R.C. Allen

Limits on the neutrino magnetic moment from a measurement of neutrino-electron elastic scattering☆

Abstract Upper bounds on the magnetic moments of muon neutrinos and electron neutrinos are inferred from a measurement of neutrino-electron elastic scattering. The limits obained are: μ ν e −10 μ Bohr (90%CL) and μ ν ¬ −10 μ Bohr (90% CL).

The CYGNUS extensive air-shower experiment

Abstract The CYGNUS extensive air-shower experiment is described. The design criteria, construction and operation details, and performance characteristics are presented. A discussion of the data analysis techniques is given. Finally, several enhancements and improvements in the apparatus are described.

Effects of oxygen and nitrogen on drifting electrons in a liquid argon TPC

Abstract The attenuation length of electrons drifting in liquid argon is examined as a function of electric drift field from 0.5 to 3.0 kV cm −1 , and of impurity level for low concentrations of oxygen (∼ ppb) and nitrogen (∼ ppm). Deviations from the “standard” formula are noted, possible explanations are discussed, and a new, semiempirical formula is proposed.

A measurement of the neutrino flux from a stopped-pion source

Abstract Using an instrumented proton beam stop, consisting of copper, lead, and water, the distribution and number of stopped π+ per incident proton was measured for proton energies of 716, 766, and 797 MeV. The decay sequence of stopped pions and muons produce a well defined spectrum of ν e , ν μ and ν μ . The present experiment determines the neutrino production f stopped π+ decay by measuring the ratio of stopping pions per incident proton to an uncertainty of 8%.

A large scale purification system for a liquid argon time projection chamber

Abstract A purification system based on reduced copper and molecular sieve has been built for a 7 m3 liquid argon time projection chamber and it has been succesfully tested. After the initial purification an attenuation length of 0.7 m at 0.5 kV cm−1 was measured by drifting electrons over distances up to 28 cm. Further purification yielded attenuation lengths ≥ 3.7 m at 0.5 kV cm− which corresponds to an impurity level of ≤ 0.2 ppb oxygen equivalent.

A detector system for the study of intermediate energy neutrino interactions

Abstract A 15 t fine-grained neutrino detector and high efficiency anticoincidence system are in operation at the LAMPF beam stop, an intense source of neutrinos with a maximum energy of 53 MeV. The primary use of this equipment is in an experiment which is directed towards the observation and cross section measurement of the ν e e − elastic scattering reaction. The design, operation, and performance of the apparatus is reported.

Search for the exotic decay μ+→e+ν̄eνμ

Abstract We search for the exotic decay μ+→e+ ν eνμ as a test of lepton number conversation. An exposure of ≈1020 μ+ -decay neutrinos to a 15 ton detector leads to a new upper bound for the branching ratio, RϵΓ(μ + →e + ν e ν μ /Γ(μ + →all), R .

Use of a neutrino detector for muon identification by the CYGNUS air-shower array

The muon content of extensive air showers observed by the CYGNUS experiment are measured by a well-shielded apparatus, originally used for accelerator neutrino detection. Primary identification and counting of muons relies on a 44 m2 array of multiwire proportional counters that has operated continuously since the experiments inception to the present time. During the experiments first 20 months, the central detector, consisting of flash-tube chambers, was used for high-resolution reconstruction of muon trajectories for a limited subsample of air showers. The ability to distinguish individual muons in the tracking device enabled verification and calibration of the muon counting by the proportional-counter system. The tracking capability was also used to verify the systematic pointing accuracy of the extensive air-shower arrival direction, as determined by the CYGNUS array, to better than 0.5°.

Search for UHE emission from 4U0115+63

We report here the preliminary results of our observations of the sporadic X‐binary system 4U0115+63. The CYGNUS air shower array has been collecting data since April 1986. No significant excess is seen from the direction of this source, nor any correlation with its 24‐day orbital period. A 90% confidence‐level upper limit on the flux from 4U0115+63 is 2.8×10−13 cm−2 s−1 above 50 TeV. This flux limit is considerably lower than those reported by other UHE experiments. Search for periodicity at the neutron star frequency is in progress.

Recent data from the CYGNUS experiment

Data from the CYGNUS extensive air shower experiment at Los Alamos, NM has been analyzed to study the angular resolution of the array, and to search for point sources in the galaxy. Results on searches for steady emission from Cyg X‐3, Her X‐1 and the Crab nebula are presented.