma. E896 also measured strange meson and baryon distributions from mid-rapidity. Preliminary results from this experiment are presented as well as details of the expected sensitivity for the H 0 search.

Double particle resolution in STAR silicon drift detectors

The inner tracking detector of the STAR experiment at the BNL Relativistic Heavy Ion Collider will consist of a three layer barrel structure of 216 silicon drift detectors. Calculations of the two-hit resolution achievable for these detectors are presented in this article. The effects on two-hit resolution of the electronics response function, frequency of signal digitization and noise level are discussed.