[en] The processing of signals from ISIS 1 is described. Each of 80 self-triggering channels records the drift time and pulse height information for up to 30 or more tracks at any one time. This information is passed to CAMAC via a buffer memory. In addition the arrival times are projected on a display tube to show all the tracks passing through the 4m X 2m X 1.6m active volume of the chamber. (Auth.)

[en] Results are reported of a successful test of ISIS 1 in a particle beam. ISIS 1 is a full aperture (4 m x 2 m) prototype of the particle identifier ISIS (Identification of Secondaries by Ionisation Sampling), proposed for the European Hybrid Spectrometer (EHS) at the SPS at CERN. Using the 'relativistic rise' of the ionisation loss, electrons and pions at 500 MeV/c were identified with better than 99% confidence, the data containing typically 5-10 tracks per 'picture' drifted by up to 2 m. The ionisation resolution was 12-14% fwhm on 1 m of track and the two track resolution was 2 cm. These results, which agree with predictions, indicate that ISIS 2 with 5 m of useful track length will be able to distinguish uniquely kaons and protons from pions of known momentum in high multiplicity interactions up to 50 and 100 GeV/c respectively. (Auth.)

[en] A method to determine the z-coordinate of a track using a time-difference measurement has been developed for the ZEUS Central Tracking Detector. It has been demonstrated that a spatial resolution of 50 mm can be obtained under normal chamber operating conditions. This corresponds to a time-difference resolution of 330 ps. A method of minimizing nonlinearities in the time-to-distance response is described. This uses an inductor to form a matching network to achieve resistive termination of the chamber. Test beam measurements from a prototype chamber are presented, demonstrating the effects of the chamber surface field and beam incidence angle on the time-difference resolution. (orig.)

[en] The operation of the ISIS2 pictorial drift chamber in the European Hybrid Spectrometer at the CERN SPS is described. The data analysis and calibration procedure are outlined. After a brief presentation of the quality of the spatial data from the chamber, the dE/dx data are treated in some detail. It is shown that an ionisation resolution of 3.5% rms (or 8.3% fwhm) is routinely obtained on a large majority of tracks entering the 8 m² acceptance of the device; this is within 20% of the theoretical limit of the performance. Samples of tracks identified as electrons, pions or protons by kinematic fitting to conversions or strange particle decays are used to check the quality of the mass identification. Misidentification rates and confidence levels for mass separation as a function of momentum for each mass pair are given. Some data are given on the effects of space charge and a measurement of the relativistic rise is reported. (orig.)

[en] A method of vertex triggering which uses a time difference measurement to determine the z coordinate of a track is under development for the ZEUS Central Tracking Detector. This incorporates a pipelined readout system. We describe the system and report on its performance. (orig.)

[en] The ZEUS experiment has a three-level trigger system to select electron-proton interaction events from a large anticipated background of proton beam-gas. The first level decision is formed using pipelined hardware processors clocked at the 96 ns beam crossing frequency. A vital component of this decision is discrimination against upstream events using tracking detector information. The processors use three-dimensional space points measured in the central tracking detector to find pointing tracks over most of the θ range, and include forward tracking detector information to improve the resolution and angular coverage in the proton forward direction. The processor design status and performance simulation results are presented. (orig.)

[en] The complete 5.4 kton MINOS far detector has been taking data since the beginning of August 2003 at a depth of 2070 meters water-equivalent in the Soudan mine, Minnesota. This paper presents the first MINOS observations of ν_μ and ν_μ charged-current atmospheric neutrino interactions based on an exposure of 418 days. The ratio of upward- to downward-going events in the data is compared to the Monte Carlo expectation in the absence of neutrino oscillations, giving R_up/down^data/R_up/down^MC=0.62_-0.14^+0.19(stat.) ± 0.02(sys.). An extended maximum likelihood analysis of the observed L/E distributions excludes the null hypothesis of no neutrino oscillations at the 98% confidence level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic field ν_μ and ν_μ interactions are separated. The ratio of ν_μ to ν_μ events in the data is compared to the Monte Carlo expectation assuming neutrinos and antineutrinos oscillate in the same manner, giving R_νμ/νμ^data/R_νμ/νμ^MC=0.96_-0.27^+0.38(stat.)±0.15(sys.), where the errors are the statistical and systematic uncertainties. Although the statistics are limited, this is the first direct observation of atmospheric neutrino interactions separately for ν_μ and ν_μ.

[en] The readout system developed for the ZEUS central tracking detector (CTD) is described. The CTD is required to provide an accurate measurement of the sagitta and energy loss of charged particles as well as provide fast trigger information. This must be carried out in the HERA environment in which beams cross every 96 ns. The first two aims are achieved by digitizing chamber pulses using a pipelined 104 MHz FADC system. The trigger uses a fast determination of the difference in the arrival times of a pulse at each end of the CTD. It processes this data and gives information to the ZEUS global first level trigger. The modules are housed in custom-built racks and crates and read out using a DAQ system based on Transputer readout controllers. These also monitor data quality and produce data for the ZEUS second level Trigger. (orig.)

[en] During the period July 1987 through March 1988, a section of the Soudan 2 active shield known as the 'Tracker' recorded ∼250,000 muon tracks. The detector is located in the Tower-Soudan State Park in Soudan, Minnesota USA at a depth of 2090 meters-water equivalent. We have analysed the data collected and searched for time-dependent astronomical sources. Distributions in azimuthal and zenith angles as well as declination and right ascension are shown. 1 ref., 7 figs., 1 tab

[en] The design concept and development of the ZEUS central tracking detector is described. This is a cylindrical drift chamber designed for track reconstruction, electron identification and event triggering in a high-crossing-rate, high-magnetic-field environment. (orig.)