W. Sippach

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.

Design and implementation of a high precision readout system for the ZEUS calorimeter

Abstract The design of the readout system for the high resolution ZEUS calorimeter is described. The design employs 10 MHz switched capacitor pipelines and digital signal processors, and provides linear operation over a 17-bit dynamic range. The implementation of the design is also discussed.

Design and Implementation of the New D0 Level-1 Calorimeter Trigger

Increasing luminosity at the Fermilab Tevatron collider has led the D0 collaboration to make improvements to its detector beyond those already in place for Run IIa, which began in March 2001. One of the cornerstones of this Run IIb upgrade is a completely redesigned level-1 calorimeter trigger system. The new system employs novel architecture and algorithms to retain high efficiency for interesting events while substantially increasing rejection of background. We describe the design and implementation of the new level-1 calorimeter trigger hardware and discuss its performance during Run IIb data taking. In addition to strengthening the physics capabilities of D0, this trigger system will provide valuable insight into the operation of analogous devices to be used at LHC experiments.

Response of a uranium-scintillator calorimeter to electrons, pions and protons in the momentum range 0.5–10 GeV/c

Abstract We have exposed a sandwich calorimeter, consisting of 3.3 mm thick uranium pnterleaved with 2.6 mm thick scintillator tiles, to positive and negative electrons and pions and to protons in the momentum range of 0.5 to 10 GeV/c. We find that e/h is about 1 above 3 GeV/c, but decreases significantly for lower momenta. This ratio is the same for positive and negative pions and also for pions and protons of the same kinetic energy.

Radiation qualification of the front-end electronics for the readout of the ATLAS liquid argon calorimeters

The ATLAS detector has been built to study the reactions produced by the Large Hadron Collider (LHC). ATLAS includes a system of liquid argon calorimeters for energy measurements. The electronics for amplifying, shaping, sampling, pipelining, and digitizing the calorimeter signals is implemented on a set of front-end electronic boards. The front-end boards are installed in crates mounted between the calorimeters, where they will be subjected to significant levels of radiation during LHC operation. As a result, all components used on the front-end boards had to be subjected to an extensive set of radiation qualification tests. This paper describes radiation-tolerant designs, radiation testing, and radiation qualification of the front-end readout system for the ATLAS liquid argon calorimeters.

Development of the front end electronics for the ZEUS high resolution calorimeter

The development and design of the pipelined data acquisition system for the high-resolution ZEUS calorimeter are described. Details of the front-end analog card and its performance are presented. A description of the custom pipeline and buffer multiplexer chips is given, along with test results for the pipeline chip. In addition, some results are presented for a CCD (charge-coupled device) test system built to evaluate the pipeline principles using the ZEUS calorimeter prototype at the CERN PS. >

Measurement of the time development of particle showers in a uranium scintillator calorimeter

Abstract We report on the time evolution of particle showers, as measured in modules of the uranium-scintillator barrel calorimeter of the ZEUS detector. The time development of hadronic showers differs significantly from that of electromagnetic showers, with about 40% of the response to hadronic showers arising from energy depositions which occur late in the shower development. The degree of compensation and the hadronic energy resolution were measured as a function of integration time, giving a value of e π = 1.02 ± 0.01 for a gate width of 100 ns. The possibilities for electron-hadron separation based on the time structure of the shower were studied, with pion rejection factors in excess of 100 being achieved for electron efficiencies greater than 60%. The custom electronics used to perform these measurements samples the calorimeter signal at close to 60 MHz, stores all samples for a period of over 4 μs using analog switched capacitor pipelines, and digitizes the samples for triggered events with 12-bit ADCs.

Design and performance of a 10 MHz cmos analog pipeline

Abstract The development of an analog pipeline which will be used for the readout of the ZEUS high-resolution calorimeter is described. The pipeline will be built in CMOS-technology and will use the switched capacitor technique. Performance tests of a test chip which incorporates the main features of the pipeline are presented. The following results on the main parameters have been achieved: dynamic range about 8000:1, chargeup time better than 4 ns, timing accuracy better than 1 ns. First results on radiation sensitivity show that the chip operates properly up to 5 krad. On the basis of these results an improved design of a prototype chip has been started.

High rate drift chambers

Fermilab experiment 690, a study of target dissociation reactions pp + pX using an 800 GeVlc proton beam and a liquid hydrogen target, collected data in late 1991. The incident beam and 600-800 GeV/c scattered protons were measured using a system of six 6” x 4” and two 15” x 8” pressurized drift chambers spaced over 260 meters. These chambers provided precise measurements at rates above 10 MHz (2 MHz per centimeter of sense wire). The measurement resolution of the smaller chambers was 90 urn, and the resolution of the larger chambers was 125 pm. Construction details and performance results, including radiation damage, are presented.

Liquid ionization calorimetry with time-sampled signals☆

We present the results of a study of amplitude and timing measurements made in a liquid krypton electromagnetic calorimeter, using multiply sampled signals of the shaped waveform. The measurements were designed to emulate the type of data that will be available from a calorimeter operating at future hadron-hadron colliders with short (∼ 20 ns) spacing between bunch crossings. Data have been collected with 18 ns sample spacing on waveforms from individual calorimeter sections with a shaping time of 40 ns and from 5 × 5 tower analog sums with a shaping time of 50 ns. The amplitude was measured using the analog sum signal, and the timing was measured using the signal from the individual sections. The data were processed using the method of optimal filtering, and a reduction in the noise of about a factor of two over that for a single sample is seen when using multiple samples for determining the amplitude. We find an energy resolution of 6.7%E, in agreement with the resolution measured for the same calorimeter using a single sample measured at the peak of the waveform. The timing resolution for a section of a calorimeter tower with deposited energy ∈ can be expressed as (c∈)2 + σcal2, with a value of c of 0.38 GeV ns for the front section (the first 6 radiation lengths) and 0.70 GeV ns for the back section, and a value of 0.15 ns for σcal.