High Energy Physics Detectors Research Articles

A preliminary study of GaAs solid-state detectors for high-energy physics

The first phase of a study of GaAs as a base material for solid-state detectors has been completed. The main motivation behind this study is the greater radiation resistance of integrated circuits made of GaAs (compared with Si). Many diodes, of different sizes and shapes but built with the same technique, have been tested electrically and as detectors, using α sources and minimum-ionizing particles. The tests show that these devices work with a full detection effeciency, although there is evidence for trapping of a fraction of the charge produced by the particle inside the semiconductor.

Thin films of barium fluoride scintillator deposited by chemical vapor deposition

We have used metal-organic chemical vapor deposition (MOCVD) technology to coat optical substrates with thin (∼1−10 μm thick) films of inorganic BaF 2 scintillator. Scanning electron microscope (SEM) photographs indicate that high-quality epitaxial crystalline film growth was achieved, with surface defects typically smaller than optical wavelengths. The scintillation light created by the deposition of ionizing radiation in the scintillating films was measured with a photomultiplier and shown to be similar to bulk melt-grown crystals. The results demonstrate the potential of these composite optical materials for planar and fiber scintillation radiation detectors in high energy and nuclear physics, synchrotron radiation research, and in radiation and X-ray imaging and monitoring.

Use of fiber-optics for real-time control and data acquisition

The practical use of commercially available fiber-optic components for high-speed control of and readout from a small prototype of an electronics data acquisition system for a high-energy physics detector has been demonstrated. This is the SVX microvertex detector system being readied for CDF (Collider Detector at Fermilab). The fiber-optic components include the AMD TAXI parallel/serial transmitter and receiver sets and Hewlett-Packard HFBR 1414 optical transmitters and HFBR 2416 receivers. The SVX chip is controlled by a 12-b field, which is updated via the optical fiber every clock cycle. Digital data are generated by the SVX every cycle and returned to the host system via a separate fiber. In this demonstration, the cycle time was set to approximately 200 ns; extension to 100 ns is planned. The prototype test system set up at the Lawrence Berkeley laboratory is described, and performance results are given. The expansion of this prototype system to the operation of a full-scale microvertex physics detector front-end system is also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Applications of a-Si:H radiation detectors

Detection of various kinds of radiation (charged particles, X-ray and γ ray) with hydrogenated amorphous silicon (a-Si:H) layers is discussed. Some applications of a-Si:H radiation detectors in high energy physics, medical imaging, materials and life sciences are described in this paper.

UFMulti: A new parallel processing software system for HEP

UFMulti is a multiprocessing software package designed for general purpose high energy physics applications, including physics and detector simulation, data reduction and DST physics analysis. The system is particularly well suited for installations where several workstation or computers are connected through a local area network (LAN). The initial configuration of the software is currently running on VAX/VMS machines with a planned extension to ULTRIX, using the new RISC CPUs from Digital, in the near future.

Growth of BGO single crystals using a directional solidification technique

Bismuth germanate (Bi 4Ge 3O 12, BGO) crystals are currently used as scintillation detectors in high energy physics, as well as in sanitary physics experiments, for their superior performance with respect to NaI(T1) detectors. At the present, most of the commercially available crystals are obtained by the Czochralski pulling technique, albeit Bridgman grown crystals seem to present excellent characteristics, such to having been chosen for the LEP3 experiment at CERN in Geneve. In order to prove that these superior properties derive from a minor amount of dislocations and other structural defects, we have grown a number of large (25 × 25 × 150 mm 3) single crystals using a vertical Bridgman furnace explicitally designed for this scope and by suitably changing selected growth parameters like the temperature gradient in the solid and the growth rate. The results show that crystals with a very low dislocation density could be grown by this technique and that their brittleness could be reduced by a careful control of the post-growth cycle.

A PC Based FASTBUS Development System

A general purpose FASTBUS development system and test station based on the IBM™, PC is described. Designed to facilitate the development, testing and monitoring of the latest generation of high energy physics detectors, this system provides the user with the flexibility, performance, and speed of FASTBUS in a compact transportable package. The commercially available key components are: 1) a FASTBUS mini-crate, (2) a programmable FASTBUS Master, (3) a DMA interface and (4) a PC-type personal computer. In addition, a gateway to VME exists.

The use of nuclear emulsion in hybrid detectors for high energy physics

The use of nuclear emulsion in hybrid detectors for high energy physics

Recent Progress in Flash ADC's

Substantial progress has been made in the last two years in cost-performance ratio of the flash analog to digital converters. 50 K channel systems are being designed for high energy physics detectors.

Calibration of High Energy Physics Detectors Using Neutrons Generated from Compact Accelerator D-D and D-T Reactions

Neutrons in the energy range 0-14 MeV are easily obtainable from very compact pulsed accelerotors. The fluxes are sufficient to be useful for the calibration of large experiments in high energy physics. We outline a number of methods for the calibration of hadron and e-m calorimeters, and large chamber and counter arrays. We discuss the advantages and problems of such generators over standard radiochemical sources.

