R.C. Ball

Hadron calorimetry in the L3 detector

Abstract The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e + e − collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granulatiry of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted.

The performance of a uranium gas sampling calorimeter

Abstract The performance of a uranium gas sampling hadron calorimeter is described. It has been observed that the hydrogen content of the gas mixture plays an important role in defining the behaviour of this type of calorimeter. The low-energy neutrons emerging from a hadron cascade are detected much more efficiently in a hydrogenous gas; thus leakage or containment of these neutrons becomes an important feature of the calorimeter setup.

Development of a plasma panel radiation detector

This article reports on the development and experimental results of commercial plasma display panels adapted for their potential use as micropattern gas radiation detectors. The plasma panel sensor (PPS) design and materials include glass substrates, metal electrodes and inert gas mixtures which provide a physically robust, hermetically sealed device. Plasma display panels used as detectors were tested with cosmic ray muons, beta rays and gamma rays, protons, and thermal neutrons. The results demonstrated rise times and time resolution of a few nanoseconds, as well as sub-millimeter spatial resolution compatible with the pixel pitch.

Test results from a uranium hadron calorimeter using wire chamber readout

Abstract A uranium gas sampling calorimeter has been tested with electrons and pions between 1 and 50 GeV. A comparative evaluation of the response and the resolution for proportional and streamer mode operation of the gas wire chamber detectors is given for two different gas mixtures.

The performance of an L3 hadron calorimeter prototype module with BGO

Abstract A prototype of a gas sampling uranium module of the L3 hadron calorimeter was built and subsequently tested with pion beams of energies between 4 and 20 GeV. The construction of the proportional chambers, the assembling of the module, the readout electronics, and the beam test are briefly described. The energy resolution of the calorimeter module alone was measured to be 30.5 ± 3% at 6 GeV, 21 ± 2% at 10 GeV and 18 ± 2% at 20 GeV. For the module together with a BGO crystal matrix in resolution was 29 ± 3% at 4 GeV, 21 ± 2% at 10 GeV, and 17 ± 2% at 20 GeV.

Plasma panel sensors for particle and beam detection

The plasma panel sensor (PPS) is an inherently digital, high gain, novel variant of micropattern gas detectors inspired by many operational and fabrication principles common to plasma display panels (PDPs). The PPS is comprised of a dense array of small, plasma discharge, gas cells within a hermetically-sealed glass panel, and is assembled from non-reactive, intrinsically radiation-hard materials such as glass substrates, metal electrodes and mostly inert gas mixtures. We are developing the technology to fabricate these devices with very low mass and small thickness, using gas gaps of at least a few hundred micrometers. Our tests with these devices demonstrate a spatial resolution of about 1 mm. We intend to make PPS devices with much smaller cells and the potential for much finer position resolutions. Our PPS tests also show response times of several nanoseconds. We report here our results in detecting betas, cosmic-ray muons, and our first proton beam tests.

Measurement of Γbb Γhad from hadronic decays of the Z

We report a measurement of R b = Γ bb Γ had from Z → qq events at LEP. View the Z → qq events are identified using a multidimensional analysis based on a neural network approach. We obtain 60% sample purity with an efficiency of 35%. Our measured value of R b is 0.222±0.003±0.007.

Performance of a fast, highly segmented electromagnetic calorimeter

Abstract We describe the energy, position, and angular resolutions of an electromagnetic calorimeter consisting of 56 layers of proportional wire and lead-filled tubes. The calorimeter was tested with two different electronic readout systems in a beam of electrons with energies ranging from 10 to 200 GeV.