| 1. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Adler, SS, et al.
(författare)
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PHENIX on-line systems
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 560-592
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Carmody, C., et al.
(författare)
-
Ion-implanted In0.53Ga0.47As for ultrafast optoelectronic applications
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:22, s. 3913-3915
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Tidskriftsartikel (refereegranskat)abstract
- Undoped In0.53Ga0.47As epilayers were implanted with 2- MeV Fe+ ions at doses of 1x10(15) and 1x10(16) cm(-2) at room temperature and annealed at temperatures between 500 and 800 degreesC. Hall-effect measurements show that after annealing, layers with resistivities on the order of 10(5) Omega/square can be achieved. Carrier lifetimes as short as 300 fs are observed for samples annealed at 500 and 600 degreesC. For higher annealing temperatures, characteristic times of the optical response are on the order of a few picoseconds.
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| 4. |
- Carmody, C., et al.
(författare)
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Structural, electrical, and optical analysis of ion implanted semi-insulating InP
- 2004
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 95:2, s. 477-482
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Tidskriftsartikel (refereegranskat)abstract
- Semi-insulating InP was implanted with MeV P, As, Ga, and In ions, and the resulting evolution of structural properties with increased annealing temperature was analyzed using double crystal x-ray diffractometry and cross sectional transmission electron microscopy. The types of damage identified are correlated with scanning spreading resistance and scanning capacitance measurements, as well as with previously measured Hall effect and time resolved photoluminescence results. We have identified multiple layers of conductivity in the samples which occur due to the nonuniform damage profile of a single implant. Our structural studies have shown that the amount and type of damage caused by implantation does not scale with implant ion atomic mass.
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| 5. |
- Carmody, C., et al.
(författare)
-
Ultrafast carrier trapping and recombination in highly resistive ion implanted InP
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 94:2, s. 1074-1078
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Tidskriftsartikel (refereegranskat)abstract
- MeV P+ implanted and annealed p-InP, and Fe+ implanted and annealed semi-insulating InP have both been shown to produce the high resistivity, good mobility, and ultrafast optical response desired for ultrafast photodetectors. Hall effect measurements and time resolved photoluminescence were used to analyze the electrical and optical features of such implanted materials. Low temperature annealing was found to yield the fastest response times-130 fs for Fe+ implanted and 400 fs for P+ implanted InP, as well as resistivities of the order similar to10(6) Omega/square. It was found that the electrical activation of Fe-related centers, useful for achieving high resistivities in Fe+ implanted semi-insulating InP, was not fully realized at the annealing temperatures chosen to produce the fastest optical response. Implanting p-InP in the dose regime where type conversion occurs, and subsequent annealing at 500degreesC, produces high resistivities and ultrafast carrier trapping times that are only marginally dose dependent.
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| 6. |
- Li, Z-F, et al.
(författare)
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Determination of carrier-transfer length from side-wall quantum well to quantum wire by micro-photoluminescence scanning
- 2003
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Ingår i: Journal of Electronic Materials. - : Springer Science Business Media. - 0361-5235 .- 1543-186X. ; 32:8, s. 913-916
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Tidskriftsartikel (refereegranskat)abstract
- Micro-photoluminescence (mu-PL) line scanning across a single V-groove, GaAs/AlGaAs quantum wire (QWR) has been performed at room temperature, revealing a clear spatial-dependence of the PL. After fitting each PL spectrum by multi-Gaussian line shapes, intensity profiles of each PL component from confined structures have been obtained as functions of the scanning position. The PL quenching of a side-wall quantum well (SQWL) has been recognized in a certain area in the vicinity of the QWR and is interpreted by carrier transfer into the QWR within effective transfer length. By simulating the carrier-transfer process from SQWL to QWR as a convolution of a step function for carrier distribution and a Gaussian function for exciting laser irradiance, the effective transfer length of about 1.8+/-0.3 mum has, therefore, been concluded.
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| 7. |
- Adcox, K, et al.
