S. Mufson

The macro detector at the Gran Sasso Laboratory

Abstract The MACRO detector is presently under construction, its installation at Gran Sasso being planned to start in September 1987. It is a large area detector, the acceptance for isotropic particle fluxes being around 10 000 m 2 sr, designed to search for rare phenomena in the cosmic radiation. It makes use of three detection techniques: liquid scintillator counters, plastic streamer tubes, and track-etch. It will perform a search for GUT monopoles (or any supermassive charged penetrating particle), a survey of cosmic point sources of HE gammas and neutrinos, a systematic study of the penetrating cosmic ray muons, and will be sensitive to neutrino bursts from gravitational stellar collapses in the Galaxy.

Study of penetrating cosmic ray muons and search for large scale anisotropies at the Gran Sasso Laboratory

Abstract The MACRO detector, located in the underground Gran Sasso Laboratory, had its initial data run from February 27 to May 30, 1989, using the first supermodule (SΩ∼800 m 2 sr ) . Approximately 245 000 muon events were recorded. Here are reported the results of the analysis of penetrating muons which determine the measured vertical muon flux at depths greater than 3000 m.w.e. In addition the data have been used to search for large scale anisotropies.

Limits on the antiproton/proton ratio in the cosmic radiation from 100 MeV to 1580 MeV

A search for antiprotons (p-bars) in the cosmic radiation with energies below 1580 MeV at the top of the atmosphere was performed using the PBAR balloon-borne magnetic spectrometer. No antiprotons were observed in 124,000 proton events. For the energy interval 100-640 MeV, an upper limit is reported to the p-bar/p ratio of 2.8 x 10 to the -5th at the top of the atmosphere, after correcting for instrumental efficiencies and contributions from secondary particles. No antiproton was observed in the energy interval 640-1580 MeV, which yields an upper limit to the p-bar/p ratio of 6.1 x 10. By combining both data sets, the limits on the p-bar/p ratio can be improved to 2.0 x 10 to the -5th. The detector performance and instrumental efficiencies of the individual detector components are discussed. A detail Monte Carlo calculation was used to evaluate the instrumental efficiency for both antiprotons and protons as a function of momentum. 48 refs.

The cosmic-ray He-3/He-4 ratio from 100 to 1600 MeV/amu

The Superconducting Magnet Instrument for Light Isotopes (SMILI) flew for 19 hours on September 1, 1989, with a residual overburden of 5 g/sq cm. It measured the charge, rigidity, and velocity of 30,000 cosmic-ray helium nuclei, with velocity determined by time-of-flight and Cerenkov techniques. Using these data, the flux and isotopic composition of helium as a function of energy were determined. The observed isotopic composition is consistent with that expected from interstellar propagation models inferred from the secondaries of CNO, in contrast to earlier observations which indicated an overabundance of He-3. We discuss constraints that this result places on cosmic-ray transport and solar modulation models.

Measurement of the Isotopic Composition of Cosmic-Ray Helium, Lithium, Beryllium, and Boron up to 1700 MeV per Atomic Mass Unit

We present data from the second flight of the superconducting magnet instrument for light isotopes (SMILI), which took place on 1991 July 24. This instrument was optimized to determine the isotopic composition of He, Li, Be, and B in the Galactic cosmic rays, up to an energy of 2 GeV amu-1. The abundances of He, Li, and B are found to be consistent with standard models of cosmic-ray propagation. Our measurement of the abundances of the beryllium isotopes suggests an enhancement of the fraction of the isotope 10Be over that found at low energy. Of 26 beryllium events, nine are found to be 10Be. Monte Carlo calculations based on this observation imply the mean lifetime of cosmic rays to be less than 6 Myr at the 97.5% confidence level.

The atmospheric charged kaon/pion ratio using seasonal variation methods

Observed since the 1950’s, the seasonal effect on undergrou nd muons is a well studied phenomenon. The interaction height of incident cosmic rays changes as the temperature of the atmosphere changes, which affects the production height of mesons (mostly pions and kaons). The decay of these mesons produces muons that can be detected underground. The production of muons is dominated by pion decay, and previous work did not include the effect of kaons. In this work, the methods of Barrett and MACRO are extended to include the effect of kaons. These efforts give rise to a new method to measure the atmospheric K/� ratio at energies beyond the reach of current fixed target exp eriments. These methods were applied to data from the MINOS far detector. A method is developed for making these measurements at other underground detectors, including OPERA, Super-K, IceCube, Baksan and the MINOS near detector.

The Search for Neutrino-Antineutrino Mixing Resulting from Lorentz Invariance Violation using neutrino interactions in MINOS

Abstract We searched for a sidereal modulation in the rate of neutrinos produced by the NuMI beam and observed by the MINOS far detector. The detection of such harmonic signals could be a signature of neutrino–antineutrino mixing due to Lorentz and CPT violation as described by the Standard-Model Extension framework. We found no evidence for these sidereal signals and we placed limits on the coefficients in this theory describing the effect. This is the first report of limits on these neutrino–antineutrino mixing coefficients.

Liquid Argon Time Projection Chamber research and development in the United States

A workshop was held at Fermilab on March 20-21, 2013 to discuss the development of liquid argon time projection chambers (LArTPCs) in the United States. The workshop was organized under the auspices of the Coordinating Panel for Advanced Detectors, a body that was initiated by the American Physical Society Division of Particles and Fields. All presentations at the workshop were made in seven topical plenary sessions: i) Argon Purity, ii) Cryogenics, iii) TPC and High Voltage, iv) Electronics, Data Acquisition and Triggering, v) Scintillation Light Detection, vi) Calibration and Test Beams, and vii) Software. This document summarizes the current efforts in each of these areas. It also highlights areas in LArTPC research and development that are common between neutrino experiments and dark matter experiments.

A large liquid scintillator detector for a long baseline neutrino oscillation experiment

Abstract We present the concept and design of a liquid scintillator detector for a long-baseline neutrino oscillation experiment. Neutrinos interact in 2.5 cm thick steel plates alternating with 2.0 cm thick planes of liquid scintillator. The scintillator is contained in multicell PVC extrusions containing individual 2 cm×3 cm cells up to 8 m long. Readout of the scintillation light is via wavelength-shifting fibers which transport light to pixellated photodetectors at one end of the cells.

A comprehensive characterization of Hamamatsu 16- and 64-anode PMTs

We are reporting preliminary results of studies of R59000-00-M16 and M64 tubes, manufactured by Hamamatsu Photonics, to be employed by the MINOS neutrino experiment. Our tests focused on anode response uniformity, gain, cross-talk, and linearity for light illuminating PMTs through a 1.2 mm diameter fiber.