C.B. Brooks

The Atmospheric Neutrino Flavor Ratio from a 3.9 Fiducial Kiloton-Year Exposure of Soudan 2

Abstract We report a measurement of the atmospheric neutrino flavor ratio, R, using a sample of quasi-elastic neutrino interactions occurring in an iron medium. The flavor ratio (tracks/showers) of atmospheric neutrinos in a 3.9 fiducial kiloton-year exposure of Soudan 2 is 0.64±0.11(stat.)±0.06(syst.) of that expected. Important aspects of our main analysis have been checked by carrying out two independent, alternative analyses; one is based upon automated scanning, the other uses a multivariate approach for background subtraction. Similar results are found by all three approaches.

The Design and construction of the ZEUS central tracking detector

Abstract The mechanical, electrical and electronic design and construction of the ZEUS central tracking detector are described, together with the chamber monitoring and environmental control. This cylindrical drift chamber is designed for track reconstruction, electron identification and fast event triggering in a high beam-crossing rate, high magnetic field application.

Measurement of the atmospheric neutrino flavour composition in Soudan 2

Abstract The atmospheric neutrino flavour ratio measured using a 1.52 kton-year exposure of Soudan 2 is found to be 0.72 ± 0.19−0.07+0.05 relative to the expected value from a Monte Carlo calculation. The possible background of interactions of neutrons and photons produced in muon interactions in the rock surrounding the detector has been investigated and is shown not to produce low values of the ratio.

Development of the ZEUS central tracking detector

Abstract 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.

Study of cosmic ray composition in the knee region using multiple muon events in the Soudan 2 detector

Deep underground muon events recorded by the Soudan 2 detector, located at a depth of 2100 m of water equivalent, have been used to infer the nuclear composition of cosmic rays in the ``knee`` region of the cosmic ray energy spectrum. The observed muon multiplicity distribution favors a composition model with a substantial proton content in the energy region 8{times}10{sup 5}{endash}1.3{times}10{sup 7} GeV/nucleus. {copyright} {ital 1997} {ital The American Physical Society}

The Oxford Free Electron Laser Project

It is proposed to use the Oxford 10 MV Van de Graaff accelerator as an electron beam source for a free electron laser (FEL) operating in the far infra red (FIR). The configuration and layout of the Van de Graaff make it very suitable for conversion, with a potentially high efficiency for electron beam recovery. Using a 2 m long wiggler of 34 mm period, the FEL would operate in the 60-300 /spl mu/m wavelength band, with extension down to 30 /spl mu/m on the 3rd harmonic. When constructed, the FEL will support a programme of FEL research and development, concentrating at first on investigations of behaviour in the moderately high-gain regime (/spl equiv/ 100% per pass) and mechanisms for lasing on higher harmonics. It will also be the basis for a national UK user facility in the FIR.

The SOUDAN 2 detector: The design and construction of the tracking calorimeter modules

SOUDAN 2 is a 960-ton tracking calorimeter which has been constructed to search for nucleon decay and other phenomena. The full detector consists of 224 calorimeter modules each weighing 4.3 tons. The design and construction of the modules are described. The modules consist of finely segmented iron instrumented with 1 m long drift tubes of 15 mm internal diameter. The tubes enable three spatial coordinates and dE/dx to be recorded for charged particles traversing the tubes.

ATLAS beam test results

Abstract Many different configurations of electronics and semiconductor strip detectors were studied in 1995 using the ATLAS tracking detector test area at the H8 beam-line of the CERN SPS. A significant fraction of these investigations are presented elsewhere in this volume and this paper will concentrate on the results with silicon strip detectors read out with electronics preserving the pulse height information. Data has been collected with the ADAM, APV5 and FElix read-out chips on a number of different detectors. The first results are presented for read out with LHC electronics of detectors to the ATLAS-A specification of 112.5 μm pitch, employing n-strips in n-type silicon, capacitive coupling and intermediate strips. It is demonstrated that with adequate signal/noise, a spatial resolution of ⋍13 μm is attainable with these detectors.

A life time test of neutron irradiated light emitting diodes

Abstract The results of an accelerated life time test of neutron irradiated ABB Hafo radiation hard LEDs are presented. After a 1 MeV neutron irradiation with up to 1.4 × 10 14 n/cm 2 at the Rutherford Appleton Lab (RAL) ISIS facility, the LEDs have been operated without seeing any degradation due to ageing for a time which is estimated to correspond to about 57 years of operation in the ATLAS SemiConductor Tracker (SCT) at the Large Hadron Collider (LHC). The irradiation decreased the light output of the LEDs substantially, but during the operation of the LEDs a fast annealing of most of the irradiation damage was observed.

The observation of underground muons from the direction of Cygnus X-3 during the January 1991 radio flare

Abstract Muons recorded in the Soudan 2 underground nucleon decay detector from January 1989 to February 1991 have been examined for any correlation with the radio flares of Cygnus X-3 observed during this period. On two nearby days during the radio flare of January 1991 a total of 32 muons within 2.0° of the Cygnus X-3 direction were observed when 11.4 were expected.