New approaches to particle detectors in high-energy physics

Some recent progress in particle detectors used in high-energy physics is relevant to the problems encountered with high-luminosity, high-duty-factor electron accelerators. Silicon strip detectors with a 5 μm accuracy are becoming a well-established technique. Thin multiwire chambers with rate capabilities of 10 7/cm 2 · s are operational. Drift chambers of special structures can be operated with accuracies below 100 μm and at very high rates. Bismuth germanate scintillators represent a major breakthrough in scintillator calorimetry of high resolution. Barium fluoride crystals coupled to photoionization wire chambers are a completely new approach to scintillator hodoscopes, combining localization, energy resolution, and pattern signatures for efficient particle identification.

Silicon detectors

The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters.

Present trends and realisations in readout electronics for semiconductor detectors in high energy physics

Design criteria of signal processors for semiconductor detectors in high energy physics experiments are reviewed. Choice of input active devices of preamplifiers, detector-device capacitive matching, preamplifier configurations, variant and invariant signal processors are discussed. Several examples of processors for microstrip silicon detectors and for silicon detector telescopes, are reviewed with particular emphasis on noise performance and high rate capabilities.

Applications of silicon detectors in high energy physics and astrophysics

Silicon detectors are being increasingly used in high energy physics and in astronomy. In the former case they are used for precisely locating the trajectories of particles which traverse the detectors, while in the latter case they are used for very low level light imaging. In both applications, the use of silicon is preferred because of the low energy needed to liberate an electron-hole pair in the medium and because of the highly developed planar technology which allows sophisticated devices with excellent spatial precision to be fabricated. The specific devices discussed are microstrip detectors and 2-dimensional imaging CCDs, including a summary of radiation damage since this is of importance in both the astronomical and particle physics applications.

New Developments in Flash ADC's

A new generation of Flash Analog to Digital Converters (FADC) is being designed by European, Japanese and U.S. companies. The driving force behind this new development is digital video-expected to be a very large market. The video FADC devices are mostly 8 bits with speeds in excess of 20 MHz. 10 bit devices are required for digital processing/restructuring of video images. We are interested in using these devices for high energy physics detectors.

First measurement of efficiency and precision of CCD detectors for high energy physics

It has been known for some time that a 2-dimensional charge-coupled device (CCD) might be used for detecting high energy particles with high precision and excellent 2-track resolution. Such detectors could be used to distinguish between prompt tracks and decay products in events producing short-lived particles (heavy leptons, charm, beauty etc.). We now present results in which (for the first time) a telescope of CCD detectors has been operated in a beam of high energy particles. The main results are that even these early detectors have excellent performance characteristics, namely efficiency for track detection of 98±2% per plane, spatial resolution of 4.3 μm and 6.1 μm in two orthogonal directions and 2-track resolution of 40 μm in space.

Optoelectronic link for analog signals from solid state detectors in high energy physics

An optoelectric link has been made to transmit analog signals over a long distance between the beam area and the remote-end data acquisition instrumentation in high energy experiments. The optoelectronic link is intended for silicon target applications and it is designed to work on the signals at the output of a low noise amplifier system. Its advantages over a conventional galvanic connection as well as its limitations are discussed.

Erratum to: Silicon detectors in high-energy physics: Physics and applications

Erratum to: Silicon detectors in high-energy physics: Physics and applications

Silicon detectors in high-energy physics: Physics and applications

The use of silicon detectors in high-energy physics dates back more than 13 years, especially for the study of coherent interaction on the silicon nucleus. Eecent advances in silicon detector technology, which coincided with the discovery of short-lived charmed particles, have enabled the design of experiments with complex detector configurations where thin (< 300 μm) detectors with small 100 μm) interspacing are employed. These detector systems are used mainly as active targets and multiplicity identifiers (for reaction detecting) in beams from high-energy accelerators where counting rates are very high (millions of pulses per second).

Triggering the LBL Time Projection Chamber

We have built a fast digital trigger for the LBL Time Projection Chamber (TPC) installed in the PEP-4 detector at SLAC. The TPC is an innovative High Energy Physics detector which will provide particle identification from dE/dx information within the tracking volume. The TPC trigger uses discriminator signals from 2,220 dE/dx wire channels to require a track of ionization in the TPC which originates from the colliding beam intersection region. The trigger processing is performed as the ionization drifts onto the proportional wires and is completed 17 μs after beam crossing. In this report, we describe the basic operation of the TPC detector and its trigger; a pretrigger which uses prompt TPC information from the endcap region; and the electronic implementation. The trigger can be tested with realistic simulated patterns of ionization deposits in the TPC which are stored in local memories. We show test results from electronic simulations and first results of a test with cosmic rays.