J. Moreels

Construction of a cylindrical MWPC for the central tracking detector of H1

Abstract A set of two cylindrical multiwire proportional chambers, 2.2 meter long and 1 meter in diameter, are being built as part of the central tracking detector of the H1 experiment, at HERA. The chamber bodies are of sandwich type; the cathodes are segmented in pads. The transmission line, which is part of the sandwich, has an impedance matched to the preamplifiers. The electronic readout has been tested on a flat prototype chamber; the time resolution is well below the 96 ns bunch crossing time at HERA.

A measurement of the holographic minimum-observable beam branching ratio in the FERMILAB 15-ft bubble chamber

Holography has been used successfully in combination with conventional optics for the first time in a large cryogenic bubble chamber, the 15-Foot Bubble Chamber at Fermilab, during a physics run. The innovative system combined the reference beam with the object beam, illuminating a conical volume of {approx} 1.4 m{sup 3}. Bubble tracks from neutrino interactions with a width of {approx} 120 {micro}m have been recorded with good contrast. The ratio of intensities of the object light to the reference light striking the film is called the Beam Branching Ratio. We obtained in our experiment an exceedingly small minimum-observable ratio of (0.54 {+-} 0.21) x 10{sup -7}. The technology has the potential for a wide range of applications.