Search results for "ELECTRONICS"
showing 10 items of 4340 documents
THE FASTBUS READ-OUT SYSTEM FOR THE ALEPH TIME PROJECTION CHAMBER
1989
The readout system for the Aleph central tracking detector, a large time projection chamber (TPC), consists of more than 100 FASTBUS crates with approximately 1000 FASTBUS modules. The detector and its associated electronics are briefly presented, followed by a more detailed description of the readout and control system. The discussion covers the sector readout, electronics calibration, front-end data acquisition, data pipelining, and service request handling. Experiences with the system are discussed. >
The read-out processors of the Aleph time projection chamber and their performance
1990
The Aleph detector is installed on the LEP electron-positron storage ring. Its central tracking detector, a time projection chamber (TPC), has about 50000 channels of sampling electronics. The digitized signals are processed by 72 double-width Fastbus modules built around an MC 68020 processor. The time projection processor is described, and the solutions, both hardware and software, adopted to run and manage such a complex system in a Fastbus-VAX environment are discussed. Practical experience with the system is reported. >
A digital approach for real time high-rate high-resolution radiation measurements
2014
Abstract Modern spectrometers are currently developed by using digital pulse processing (DPP) systems, showing several advantages over traditional analog electronics. The aim of this work is to present digital strategies, in a time domain, for the development of real time high-rate high-resolution spectrometers. We propose a digital method, based on the single delay line (SDL) shaping technique, able to perform multi-parameter analysis with high performance even at high photon counting rates. A robust pulse shape and height analysis (PSHA), applied on single isolated time windows of the detector output waveforms, is presented. The potentialities of the proposed strategy are highlighted thro…
Time response of avalanche photodiodes as a function of the internal gain
1998
Abstract Using a red LED and a blue laser as a light source, time response of avalanche photodiodes and Metal-Resistive Silicon (MRS) layer avalanche photodiodes [1] has been measured. A strong dependence of the time resolution on the internal gain has been observed. The obtained results show that the increase of the internal gain improves the time resolution. However, there exists a critical value for the internal gain. Beyond this value a deterioration of the time resolution is observed.
Commissioning the ATLAS silicon microstrip tracker
2009
Abstract The completed SemiConductor Tracker (SCT) has been installed inside ATLAS. Quick tests were performed last year to verify the connectivity of the electrical and optical services. Problems observed with the heaters for the evaporative cooling system have been resolved. This has enabled extended operation of the full detector under realistic conditions. Calibration data has been taken and analyzed to determine the noise performance of the system. In addition, extensive commissioning with cosmic ray events has started. The cosmic muon data has been used to align the detector, to check the timing of the front-end electronics as well as to measure the hit efficiency of modules. The curr…
Time-dependent electric field in Al/CdTe/Pt detectors
2015
Abstract Al/CdTe/Pt detectors are very attractive devices for high-resolution X-ray spectroscopy, even though they suffer from bias-induced time instability (polarization). Polarization phenomena cause a progressive time-degradation of the spectroscopic performance of the detectors, due to hole trapping and detrapping from deep acceptor levels that directly control the electric field distribution. In this work we present experimental investigations on the electric field profile of planar Al/CdTe/Pt detectors by means of Pockels effect measurements. The time/temperature dependence of the electric field was investigated in a long time window (up to 10 h) and the correlation with the reverse c…
Positron implantation profiles in layered samples
2009
The paper presents theoretical and experimental studies of the positron implantation profiles in layered samples. The Monte Carlo simulations performed using the GEANT4 toolkit reveal accumulation of positrons in the denser layer embedded between two less dense layers. That effect is significant not only for low energy positrons at slow monoenergetic positron beams but also for high energy positrons which are emitted from radioactive nuclei in conventional experiments. Measurements of the positron implantation profile into the samples which consist of silver and aluminium foils of different thickness show profile features which correspond well with those simulated by the GEANT4 toolkit for …
Improving the Performance of Quasi-Hemispherical CdZnTe Detectors Using Infrared Stimulation
2012
The influence of monochromatic optical stimulation with wavelengths from 400 to 1100 nm on the characteristics of CdZnTe quasi-hemispherical detectors was studied. It was found that illumination with infrared (IR) light with wavelengths of 870-900 nm close to the absorption edge of the CdZnTe significantly improves the performance of the detector at room temperature. Improvement can be achieved with low-intensity IR illumination at 1-300 μW depending on the chosen wavelength of illumination. Higher intensity illumination was observed to lead to the degradation of the detector's spectrometric characteristics. IR radiation was noted to influence the detector's sensitivity, changing the equili…
Pre-production validation of the ATLAS level-1 calorimeter trigger system
2006
The Level-1 Calorimeter Trigger is a major part of the first stage of event selection for the ATLAS experiment at the LHC. It is 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 trigger objects and energy sums. Prototypes of all module types have been undergoing intensive testing before final production during 2005. Verification of their correct operation has been performed stand-alone and in the ATLAS test-beam at CERN. Results from these investigations will be presented, along …
Upgrade Analog Readout and Digitizing System for ATLAS TileCal Demonstrator
2013
A potential upgrade for the front-end electronics and signal digitization and data acquisition system of the ATLAS hadron calorimeter for the high luminosity Large Hadron Collider (HL-LHC) is described. A Demonstrator is being built to readout a slice of the TileCal detector. The on-detector electronics includes up to 48 Analog Front-end Boards for PMT analog signal processing, 4 Main Boards for data digitization and slow controls, 4 Daughter Boards with high speed optical links to interface the on-detector and off-detector electronics. Two super readout driver boards are used for off-detector data acquisition and fulfilling digital trigger.\n The ATLAS Tile Calorimeter on-detector electron…