Showing papers on "Neutrino detector published in 1993"

Neutrinos in Physics and Astrophysics

Abstract: This work provides an overview of the subject of neutrino physics that will be of value to both the serious graduate student and the professional physicist. The authors focus on topics vital to the understanding of the intrinsic properties of neutrinos, which are presented in terms of recent developments in the field and their applications to astrophysics. In a format that integrates neutrino physics and astrophysics data and theory, the authors analyze the predictions generated by various theories and compare those predictions with experimental results. Emphasis is placed on the solar neutrino problem, one of the most exciting areas of physics today. The book also features extensive pedagogical and formal treatments of neutrino oscillations in both vacuum and matter.

γ rays and neutrinos from a powerful cosmic accelerator

Abstract: Possibly the powerful radio quasar 3C273 will reveal its nature as an efficient proton accelerator up to energies of order ${10}^{11}$ GeV in the near future. It is shown in this paper that the shock-accelerated protons expected to be present in the quasar's plasma jet induce an unsaturated synchrotron cascade with electromagnetic radiation emerging in the x-ray and \ensuremath{\gamma}-ray ranges. While (including the synchrotron emission from the accelerated primary electrons) the broadband nonthermal emission from 3C273 can be explained over the observed 18 orders of magnitude, a flattening of the spectrum at the highest observed energies (a few GeV) is predicted that could be falsified by the Energetic Gamma Ray Experiment Telescope on board the Compton Gamma Ray Observatory. Above \ensuremath{\approxeq}100 GeV the cascade spectrum dramatically steepens again due to the absorption of the \ensuremath{\gamma}-ray photons by the host galaxy's strong infrared photon field from extended dust clouds, in accordance with the nondetection of 3C273 by Cher\'enkov telescopes. However, neutrinos from the hadronic interactions initiating the cascade are not damped and reach terrestrial experiments without any modification of their injected flux. In contrast with the neutrino flux from pp interactions, which are energetically unimportant in jets, p\ensuremath{\gamma} interactions generate a flat neutrino flux. Therefore it is emphasized that one must not simply normalize the expected neutrino flux by the observed \ensuremath{\gamma}-ray flux. Hence it is shown that the expected neutrino flux in the energy range relevant for underwater or under-ice detectors is much lower than assumed by many authors. On the other hand, with an increasing number of cosmic \ensuremath{\gamma}-ray sources at known positions, their neutrino detection should be feasible when it is realized that the angular resolution is the crucial design property for neutrino detectors.

IMB-3: a large water Cherenkov detector for nucleon decay and neutrino interactions

Abstract: The IMB experiment, a large water Cherenkov detector which began data collection in September 1982, has undergone several upgrades to improve light collection, on-line processing power, data throughput and buffering, calibration, and operating efficiency. The current device, known as IMB-3, enjoys a factor of four light collection advantage over its precursor. Since May 1986, it has been used to search for such diverse phenomena as nucleon decay, dark matter, neutrino oscillation, and magnetic monopoles, and to study stellar collapse and cosmic rays. Due to its large size and long exposure time IMB presents unique challenges. The design and operation of the IMB-3 detector are described in detail.

Calibration and performance of the CHARM-II detector

Abstract: The neutrino detector CHARM-II at CERN, consisting of a large target calorimeter equipped with streamer tubes and a muon spectrometer, has been exposed to a test beam of electrons, pions and muons with momenta between 2 and 60 GeV/c in order to study the digital response of the streamer tubes, the analog response of the pickup strips and the momentum resolution of the

Very high-energy neutrinos from the Sun

Abstract: The authors argue that the Sun is a bright point source of very high-energy (VHE) neutrinos, which are produced by the interactions of cosmic rays with solar matter The estimated flux of nu mu and nu mu , from the Sun exceeds considerably the atmospheric neutrino background at an energy above approximately 1 TeV The flux of VHE solar neutrinos should be used as a 'standard candle' of neutrino astronomy of point sources for a future generation of neutrino telescopes

222Rn emanation into vacuum

Abstract: A low-background ZnS scintillator cell based on a design by Lucas has been developed for 222 Rn detection. Typical cells have 63% detection efficiency and 3 counts per day background. The cells have been used in measurements of 222 Rn emanation rate into vacuum from materials to be used under water in the Sudbury Neutrino Observatory (SNO) solar neutrino detector. The results are presented and the impact on the SNO detector design is discussed.

Dilute scintillators for large volume tracking detectors

Abstract: Dilute scintillation mixtures emit isotropic light for both fast and slow particles, but retain the Cherenkov light cone from fast particles. Large volume detectors using photomultipliers to reconstruct relativistic tracks will also be sensitive to slow particles if they are filled with these mixtures. Our data show that 0.03 g/l of b-PBD in mineral oil has a 2.4:1 ratio (in the first 12 ns) of isotropic light to Cherenkov light for positron tracks. The light attenuation length is greater than 15 m for wavelength above 400 nm, and the scintillation decay time is about 2 ns for the fast component. There is also a slow isotropic light component that is larger (relative to the fast component) for protons than for electrons. This effect allows particle identification by a technique similar to pulse shape discrimination. These features will be utilized in LSND, a neutrino detector at LAMPF.

Projected performance of a large superfluid helium solar neutrino detector

Abstract: Based upon experiments carried out using radioactive sources to investigate the particle detection properties of superfluid helium we project a configuration for and the response of a full scale detector for solar neutrinos employing the roton/quantum evaporation technique.

