Heavy Ion Physics at the LHC

The first Pb-Pb collisions at the LHC are little more than a year away. This paper discusses some of the exciting measurements which the experiments will be able to perform in the very first run, even with modest luminosity, and gives a very short overview of some of the most interesting ones attainable with more extended runs. The dedicated Heavy-Ion experiment ALICE, but also ATLAS and CMS, experiments optimized for p-p collisions, are ready and eager to make best use of the nuclear beams in the LHC as soon as they will be available. The main specificities of the three detectors for Heavy-Ion collisions will also be briefly addressed in this paper. I will try to show that already the first results obtainable with Heavy-Ion beams at the LHC will qualify it as a discovery machine, capable to provide fundamental new insight to our knowledge of high-density QCD matter.Comment: Invited talk at the Hadron Collider Physics Symposium (HCP2008), Galena, Illinois, USA, May 27-31, 2008; 9 pages, .docx fil

Status of the ALICE Experiment

ALICE (A Large Ion Collider Experiment), the dedicated detector designed to study nucleus-nucleus collisions at the LHC, is developing rapidly. While the experimental area is being cleared of the last elements of the L3 detector, who stopped datataking at the end of 2000, the ALICE collaboration is at work for the first steps of the installation of the detector, namely the refurbishing work on the L3 magnet and the adaptation of the infrastructure. In the meantime, in the 77 laboratories of the Collaboration, the work of preparation of the detectors is changing gear: the R&D is completed on almost all elements, with some notable advances in innovative technologies, and the major detectors components have entered the production phase. Moreover the TRD, a major new detector designed to expand the ALICE capability to identify electrons, has reached the Technical Design Report stage and is now being discussed by the LHCC. The status of our understanding of the ALICE Physics potential is described in other papers in these proceedings [4, 5, 6], so I will concentrate here on a brief description of the ALICE detectors, with mention of the most recent results achieved

Status and prospects of experiments with ultrarelativistic nuclear beams

Experiments with ultra-relativistic nuclear beams have been carried out since the early eighties, seeking a detailed understanding of Nuclear Matter at extreme temperatures and densities. In such conditions QCD predicts that quarks and gluons are no longer bound in hadrons, and form a so-called Quark-Gluon- Plasma (QGP), a state in which the Universe should have been a few microseconds after the Big Bang. This experimental programme has enjoyed enormous success, and the number of scientists involved has grown continuously through the years. In the meantime, while the experimental and theoretical tools to collect and understand the data were constantly improving, so has done the energy of the beams available for experiments. From the 1 GeV per nucleon pair of the Bevalac at Berkeley, accelerators have increased in energy to the AGS at BNL (few GeV) to the SPS at CERN (almost 20 GeV), to the Relativistic Heavy Ion Collider at BNL (200GeV). Sometime during 2010 the LHC will bring in another major step, going to 5500GeV. During these years an enormous path has been covered, and experimenters have learnt how to deal with events of unprecedented complexity, with first hundreds, then thousands of particles produced. The phase diagram of strongly interacting matter has been populated of measured points, and strategies have been developed to investigate the nature and dynamical evolution of the high-density system generated. Physicists are pursuing a new generation of experiments which will allow a quantum step in our understanding of the QGP but also a more detailed exploration of the phase diagram and in particular of the phase transition. In this paper, I will briefly review our present understanding of the physics with ultrarelativistic nuclear beams, and then outline the perspectives of the experiments for the coming years

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

Conference Summary of QNP2018

This report is the summary of the Eighth International Conference on Quarks and Nuclear Physics (QNP2018). Hadron and nuclear physics is the field to investigate high-density quantum many-body systems bound by strong interactions. It is intended to clarify matter generation of universe and properties of quark-hadron many-body systems. The QNP is an international conference which covers a wide range of hadron and nuclear physics, including quark and gluon structure of hadrons, hadron spectroscopy, hadron interactions and nuclear structure, hot and cold dense matter, and experimental facilities. First, I introduce the current status of the hadron and nuclear physics field related to this conference. Next, the organization of the conference is explained, and a brief overview of major recent developments is discussed by selecting topics from discussions at the plenary sessions. They include rapidly-developing field of gravitational waves and nuclear physics, hadron interactions and nuclear structure with strangeness, lattice QCD, hadron spectroscopy, nucleon structure, heavy-ion physics, hadrons in nuclear medium, and experimental facilities of EIC, GSI-FAIR, JLab, J-PARC, Super-KEKB, and others. Nuclear physics is at a fortunate time to push various projects at these facilities. However, we should note that the projects need to be developed together with related studies in other fields such as gravitational physics, astrophysics, condensed-matter physics, particle physics, and fundamental quantum physics.Comment: 10 pages, LaTeX, 1 style file, 3 figure files, Proceedings of Eighth International Conference on Quarks and Nuclear Physics (QNP2018), November 13-17, 2018, Tsukuba, Japa

