A fast track trigger processor for the opal detector at LEP

A fast hardware track trigger processor being built for the OPAL experiment is described. The processor will analyse data from the central drift chambers of OPAL to determine whether any tracks come from the interaction region, and thereby eliminate background events. The processor will find tracks over a large angular range, |cos θ| 0.95. The design of the processor is described, together with a brief account of its hardware implementation for OPAL. The results of feasibility studies are also presented.     

Performance of the ALEPH detector at LEP

The performance of the ALEPH detector at the LEP e⁺e⁻ collider is reviewed. The accuracy of the tracking detectors to measure the impact parameter and momentum of charged tracks is specified. Calorimeters are used to measure photons and neutral hadrons, and the accuracy obtained in energy and angle is given. An essential property of the detector is its ability to identify particles; the performance in identification of electrons, muons, neutrinos (from missing energy), charged hadrons, π⁰'s and V⁰'s is described.     

The forward muon detector of the DELPHI experiment at LEP

The layout and construction of the muon drift chambers equipping the end caps of the DELPHI detector are described. The performance of this forward muon detection system, determined from cosmic ray tests and data collected during the first year of LEP operation, is presented.     

Front end electronics and cosmic ray tests of muon drift tubes for the SDC detector

A system of front end wire chamber electronics for a large scale array of muon drift tubes is described. Simulations of the tube performance with readout electronics are discussed and compared with cosmic ray measurements.     

Development of the central trigger system for the BELLE detector at the KEK B-factory

In this paper, we describe the design and development of the central trigger system (GDL) for the BELLE detector at the KEK B-factory. The GDL consists of four types of single width 6U VME modules (ITD, FTD, PSNM and TMD) which are designed using the programmable logic techniques of Xilinx FPGA and CPLD. Individual and combined performance tests of these modules are done and it is confirmed that the GDL functions as expected.     

Design and construction of the CDF central tracking chamber

We describe the design and construction of a large drift chamber of a novel design well adapted for operation in high magnetic fields and in the high track density environment of hadron colliders.     

Readout electronics for the vertex chamber of the TOPAZ detector at TRISTAN, KEK

A vertex chamber has been designed and constructed for the TOPAZ detector at TRISTAN, KEK. The chamber is a jet-cell-type chamber aimed at a position resolution of 30–50 μm and a double-track separation of less than 1 mm. In this article the design and performance of the readout electronics for the TOPAZ vertex chamber are described. 10 ns signal shaping with a rise time of 5 ns has been achieved.     

Data acquisition system and results for the ALEPH very forward luminosity monitor at LEP

The data acquisition system of the very forward luminosity monitor for the ALEPH detector at LEP is described. The data analysis performed to obtain the luminosity measurement is also presented. This monitor provides the instantaneous luminosity with good statistical precision and is used for verifying the beam collision conditions as well as the off-momentum electron background. Instantaneous and integrated luminosity values derived from this detector have become very useful for assuring the proper operation of the ALEPH detector.     

Data acquisition system for the VENUS detector at TRISTAN

A data acquisition system for the VENUS detector at the TRISTAN electron-positron collider is presented. The whole system of the VENUS detector consists of nine different kinds of principal detectors, and the total number of electronics channels of the system reaches about 30 000. A FASTBUS system was introduced as the main data path and the TKO and the CAMAC standard have also been utilized for the frontend electronics. A FASTBUS interface to an on-line computer (VAX11/780), simplex segment interconnect and many data acquisition modules were developed. Most of the data are analyzed in a VAX cluster system in real time. Data logging is done in a main frame computer (FACOM M382) by using an automatic loading cartridge tape subsystem.     

Trigger system for the TOPAZ detector at TRISTAN,KEK

A trigger system for the TOPAZ detector at the TRISTAN e⁺e⁻ collider has been developed. The system consists of an energy trigger and a track trigger. The track trigger uses track information from the inner drift chamber, the time-of-flight counters and the time projection chamber. A three-dimensional track reconstruction is performed with high-speed logic arrays. The design and the performance are described.     

电子提花龙头检测器系统设计

国产电子提花龙头以其低廉的价格、优异的性能,赢得了广阔的市场。电子提花龙头检测器作为电子提花龙头质量检测手段,在生产电子提花龙头的过程中是必需的,能够提高电子提花龙头产品的质量、减少此产品的后续维护、降低电子提花龙头成本和提升产品的竞争力。设计了一种能够用于检测针数为1152/1344/2688电子提花龙头的检测器,并且应用于生产中,取得了良好的效果。     

Particle identification with the opal jet chamber in the region of the relativistic rise

An important goal of the OPAL jet chamber is particle identification at high momenta by exploiting the relativistic rise of the energy loss. Extensive tests have been performed with the full scale prototype of the OPAL jet chamber to measure the energy loss in an argon-methane-isobutane mixture as function of momentum and particle species. The measurements were done under various operating conditions in order to optimise the operating point, to investigate sources of systematic errors, to monitor the stability of the energy loss measurement and to develop calibration procedures. The particle separation capability in the region of the relativistic rise has been studied at gas pressures of 3 and 4 bar. The adopted operating point represents a reasonable compromise between the requirements for particle identification and tracking accuracy.     

一种新型反应室的分析与实验

对振动阴极上粉体的运动分析表明粉粒在阴极表面停留的时间与阴极表面倾斜角、气体反吹速度和粉粒大小等有关，其停留时间可达10min以上。用这种等离子反应室对硅粉刻蚀，可在硅粉流经反应室一次即可刻蚀200nm的表面厚度。这意味着纯化硅粉的任务能一次完成。实验结果表明新反应室比常规反应室具有很大的优点。     

Diamond shaped cathode pads for the longitudinal coordinate from a drift chamber

Results are presented for a system of diamond shaped cathode pads which give the coordinate of an avalanche along the length of the wire of a large area drift chamber to an accuracy of 1 mm. To first order the method is insensitive to small lateral displacements of the signal wire and to the pulse height. Two sets of such pads, above and below the wire, and offset relative to one another longitudinally by a quarter of the repeat distance, provide a check sum which (1) validates the data, (2) helps to calibrate the non-linearities and (3) determines the resolution.     

Design aspects of the thermal system of a thermovac chamber

Thermal system for a 4 m diameter × 4.5 m height thermovac chamber (TVC) designed for the Indian Space Research Organisation (ISRO) is described. Both the gaseous nitrogen (GN₂) and liquid nitrogen (LN₂) circulation systems are elaborated. Thermal analysis is shown in some detail. Design curves showing the liquid nitrogen consumption and the heater power requirements against various shroud temperatures are presented. Various components of the thermal system are briefly described.     

Tension measurement of 7.6 m drift tubes of the VENUS muon detector

A semiautomated tension measurement system was developed and constructed for 7.6 m long drift tubes of the VENUS detector at KEK. The system utilizes the wire vibration method and consists of a 400 G, 40 cm long dipole magnet and two CAMAC modules. The voltage and phase shift induced in an anode wire are measured to detect the resonance frequency of wire vibration when an alternating current is applied to the wire in a magnetic field. Eight wires in a module can be consecutively measured by a computer control. The reproducibility of data measured by the system was found to be excellent and the accuracy of the measurement was also found to be satisfactory. Tension data obtained for 800 wires of 70 μm in diameter have the mean value of 394.4 gw with the rms deviation of 7.2 gw for the intended wire tension of 400 gw.