(författare)
-
Construction and performance of the PHENIX pad chambers
- 2003
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 497:2-3, s. 263-293
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Tidskriftsartikel (refereegranskat)abstract
- We present the Pad Chamber detector system in the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The three station system provides space points along each track in the spectrometer arms at mid-rapidity and covers a total area of 88 m(2). Its main functions are to provide the track coordinate along the beam and to ensure reliable pattern recognition at very high particle multiplicity. A new concept for two dimensional wire chamber readout via its finely segmented cathode was developed. The full readout system, comprising 172 800 electronic channels, is described together with the challenging design of the chambers. The electronics, mounted on the outer chamber face, together with the chamber itself amounts to 1.2% of a radiation length. Results from cosmic ray tests, showing an average efficiency better than 99.5% for all chambers are presented. The experiences from the full scale operation in the first run are reported. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 8. |
- Kuznetsov, A. Y., et al.
(författare)
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Dynamic annealing in ion implanted SiC : Flux versus temperature dependence
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 94:11, s. 7112-7115
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Tidskriftsartikel (refereegranskat)abstract
- A strong influence of ion implantation flux on the accumulation of radiation damage, the so-called dose rate effect, is observed and systematically studied in SiC. 100 keV Si+ ions were implanted into bulk 4H-SiC wafers using different ion fluxes (1.9x10(10)-4.9x10(13) ions/cm(2) s) and keeping the implantation dose constant at 5x10(14) Si+/cm(2). The implants were performed both at room and elevated temperatures, up to 220 degreesC. Rutherford backscattering spectrometry in the channelling mode using 2 MeV He+ ions was employed to measure ion implantation damage profiles in the samples. For the flux interval used the most, pronounced dynamic annealing effect was detected at 80-160degreesC, having an activation energy of 1.3 eV. For example, at 100degreesC the amount of disordered Si atoms at the projected ion range is reduced by a factor of 4 by decreasing the ion flux from 4.9x10(13) to 1.9x10(10) ions/cm(2) s. The results are discussed in terms of migration and annihilation of intrinsic type defects for both the Si- and C-sublattices. In addition, two regions for the damage accumulation - at the surface and at the damage peak for 100 keV Si+ ions - are observed.
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| 9. |
- Leveque, P., et al.
(författare)
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Identification of hydrogen related defects in proton implanted float-zone silicon
- 2003
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Ingår i: European Physical Journal. - : EDP Sciences. - 1286-0042 .- 1286-0050. ; 23:1, s. 5-9
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen related defects in high purity n-type float zone silicon samples have been studied by means of Deep Level Transient Spectroscopy. They were introduced, as well as the characteristic vacancy-oxygen (VO) and divacancy (V-2) centers, by MeV proton implantation. Two hydrogen related defect levels were resolved at 0.32 eV and 0.45 eV below the conduction band edge (E-c). Careful annealing studies indicate strongly that a third hydrogen related level, overlapping with the singly negative charge state level of V-2, is also present in the implanted samples. The annealing behavior of the hydrogen related defects has been compared with literature data leading to a rather firm identification. The E-c-0.32 eV level originates from a VO center partly saturated with hydrogen (a VOH complex) while the E-c-0.45 eV level may be ascribed to a complex involving a monovacancy and a hydrogen atom ( a VH complex). The third hydrogen related defect is tentatively ascribed to a complex involving a hydrogen atom and a divacancy ( a V2H complex).
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| 10. |
- Leveque, Patrick, et al.
(författare)
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Vacancy and interstitial depth profiles in ion-implanted silicon.
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:2, s. 871-877
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Tidskriftsartikel (refereegranskat)abstract
- An experimental method of studying shifts between concentration-versus-depth profiles of vacancy- and interstitial-type defects in ion-implanted silicon is demonstrated. The concept is based on deep level transient spectroscopy measurements utilizing the filling pulse variation technique. The vacancy profile, represented by the vacancy-oxygen center, and the interstitial profile, represented by the interstitial carbon-substitutional carbon pair, are obtained at the same sample temperature by varying the duration of the filling pulse. The effect of the capture in the Debye tail has been extensively studied and taken into account. Thus, the two profiles can be recorded with a high relative depth resolution. Using low doses, point defects have been introduced in lightly doped float zone n-type silicon by implantation with 6.8 MeV boron ions and 680 keV and 1.3 MeV protons at room temperature. The effect of the angle of ion incidence has also been investigated. For all implantation conditions the peak of the interstitial profile is displaced towards larger depths compared to that of the vacancy profile. The amplitude of this displacement increases as the width of the initial point defect distribution increases. This behavior is explained by a simple model where the preferential forward momentum of recoiling silicon atoms and the highly efficient direct recombination of primary point defects are taken into account.
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