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

Characterisation of silicon strip detectors with a binary readout chip for X-ray imaging

In this paper we describe the development of a multichannel readout system for X-ray measurements using silicon strip detectors. The developed system is based on a binary readout architecture and optimised for detection of X-rays of energies in the range 6}30 keV. The critical component of the system is the 32-channel front-end chip, RX32N, which has been optimised for low noise performance, small channel to channel variation and high counting rate operation. The performance of the chip is demonstrated by measurements of complex X-ray spectra using silicon strip and pad detectors. The obtained results allow to use the system at room temperature with the detection threshold in the range from 500 to 10 000 electrons, which is enough in many crystallographic and medical imaging applications. ( 2000 Elsevier Scienc

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

Recent Developments on the Silicon Drift Detector readout scheme for the ALICE Inner Tracking System

Proposal of abstract for LEB99, Snowmass, Colorado, 20-24 September 1999Recent developments of the Silicon Drift Detector (SDD) readout system for the ALICE Experiment are presented. The foreseen readout system is based on 2 main units. The first unit consists of a low noise preamplifier, an analog memory which continuously samples the amplifier output, an A/D converter and a digital memory. When the trigger signal validates the analog data, the ADCs convert the samples into a digital form and store them into the digital memory. The second unit performs the zero suppression/data compression operations. In this paper the status of the design is presented, together with the test results of the A/D converter, the multi-event buffer and the compression unit prototype.Summary:In the Inner Tracker System (ITS) of the ALICE experiment the third and the fourth layer of the detectors are SDDs. These detectors provide the measurement of both the energy deposition and the bi-dimensional position of the track. In terms of readout an SDD can be viewed as a matrix, where the rows are the detector anodes and the columns are the samples to be read during the drift time; therefore, a very large amount of data has to be amplified, converted in digital form and preprocessed in order to avoid the storage of non-significatn data.Since the electron mobility is a strong temperature function, detector temperature has to be kept constant; on the other hand, it is not possible to use very efficient cooling systems because the amount of material in this area is very limited, so the power budget for the electronic readout is very low (less than 6 mW/anode).The simplest solution would be to send the analog signals outside the sensitive area immediately after a preamplification; unfortunately, the ratio between the number of channels (around 200 000) and the space available is so high that the simple solution of sending all the SDD anodes output outside teh detector zone after a low-noise amplification is not practically manageable.Abstract:The adopted solution is based on three main units:(i) A front-end chip that performs low noise amplification, fast analog storage and A/D conversion(ii) A multi-event digital buffer for data derandomization(iii) A data compression/zero suppression and system control boardThe first two units are distributed on the ladders near the detectors and have stringent power and space requirements, while the third unit is placed at both ends of the ladders and in boxes placed on both ends of the TPC detector.The first unit is the most critical part of the system. It works as follows: the detector signals are continuously amplified, sampled and stored in the analog memory with a frequency of 40 MSamples/s The L0d trigger signal stops the write operation, while the L1 trigger signal starts the conversion phase. This phase will continue until the event data are stored in the event buffer if the L2y confirm trigger signal is received, or rejected if the L2n abort signal will be issued by the trigger system.Prototypes of the three parts have been designed and tested while the full chip is currently under design. Tests of the A/D converter will be presented.The multi-event buffer purpose is to de-randomize the even data in order to reduce the transmission speed. Preliminary tests of the first prototype will be presented.The board placed at the end of the ladders performs various functions. It reduces the amount of data through various cascaded algorithms with variable parameters and transmits the data to the SIU board. It also controls the test and slow control system for the ladder circuitry. Tests of the FPGA-based prototypes will be presented.Special care has been taken for the test problem. The ASICs designed are provided of a test control port based on teh IEEE 1149.1 JTAG standard. The same protocol is used for downloading configuration information