J. Dawson

Construction and beam test of the ZEUS forward and rear calorimeter

Abstract The forward and rear calorimeters of the ZEUS experiment are made of 48 modules with maximum active dimensions of 4.6 m height, 0.2 m width, 7 λ depth and maximum weight of 12 t. It consists of 1 X 0 uranium plates interleaved with plastic scintillator tiles read out via wavelength shifters and photomultipliers. The mechanical construction, the achieved tolerances as well as the optical and electronics readout are described. Ten of these modules have been tested with electrons, hadrons and muons in the momentum range 15–100 GeV/ c . Results on resolution, uniformity and calibration are presented. Our main result is the achieved calibration accuracy of about 1% obtained by using the signal from the uranium radioactivity.

The small angle rear tracking detector of ZEUS

Abstract The design, construction, installation, and performance of the small angle rear tracking detector of the ZEUS experiment are described. The results on electron position measurement, electron energy correction, and background reduction at the first-level trigger are presented. The impact on the measurement of the proton structure function is discussed.

The SOUDAN 2 detector: The design and construction of the tracking calorimeter modules

SOUDAN 2 is a 960-ton tracking calorimeter which has been constructed to search for nucleon decay and other phenomena. The full detector consists of 224 calorimeter modules each weighing 4.3 tons. The design and construction of the modules are described. The modules consist of finely segmented iron instrumented with 1 m long drift tubes of 15 mm internal diameter. The tubes enable three spatial coordinates and dE/dx to be recorded for charged particles traversing the tubes.

Propagation of Electromagnetic Waves in a Partially Dielectric Filled Circular Waveguide

A circular waveguide partially filled with dielectric is considered as the deflecting structure for a relativistic particle separator. The cutoff wavelengths and normalized phase velocity versus frequency characteristics are presented. The expressions for power, losses, deflecting fields, and transverse deflecting forces are also given. Our investigation shows that the dominant (HEM11) mode of the structure can be used as a transverse deflecting mode for synchronous particles in a relativistic particle separator.

The ATLAS High Level Trigger Region of Interest Builder

This article describes the design, testing and production of the ATLAS Region of Interest Builder (RoIB). This device acts as an interface between the Level 1 trigger and the high level trigger (HLT) farm for the ATLAS LHC detector. It distributes all of the Level 1 data for a subset of events to a small number of (16 or less) individual commodity processors. These processors in turn provide this information to the HLT. This allows the HLT to use the Level 1 information to narrow data requests to areas of the detector where Level 1 has identified interesting objects.

Construction and performance of a large area liquid scintillator cosmic ray anticoincidence detector

Abstract We describe details of the construction and performance of a large area cylindrical cosmic ray anticoincidence detector suitable for a medium energy neutrino experiment. The device provides 4π coverage with approximately 400 m2 of liquid scintillator. Cosmic ray muons are rejected on-line with an inefficiency of ⋍ 10−4 which is improved to a level of ⋍ 3 × 10−6 or less with the application of off-line cuts. We also discuss the custom electronics used to operate and read out the device. Results from studies of the attenuation of neutral cosmic ray backgrounds by passive shielding are included.

System architecture and hardware design of the CDF XFT online track processor

A trigger track processor is being designed for CDF Run 2. This processor identifies high momentum (P/sub T/>1.5 GeV/c) charged tracks in the new central outer tracking chamber for the CDF II detector. The design of the track processor, called the eXtremely Fast Tracker (XFT), is highly parallel and handle an input rate of 183 Gbits/sec and output rate of 44 Gbits/sec. The XFT is pipelined and reports the results for a new event every 132 ns. The XFT uses three stages, hit classification, segment finding, and segment linking. The pattern recognition algorithms for the three stages are implemented in Programmable Logic Devices (PLDs) which allow for in-situ modification of the algorithm at any time. The PLDs reside on three different types of modules. Prototypes of each of these modules have been designed and built, and are working. An overview of the hardware design and the system architecture are presented.

The observation of underground muons from the direction of Cygnus X-3 during the January 1991 radio flare

Abstract Muons recorded in the Soudan 2 underground nucleon decay detector from January 1989 to February 1991 have been examined for any correlation with the radio flares of Cygnus X-3 observed during this period. On two nearby days during the radio flare of January 1991 a total of 32 muons within 2.0° of the Cygnus X-3 direction were observed when 11.4 were expected.

Radiation Damage Testing Of Transistors For SSC Front-end Electronics

Over the ten year expected lifetime of a typical SSC detector operating at the design luminosity of 10{sup 33} cm{sup {minus}2}s{sup {minus}1}, the front-end electronics at large pseudorapidities may receive total doses as high as 20 MRad(Si) of ionizing radiation and 10{sup 16} neutrons/cm{sup 2}. Discrete JFETs and monolithic MOS and bipolar transistors have been irradiated at 10 MRad(Si) and 10{sup 14} neutrons/cm{sup 2}, and the effect on transfer characteristics and noise performance have been measured. All transistors were still functional after irradiation but suffered increased noise and the MOS transistors showed significant threshold shifts and increased leakage currents. 4 refs., 2 figs.

Rad-Hard Electronics Development Program for SSC Liquid-Argon Calorimeters

The development program for radiation-hard low-noise low-power front-end electronics for SSC calorimetry is described. Radiation doses of up to 20 MRad and neutron fluences of 1014 neutrons/cm2 are expected over ten years of operation. These effects are simulated by exposing JFETs to neutrons and ionizing radiation and measuring the resulting bias, leakage current and noise variations. In the case of liquid-argon calorimeters, a large part of the front-end circuitry may be located directly within the low-temperature environment (90 K), placing additional constraints on the choice of components and on the design. This approach minimizes the noise and the response time. The radiation damage test facilities at Argonne will also be described. These include sources of neutrons, electrons, and gamma radiation.