Neutrino production of same-sign dimuons at the Fermilab Tevatron

Abstract: The rate of neutrino- and antineutrino-induced prompt same-sign dimuon production in steel was measured using a sample of μ−μ− events and 25 μ+μ+ events withPμ>9 GeV/c, produced in 1.5 millionvμ and 0.3 million\(\overline {v_\mu }\) induced charged-current events with energies between 30 GeV and 600 GeV. The data were obtained with the Chicago-Columbia-Fermilab-Rochester (CCFR) neutrino detector in the Fermilab Tevatron Quadrupole Triplet Neutrino Beam during experiments E 744 and E 770. After background subtraction, the prompt rate of same-sign dimuon production is (0.53±0.24)×10−4 pervμ charged-current event and (0.52±0.33)×10−4 per\(\overline {v_\mu }\) charged-current event. The kinematic distributions of the same-sign dimuon events after background subtraction are consistent with those of the non-prompt background due to meson decays in the hadron shower of a charged-current event. Calculations ofc\(\bar c\) gluon bremsstrahlung, based on improved measurements of the charm mass parameter and nucleon structure functions by the CCFR collaboration, yield a prompt rate of (0.09±0.39)×10−4 pervμ charged-current event. In this case,c\(\bar c\) gluon bremsstrahlung is probably not an observable source of prompt same-sign dimuons.

The Status of the Solar Neutrino Problem

Abstract: Perhaps the most outstanding discrepancy between prediction and measurements in current particle physics comes from the solar neutrino problem, in which a large deficit of high-energy solar neutrinos is observed. Many Nonstandard Solar Models have been invoked to try to reduce the predicted flux, but all have run into problems in trying to reproduce other measured parameters (e.g., the luminosity) of the Sun. Other explanations involving new physics such as neutrino decay and neutrino oscillations, etc. have also been proffered. Again, most of these explanations have been ruled out by either laboratory or astrophysical measurements. It appears that perhaps the most likely particle physics solution is that of matter enhanced neutrino oscillation, the Mikheyev-Smirnov-Wolfenstein (MSW) oscillations. Two new radiochemical gallium experiments, which have a low enough threshold to be sensitive to the dominant flux of low-energy p-p neutrinos, now also report a deficit and also favor a particle physics solution. The next generation of solar experiments promise to finally resolve the source of the ``solar neutrino problem`` by the end of this decade.

Physics studies with ICARUS and a hybrid ionization and scintillation fiber detector

Abstract: We discuss the physics possibilities for the ICARUS detector currently being tested at CERN. The physics potential goes from a massive proton decay detector to the study of solar neutrinos. In addition, the detection of ν μ → ν τ andν c → ν τ will be possible with such a detector. One major topic involves the possibility of a complete determination of the MSW solar neutrino parameters with the ICARUS. The possibility of detecting WIMPS with a scintillating fiber liquid argon (Ar) detector or fiber xenon (Xe) detector doped with Ar is also described. Some comments on the measurement of the 42 Ar level from an experiment at the Gran Sasso Laboratory will be made.

Supernova neutrino bursts, the SNO detector, and neutrino oscillations

Abstract: We provide diagnostics that fruitfully can be employed to extract information concerning neutrino oscillations and the MSW effect from the supernova neutrino burst data that it is anticipated the Sudbury Neutrino Observatory will soon obtain.

A new solar neutrino detector

Abstract: This paper describes the main features of the proposed low energy solar neutrino detector Borexino, planned to be installed at the Gran Sasso Laboratory. This real time detector is based on a massive, calorimetric, liquid scintillation spectroscopy technique, whose high luminosity is the base for the attempt to achieve a low signal detection threshold. After a description of the main structural components of the detector, of its performances in term of spatial and energy resolution, and of the neutrino reactions occurring in the liquid scintillator, a description of the crucial background topic is given. Finally the main implications of the physics program of the experiment are briefly illustrated.

Accelerator Sources of High Energy Cosmic Neutrinos

Abstract: This paper reviews some topics of current interest concerning observations of atmospheric neutrinos and searches for high energy neutrinos of extraterrestrial origin.

Recent results from Kamiokande solar neutrino observations

Abstract: Preliminary results from the first one year of the Kamiokande-III solar neutrino observations are presented. The average flux is consistent with that observed in the Kamiokande-II experiment. No evidence is found for a time variation of the 8B solar neutrino flux over the recent five years, when the new result is combined with the Kamiokande-II results.

Neutral-current detection in the Sudbury Neutrino Observatory

Abstract: The Sudbury Neutrino Observatory (SNO) will have the capability of detecting all active species of neutrinos with energies greater than 2.2 MeV by the neutral-current disintegration of deuterium. The comparison of this rate with the rate of inverse beta decay of the deuteron will yield a nearly model-independent answer to the question of whether electron neutrinos from the sun oscillate into mu or tau neutrinos. The signal of a neutral-current interaction is the liberation of a free neutron in the heavy-water detector, and we discuss a technique employing [sup 3]He proportional counters for registering these neutrons, particularly from the standpoint of the ultra-low backgrounds needed.

Solar neutrinos with three-flavor mixings.

Abstract: The recent{sup 71}Ga solar neutrino observation is combined with the {sup 37}Cl and Kamiokande-II observations in an analysis for neutrino masses and mixings. The allowed parameter region is found for matter enhanced mixings among all three neutrino flavors. Distortions of the solar neutrino spectrum unique to three flavors are possible and may be observed in continuing and next generation experiments.

The Monte Carlo code for the Borexino detector at LNGS

Abstract: A Monte Carlo code has been developed to study the neutrino interactions and any source of radioactive background inside the liquid scintillator detector Borexino. In this report we discuss the methods of event generation, tracking, reconstruction and analysis. The main results are suitable also in planning detectors devoted to the study of low energy rare events where the background problem is dominant.