56010430
Use of an FPGA to identify electromagnetic clusters and isolated hadrons in the ATLAS level-1 calorimeter trigger
Abstract At the full LHC design luminosity of 10 34 cm −2 s −1 , there will be approximately 10 9 proton–proton interactions per second. The ATLAS level-1 trigger is required to have an acceptance factor of ∼10 −3 . The calorimeter trigger covers the region | η |⩽5.0, and φ =0 to 2 π . The distribution of transverse energy over the trigger phase space is analysed to identify candidates for electrons/photons, isolated hadrons, QCD jets and non-interacting particles. The Cluster Processor of the level-1 calorimeter trigger is designed to identify transverse energy clusters associated with the first two of these. The algorithms based on the trigger tower energies which have been designed to identify such clusters, are described here. The algorithms are evaluated using an FPGA. The reasons for the choice of the actual FPGA being used are given. The performance of the FPGA has been fully simulated, and the expected latency has been shown to be within the limits of the time allocated to the cluster trigger. These results, together with the results of measurements made with real data into a fully configured FPGA, are presented and discussed.
61376443
Prototype cluster processor module for the ATLAS level-1 calorimeter trigger
The Level-1 Calorimeter Trigger consists of a Preprocessor, a Cluster Processor (CP), and a Jet/Energy -sum Processor (JEP). The CP and JEP receive digitised triggertower data from the Preprocessor and produce trigger multiplicity and region-of-interest (RoI) information. The CP Modules (CPM) are designed to find isolated electron/photon and hadron/tau clusters in overlapping windows of trigger towers. Each pipelined CPM processes a total of 280 trigger towers of 8-bit length at a clock speed of 40 MHz. This huge I/O rate is achieved by serialising and multiplexing the input data. Large FPGA devices have been used to retrieve data and perform the cluster-finding algorithm. A full-specification prototype module has been built and tested, and first results will be presented.
111114972
Commissioning Experience with the ATLAS Level-1 Calorimeter Trigger System
The ATLAS Level-1 Calorimeter Trigger is one of the main elements of the first stage of event selection for the ATLAS experiment at the LHC. The input stage consists of a mixed analogue/digital component taking trigger sums from the ATLAS calorimeters. The trigger logic is performed in a digital, pipelined system with several stages of processing, largely based on FPGAs, which perform programmable algorithms in parallel with a fixed latency to process about 300 Gbyte/s of input data. The real-time output consists of counts of different types of physics objects and energy sums. The production of final modules started in 2006, and installation of these modules and the necessary infrastructure at ATLAS has been underway for some time, with the intention of having a full system in situ during 2007, before first collisions at the LHC. The first experiences of commissioning and running the full scale system will be presented, along with results from integration tests performed with the upstream calorimeters, and the downstream trigger and data flow systems.
27359669
The ATLAS level-1 calorimeter trigger architecture
The architecture of the ATLAS Level-1 Calorimeter Trigger system (L1Calo) is presented. Common approaches have been adopted for data distribution, result merging, readout, and slow control across the three different subsystems. A significant amount of common hardware is utilized, yielding substantial savings in cost, spares, and development effort. A custom, high-density backplane has been developed with data paths suitable for both the em//spl tau/ cluster processor (CP) and jet/energy-summation processor (JEP) subsystems. Common modules also provide interfaces to VME, CANbus and the LHC timing, trigger and control system (TTC). A common data merger module (CMM) uses field-programmable gate arrays (FPGAs) with multiple configurations for summing electron/photon and /spl tau//hadron cluster multiplicities, jet multiplicities, or total and missing transverse energy. The CMM performs both crate- and system-level merging. A common, FPGA-based readout driver (ROD) is used by all of the subsystems to send input, intermediate and output data to the data acquisition (DAQ) system, and region-of-interest (RoI) data to the level-2 triggers. Extensive use of FPGAs throughout the system makes the trigger flexible and upgradable, and several architectural choices have been made to reduce the number of intercrate links and make the hardware more robust.
122279281
The triumf low energy pion spectrometer and channel
Abstract A low energy pion spectrometer has been developed for use with the TRIUMF M13 pion channel. The combined channel and spectrometer resolution is presently 1.1. MeV at T = 50 MeV. This is limited by the amount of gas and detector material in the spectrometer in addition to the inherent resolution of the channel. Improvements to both the spectrometer and channel are discussed.
15246775
Prototype Readout Module for the ATLAS Level-1 Calorimeter Trigger Processors
The level-1 calorimeter trigger consists of three subsystems, namely the Preprocessor, electron/photon and tau/hadron Cluster Processor (CP), and Jet/Energy-sum Processor (JEP). The CP and JEP will receive digitised calorimeter trigger-tower data from the Preprocessor and will provide trigger multiplicity information to the Central Trigger Processor and region-of-interest (RoI) information for the level-2 trigger. It will also provide intermediate results to the data acquisition (DAQ) system for monitoring and diagnostic purposes. This paper will outline a readout system based on FPGA technology, providing a common solution for both DAQ readout and RoI readout for the CP and the JEP. Results of building a prototype readout driver (ROD) module will be presented, together with results of tests on its integration with level-2 and DAQ modules.
121317828
MEASUREMENT OF POLARIZATION IN K$sup +$p ELASTIC SCATTERING AT 1.37, 1.45, 1.71, AND 1.89 GeV/c AND PHASE-SHIFT ANALYSIS.
110416746
The Mark II silicon strip vertex detector and performance of a silicon detector telescope in the Mark II detector at the SLC
A silicon strip vertex detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). The performance of the individual modules and the stability and accuracy of their placement in the mechanical support are discussed. Top gain operational experience at the SLC, a telescope made of three silicon detector modules has been assembled and placed inside the Mark II. Results from the first data run of the SLC on the overall performance of the telescope, including backgrounds, charged particle tracking, and spatial resolution, are presented. >
122765043
A silicon strip vertex detector for the Mark II experiment at the SLAC linear collider
The design and status of a silicon strip vertex detector for the Mark II experiment at the SLAC Linear Collider are described.
121860857
The Mark II silicon strip vertex detector
Abstract A silicon strip vertex detector consisting of 36 modules has been built and operated in the Mark II solenoidal detector at the Stanford Linear Collider. The construction of the detector modules, their performance tests, the stability and accuracy of their placement, and the precision alignment of the complete device prior to and after installation are discussed. We also describe the operation of the vertex detector, and we discuss the measurement of impact parameters of charged particle tracks in conjunction with the Mark II wire drift chambers.
119786676
DESIGN STATUS OF THE CMS FORWARD PIXEL DETECTOR
Abstract The CMS experiment at the CERN LHC includes a pixel system for tracking and vertexing charged particles. This system consists of two parts: the central and the forward detectors. This paper describes the main features of the forward detectors, which are being built by a collaboration of physicists from the USA.