The ALICE experiment at LHC: physics prospects and detector design

ALICE (A Large Ion Collider Experiment)is a dedicated detector designed to exploit the unique physics opportunities which will be offered by nucleus-nucleus collisions at the LHC. At the LHC,it will be possible to explore a radically new regime of matter, stepping up by a large factor in both volume and energy density from the nuclear interactions studied at the SpS and at RHIC. Thanks to the huge number of secondaries produced, it will be possible to measure most of the relevant variables on an event-by-event basis. The LHC energy and luminosity will allow the full spectroscopy of the Y family and of D and B mesons. ALICE is conceived as a genera -purpose detector, in which most of the hadrons, leptons and photons produced in the interaction can be measured and identified. The baseline design consists of a central ( |n| < 0 .9) detector covering the full azimuth and a forward (2 .4 < n < 4) muon arm, complemented by a forward magnetic spectrometer to study vector meson production, a multiplicity detector covering the forward rapidity region (up to |n| = 4.5) and a zero degree calorimeter. The central detector will be embedded in large magnet with a weak field of 0.2T, and will consist of a high-resolution inner tracking system, a cylindrical time projection chamber, particle identification arrays (time of flight and ring imaging cerenkov detectors), a transition radiation detector for electron identification and a single-arm electromagnetic calorimeter

Beam test results of the irradiated Silicon Drift Detector for ALICE

The Silicon Drift Detectors will equip two of the six cylindrical layers of high precision position sensitive detectors in the ITS of the ALICE experiment at LHC. In this paper we report the beam test results of a SDD irradiated with 1 GeV electrons. The aim of this test was to verify the radiation tolerance of the device under an electron fluence equivalent to twice particle fluence expected during 10 years of ALICE operation.Comment: 6 pages,6 figures, to appear in the proceedings of International Workshop In high Multiplicity Environments (TIME'05), 3-7 October 2005, Zurich,Switzerlan

Strongly Enhanced Current Densities in Superconducting Coated Conductors of YBa2Cu3O7-x + BaZrO3

There are numerous potential applications for superconducting tapes, based on YBa2Cu3O7-x (YBCO) films coated onto metallic substrates. A long established goal of more than 15 years has been to understand the magnetic flux pinning mechanisms which allow films to maintain high current densities out to high magnetic fields. In fact, films carry 1-2 orders of magnitude higher current densities than any other form of the material. For this reason, the idea of further improving pinning has received little attention. Now that commercialisation of conductors is much closer, for both better performance and lower fabrication costs, an important goal is to achieve enhanced pinning in a practical way. In this work, we demonstrate a simple and industrially scaleable route which yields a 1.5 to 5-fold improvement in the in-field current densities of already-high-quality conductors

Characteristics of the ALICE Silicon Drift Detector

A Silicon Drift Detector (SDD) with an active area of 7.0 x 7.5 cm2 has been designed, produced and tested for the ALICE Inner Tracking System. The development of the SDD has been focussed on the capability of the detector to work without an external support to the integrated high voltage divider. Severalfeatures have been implemented in the design in order to increase the robustness and the long-term electrical stability of the detector. One of the prototypes has been tested in a pion beam at the CERN SPS. Preliminary results on the position resolution are given

Radiation damage of silicon strip detectors in the NA50 experiment

Abstract During operation of the multiplicity detector in the NA50 experiment the single sided AC-coupled p-on-n silicon strip detectors were exposed to charged particle fluences up to 10 14 eq n/cm 2 and ionising doses up to 20 Mrad, with a very non-uniform radiation spatial distribution. Radiation effects in the detectors observed during the '96 lead ion run as well as results of the post-run measurements are presented in this paper

Analysis of radiation effects on silicon strip detectors in the NA50 experiment

Abstract During the operation of the Multiplicity Detector in the NA50 experiment the single sided AC-coupled p-on-n silicon strip detectors were exposed to charged particle fluences resulting in an equivalent 1 MeV neutron fluence up to 10 14 eq. n/cm 2 and a total ionising dose up to 20 Mrad, with a very non-uniform radiation spatial distribution. In this paper detailed analysis of radiation effects observed on the detectors during the 1996 lead ion run as well as results of measurements performed after the run are presented

Correction of Dopant Concentration Fluctuation Effects in Silicon Drift Detectors

Dopant fluctuations in silicon wafers are responsible for systematic errors in the determination of the particle crossing point in silicon drift detectors. In this paper, we report on the first large scale measurement of this effect by means of a particle beam. A significant improvement of the anodic resolution has been obtained by correcting for these systematic deviations

Recent results from beam tests of large area silicon drift detectors

Silicon drift detectors with an active area of 7.0 × 7.5 cm2 will equip the two middle layers of the Inner Tracking System of the ALICE experiment. The performance of several prototypes was studied during beam tests carried out at the CERN SPS facility. The results of the beam test data analysis are discussed in this paper

The ALICE Silicon Drift Detector System

The project of the two Silicon Drift Detector layers of the ALICE Inner Tracking System is reviewed. Recent results obtained from beam tests are presented

传统视阈与现代蜕变——地方戏曲保护中的学术理想

Silicon drift detectors (SDDs) are well suited to high-energy physics experiments with relatively low event rates. In particular SDDs will be used for the two intermediate layers of the Inner Tracking System of the ALICE experiment. Beam test results of linear SDD prototypes have shown a resolution of 40*30 mu m/sup 2/ and a cluster finding efficiency of essentially 100% with E=600 V/cm. (6 refs)