Search results for "Collider"

Precision luminosity measurements at LHCb

2014

Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves sig…

Update of the Binoth Les Houches Accord for a standard interface between Monte Carlo tools and one-loop programs

2014

We present an update of the Binoth Les Houches Accord (BLHA) to standardise the interface between Monte Carlo programs and codes providing one-loop matrix elements.

Prospects for quarkonium studies at the high-luminosity LHC

2020

Prospects for quarkonium-production studies accessible during the upcoming high-luminosity phases of the CERN Large Hadron Collider operation after 2021 are reviewed. Current experimental and theoretical open issues in the field are assessed together with the potential for future studies in quarkonium-related physics. This will be possible through the exploitation of the huge data samples to be collected in proton-proton, proton-nucleus and nucleus-nucleus collisions, both in the collider and fixed-target modes. Such investigations include, among others, those of: (i) J/psi and Upsilon produced in association with other hard particles; (ii) chi(c,b) and eta(c,b) down to small transverse mom…

Performance of ATLAS tracking detector

2012

The track and vertex reconstruction algorithms of the ATLAS Inner Detector have demonstrated excellent performance in the early data from the LHC. However, the rapidly increas- ing number of interactions per bunch crossing introduces new challenges both in computational aspects and physics performance. The combination of both silicon and gas based detectors provides high precision impact parameter and momentum measurement of charged particles, with high efficiency and small fake rate. Vertex reconstruction is used to identify with high efficiency the hard scattering process and to measure the amount of pile-up interactions, both aspects are cru- cial for many physics analyses. The performan…

An FPGA based Topological Processor Prototype for the ATLAS Level-1 Trigger Upgrade

2012

By 2014 the LHC will collide proton bunches at 14TeV with an increased instantaneous luminosity up to 3·10³⁴cm⁻²s⁻¹. The resulting higher event rate will challenge the existing ATLAS trigger system. A reduction on the trigger rate can be achieved by selecting interesting channels based on their expected decay topology and thus reducing background. This will be achieved by introducing of a new FPGA based module in the Level-1 trigger: the Topological Processor L1Topo. With L1Topo it will be possible for the first time to concentrate detailed information from the entire calorimeters and the muon detector into a single module. L1Topo will receive a total aggregate bandwidth of 1Tb/s. The data …

The ATLAS Level-1 Calorimeter Trigger: PreProcessor implementation and performance

2012

The PreProcessor system of the ATLAS Level-1 Calorimeter Trigger (L1Calo) receives about 7200 analogue signals from the electromagnetic and hadronic components of the calorimetric detector system. Lateral division results in cells which are pre-summed to so-called Trigger Towers of size 0.1 × 0.1 along azimuth (phi) and pseudorapidity (η). The received calorimeter signals represent deposits of transverse energy. The system consists of 124 individual PreProcessor modules that digitise the input signals for each LHC collision, and provide energy and timing information to the digital processors of the L1Calo system, which identify physics objects forming much of the basis for the full ATLAS fi…

The Optical Multiplexer Board for the ATLAS Hadronic Tile Calorimeter

2007

This paper presents the architecture and the status of the optical multiplexer board (OMB) for the ATLAS/LHC tile hadronic calorimeter (TileCal). This board will analyze the front-end data CRC to prevent bit and burst errors produced by radiation. Besides, due to its position within the data acquisition chain it will be used to emulate front-end data for tests. The first two prototypes of the final OMB 9U version have been produced at CERN. Detailed design issues and manufacturing features of these prototypes are described. These prototypes are being validated while firmware developments are being implemented in the programmable devices of the board.

Accelerating Radioactive Ion Beams With REX-ISOLDE

2003

The post accelerator REX‐ISOLDE is installed at the ISOLDE facility at CERN, where a broad variety of radioactive ions can be addressed. Since the end of 2001 beams at the final energy of 2.2 MeV/u are available. REX‐ISOLDE uses a unique system of beam bunching and charge breeding. First a Penning trap accumulates and bunches the ions, which are delivered as a quasi‐continuous beam from the ISOLDE target‐ion‐source, and then an electron beam ion source (EBIS) charge‐breeds them to a mass‐to‐charge ratio below 4.5. This enables a very compact design for the following LINAC, consisting of a 4 rod RFQ, an IH structure and three 7‐gap‐resonators. The later ones allow a variation of the final en…

Readout system of the ALICE Fast Interaction Trigger

2020

MuPix and ATLASPix -- Architectures and Results

2020

High Voltage Monolithic Active Pixel Sensors (HV-MAPS) are based on a commercial High Voltage CMOS process and collect charge by drift inside a reversely biased diode. HV-MAPS represent a promising technology for future pixel tracking detectors. Two recent developments are presented. The MuPix has a continuous readout and is being developed for the Mu3e experiment whereas the ATLASPix is being developed for LHC applications with a triggered readout. Both variants have a fully monolithic design including state machines, clock circuitries and serial drivers. Several prototypes and design variants were characterised in the lab and in testbeam campaigns to measure efficiencies, noise, time reso…