G. Voulgaris

The Barrel Ring Imaging Cherenkov counter of DELPHI

Abstract A short explanation is given of the Barrel Ring Imaging CHerenkov (BRICH) detector and its performance. We discuss in brief some of the requirements to run this detector. Special attention is paid to the functioning of the Cherenkov photon detector — a photosensitive gas-filled drift chamber where the photoelectrons drift to a MWPC of special construction. We illustrate the BRICH performance with some preliminary results.

NESTOR: A Neutrino particle astrophysics underwater laboratory for the Mediterranean

Abstract An underwater neutrino astrophysics laboratory, to be located in the international waters off the Southwest of Greece, near the town of Pylos is now under construction. In the last two years a group of physicists from Greece and Russia have carried out two demonstration experiments in 4km deep water, counting muons and verifying the adequacy of the deep sea site. Plans are presented for a 100, 000 m 2 high energy neutrino detector composed of a hexagon of hexagonal towers, with 1176 optical detector units. A progress report is given and the physics potential of a siggle tower with 168 phototubes (currently under construction) is described.

The optical module for the NESTOR neutrino telescope

NESTOR is a deep-sea water Cherenkov neutrino detector now under construction for deployment in the Mediterranean off Greece. Its key component is an optical module employing a photomultiplier tube with a 15 in. hemispherical photocathode in a transparent glass pressure housing. Extensive tests have been made on the sensitivity, uniformity, time resolution, noise rates and mechanical properties of the module: several test deployments have been made at sea.

Study of resolved high-pT neutral pions at the CERN ISR

Abstract The inclusive production of π 0 at large values of p T in pp collisions at the ISR has been studied. In this experiment the two photons are resolved and separately measured for p T values of up to 6 GeV/ c , giving confidence that the desired signal has been separated from various backgrounds.

The Haleakala gamma ray observatory

A 10 m2 multi-mirror telescope for observing Cherenkov light signals from atmospheric cascades is now operating at Mount Haleakala, Maui, Hawaii. It differs from other atmospheric Cherenkov detectors in accepting pulses that originate from single photoelectrons, employing two sets of 18 optically independent phototubes in a logic system with nanosecond time resolution to reject ambient light from the night sky. With an angular aperture of 1.3 × 10−4 sr, cosmic ray showers are observed at a rate of ∼ 0.5 hz at the zenith, with nearly complete rejection of ambient light. This rate for hadronic showers implies an effective threshold near 100 GeV for electromagnetic showers. Two regions of the sky, one centered on the source and the other separated by from it by 3.6° are simultaneously monitored. Examples of observations of episodic and periodic (pulsar) sources are given.

NESTOR: A status report

NESTOR is an underwater neutrino astrophysics laboratory to be located in the international waters of the southwest of Greece. The first phase of this experiment is the construction and deployment of one hexagonal tower consisting of 168 optical modules, with effective are of 20000m2 for E ⩾ TeV neutrinos. Over the past few years detailed studies of the site have been carried out while many tests have been performed. The current status of the preparation of the experiment and the future plans will be presented.

The calibration system for the DELPHI Barrel RICH detector

Abstract We have designed, constructed and installed a system that makes an accurate 3D map of the electron drift velocity and measures the space-charge distorting effects in the TPCs of the DELPHI Barrel RICH detector. Details of the design considerations, construction and production are given.

The experiment 705 electromagnetic shower calorimeter

Abstract Experiment 705 at Fermi National Accelerator Laboratory has designed, built, and operated a large acceptance, highly segmented electromagnetic shower calorimeter using SF5 lead glass, SCG1-C scintillating glass, and two types of gas-based fine-grained hodoscopes. The calorimeter was used to reconstruct photons and electrons with energies ranging from a few GeV/ c 2 to over 100 GeV/ c 2 in 300 GeV/ c pion and proton interactions on a lithium target at instantaneous interaction rates approaching several MHz. Construction details of the calorimeter are given. The readout electronics, calibration, and algorithms used to reconstruct the positions and energies of showering particles are discussed. Energy resolution, position resolution, and reconstruction efficiency are assessed using both calibration electron beams and electrons and π 0 mesons reconstructed in 300 GeV/ c interactions.

Status of NESTOR, a deep sea neutrino telescope in the Mediterranean

In the last few years a great interest has been expressed for the construction of a Neutrino Astroparticle Physics Laboratory in the Mediterranean. The NESTOR collaboration made important progresses and plans soon to deploy in deep sea a detector with ∼ 104 m2 effective surface. This detector will be able not only to demonstrate the validity of the experimental approach but also to start data collection and then real Neutrino Astrophysics. The status of the preparation of the experiment and the future programs are described.

Results from the E-705 electromagnetic shower position detector

A fine-grain hodoscope to measure the position of showers in the outer (>52 cm) region of the E-705 electromagnetic calorimeter is described. The hodoscope is constructed with two layers of vertical conducting plastic tubes for the X position measurement of showers. Y position measurement of showers was accomplished by cathode-induced horizontal strips. A 50/50-ethane mixture bubbled through isopropyl alcohol at 0 degrees C was circulated through the tubes in parallel. The tubes were operated at +1.925 kV on the wire (below the region of saturated avalanche) in the limited proportionality mode. The hodoscope is described, and results are presented for the position resolution, shower width, and charge detected as a function of calibration electron energy. >