The CEBAF large acceptance spectrometer (CLAS) is used to study photo- and electro-induced nuclear and hadronic reactions by providing efficient detection of neutral and charged particles over a good fraction of the full solid angle. A collaboration of about 30 institutions has designed, assembled, and commissioned CLAS in Hall B at the Thomas Jefferson National Accelerator Facility. The CLAS detector is based on a novel six-coil toroidal magnet which provides a largely azimuthal field distribution. Trajectory reconstruction using drift chambers results in a momentum resolution of 0.5% at forward angles. Cherenkov counters, time-of-flight scintillators, and electromagnetic calorimeters provide good particle identification. Fast triggering and high data-acquisition rates allow operation at a luminosity of 10 34 nucleon cm −2 s −1 . These capabilities are being used in a broad experimental program to study the structure and interactions of mesons, nucleons, and nuclei using polarized and unpolarized electron and photon beams and targets. This paper is a comprehensive and general description of the design, construction and performance of CLAS.

/pdf/the-cebaf-large-acceptance-spectrometer-clas-2u9ne3shdl.pdf

The CEBAF large acceptance spectrometer (CLAS)

The KLOE calorimeter is a fine lead-scintillating fiber sampling calorimeter. We describe in the following the calibration procedures and the calorimeter performances obtained after 3 years of data taking. We get an energy resolution for electromagnetic showers of 5.4%/ E (GeV) and a time resolution of 56 ps/ E (GeV) . We also present a measurement of efficiency for low-energy photons.

/pdf/the-kloe-electromagnetic-calorimeter-3kx4kct8hj.pdf

The KLOE electromagnetic calorimeter

The backward region of the H1 detector has been upgraded in order to provide improved measurement of the scattered electron in deep inelastic scattering events. The centerpiece of the upgrade is a high-resolution lead/scintillating-fibre calorimeter. The main design goals of the calorimeter are: good coverage of the region close to the beam pipe, high angular resolution and energy resolution of better than 2% for 30 GeV electrons. The calorimeter should be capable of providing coarse hadronic energy measurement and precise time information to suppress out-of-time background events at the first trigger level. It must be compact due to space restrictions. These requirements were fulfilled by constructing two separate calorimeter sections. The inner electromagnetic section is made of 0.5 mm scintillating plastic fibres embedded in a lead matrix. Its lead-to-fibre ratio is 2.3:1 by volume. The outer hadronic section consists of 1.0 mm diameter fibres with a lead-to-fibre ratio of 3.4:1. The mechanical construction of the new calorimeter and its assembly in the H1 detector are described.

/pdf/the-h1-lead-scintillating-fibre-calorimeter-g0i9tth1ag.pdf

The H1 lead/scintillating-fibre calorimeter

Using the HERA proton beam striking an internal wire target, sufficient numbers of B mesons are produced to allow a search for CP violation in B decays

/pdf/an-experiment-to-study-cp-violation-in-the-b-system-using-an-2lkg9n5a7m.pdf

An experiment to study CP violation in the B system using an internal target at the HERA proton ring

A set of 24 lead/scintillating "ber electromagnetic calorimeters has been constructed for the new muon (g!2) experiment at the Brookhaven AGS. These calorimeters were designed to provide very good energy resolution for electrons up to 3 GeV while also yielding excellent timing information. Special requirements in the experiment related to the uniformity of response, the short-term gain and timing stability, and the neutron background led to several unusual design features. The calorimeters were tested and calibrated with electrons in the energy range 0.5}4.0 GeV and have been installed and used in the muon storage ring. The design criteria, construction, and performance of the system are described. ( 2000 Elsevier Science B.V. All rights reserved. PACS: 29.40.V; 13.35.B; 14.60.E

/pdf/electromagnetic-calorimeters-for-the-bnl-muon-g-2-experiment-2h3gq83jcz.pdf

Electromagnetic calorimeters for the BNL muon (g-2) experiment

Electromagnetic calorimeter modules based on a uniform array of plastic scintillating fibers embedded in a lead alloy have been built and tested. Techniques have been developed to assemble large volumes of this composite material and to machine it into the tapered trapezoidal modules appropriate for modern, hermetically-sealed calorimeters with pointing geometry. Using this technique, a 300-element array of such modules has been built and instrumented. Prototypes and subsets of the larger array have been tested in electron and photon beams ranging in energy from 0.035 to 5.0 GeV. Improvements in fiber characteristics, assembly procedures, and geometrical optimization have led to substantial performance gains over previous similar detectors. The average resolution of these detectors is determined to be σ/E ≈ 6.3%/√E (GeV). The techniques of fabrication and the detector tests are described.

A high-resolution lead /scintillating fiber electromagnetic calorimeter

The Jetset experiment (PS 202) at LEAR will search for gluonic hadrons and other exotics in the interaction of in‐flight antiprotons with protons at rest. The mass range to be covered extends from 1.96 to 2.43 GeV. Our experiment uses a molecular hydrogen cluster jet target which is inserted in the LEAR ring and is surrounded by a general‐purpose detetor of advanced design. In ‘‘Phase I’’ the detector has been constructed to provide selection at the trigger level of four kaon events, allowing a search for resonances in the OZI‐forbidden, gluon‐rich reaction pp→φφ→4K. The combination of LEAR with our detector is unique in that it allows scanning over a large momentum range with excellent momentum resolution, implying corresponding excellent mass resolution. The physics interest in this process is outlined briefly, and the design of the detector elments is described in some detail. A brief discussion of possible upgrade paths (‘‘Phase II’’) for the detecor is given at the end.

M. A. Graham

Papers

A high-resolution lead /scintillating fiber electromagnetic calorimeter

The jetset experiment at Lear