Showing papers on "Neutrino detector published in 1982"

Standard solar models and the uncertainties in predicted capture rates of solar neutrinos

Abstract: caused by a specified uncertainty in any of the parameters is evaluated with the aid of a series of standard solar models that were constructed for this purpose; the results are expressed in terms of the logarithmic partial derivative of each flux with respect to each parameter. The effects on the neutrino fluxes of changing individual parameters by large amounts can usually be estimated to satisfactory accuracy by making use of the tabulated partial derivatives. An overall "effective 3o. level of uncertainty" is defined using the requirement that the true value should lie within the estimated range unless someone has made a mistake. Effective 3o. levels of uncertainty, as well as best estimates, are determined for the following possible detectors of solar neutrinos: H, Li, Cl, 'Ga, Br, 'Br, Mo, Mo, ' In, and electronneutrino scattering. The most important sources of uncertainty in the predicted capture rates are identified and discussed for each detector separately. For the Cl detector, the predicted capture rate is 7.6+3.3 (effective 3o. errors) SNU. The measured production rate is (Cleveland, Davis, and Rowjley, 1981) 2. 1+0.3 SNU ( lo. error). For a 'Ga detector, the expected capture rate is 106(1+o08) SNU (also effective 3o. errors). The relatively small uncertainty quoted for the Ga detector is a direct result of the fact that 'Ga is primarily sensitive to neutrinos from the basic proton-proton reaction, the rate of which is determined largely by the observed solar luminosity. The Caltech and Munster measured values for the cross-section factor for the reaction He(a, y) Be are inconsistent with each other. The capture rates quoted above were obtained using the Caltech value for the cross-section factor. If the Munster value is used instead, then the predicted capture rate for the Cl experiment is 4.95+ 2. 1 SNU (effective 3o. errors) and, for the 'Ga experiment, 96.7 (1 ~&o8} SNU (effective 3o. errors). In order for the bestestimate value to agree with the observation of Davis (1978) of 2 SNU for the Cl experiment, the cross-section factor S34 (0) would have to be reduced by about 15o. to less than the Caltech value, i.e. to 7o. less than the Munster value. The characteristics of the standard solar model, constructed with the best available nuclear parameters, solar opacity, and equation of state, are presented in detail. The computational methods by which this and similar models were obtained are also described brieAy. The primordial helium abundance inferred with the aid of standard solar models is Y = 0.25+ 0.01. The complementary relation between observations of solar neutrinos and of the normal modes of oscillation of the sun is examined. It is shown that the splitting of the observed large-n, small-l, p-mode (five minute) oscillations of the sun primarily originates in the outer ten percent of the solar mass, while the neutrinos from B beta decay originate primarily in the inner five percent of the solar mass. The solar luminosity, and the flux of neutrinos from the proton-proton reaction, come mostly from an intermediate region.

Possibility of detecting relict massive neutrinos

Abstract: The coherent intensification of the interaction of relict massive neutrinos with grains of matter with a size on the order of the neutrino wavelength suggests that it might be possible to detect a galactic neutrino sea by virtue of the mechanical pressure which it exerts in the direction opposite that in which the solar system is moving in the galaxy.

Method and apparatus for the detection of neutrinos and uses of the neutrino detector

Abstract: Neutrinos are detected by allowing them to scatter on nuclei contained in a detector and by detecting the recoil of the nuclei. Because the probability of a neutrino being scattered is very low the probability is very high that a neutrino will only cause recoil of a single nucleus. On the other hand background radiation is likely to cause the recoil of a large number of electrons and/or nuclei so that neutrino scattering can be detected by distinguishing between the recoil of a single nucleus and the simultaneous recoil of a plurality of electrons/nuclei. In one form of the detector the nuclei are present as minute superconducting metal grains which are held in the superconducting state. At low temperatures the grains have a very low specific heat and the scattering of a neutrino will cause a single grain to heat up and change from the superconducting to the normal conducting state. This change will result in a perturbation of an applied magnetic field, as a result of the Meissner effect, and the perturbation of the magnetic field can be detected, for example as an e.m.f. induced in a detector loop. Several different superconducting arrangements are described. A semiconductor arrangement for detecting nuclear recoil is also described. The neutrino detector can be used, among other things, for monitoring reactor activity and for prospecting for subterranean deposits of radioactive elements, minerals found in association with these elements, and oil and gas.

The infancy and youth of neutrino physics : some recollections

Abstract: The talk is quite subjective in character, and is in no way complete. It is not a chapter of history of particle physics. It is a collection of a few short stories related to neutrino physics. Two of these, about Pauli and Fermi, touch on subjects already covered by a number of physicists, including the suthor, in connection with the recent neutrino's fiftieth birthday. A story about Majorana's work on Majorana's fermions, which is following, has been covered much less extensively, at least in English. There follow a few recollections, very personal indeed, related to the experimental and theoretical work of the author in proposing and developing the Cl-A method of neutrino detection, in establishing the notion of weak processes and in proposing a new type of weak interaction investigations - high energy neutrino experiments.

Medium-energy neutrinos in the universe

Abstract: The number density and energy spectrum of 3--30 MeV neutrinos and their influence on a solar neutrino detector are calculated on the basis of recent theoretical estimates for supernova neutrino emission, supernova rate data, and the heavy-element abundance of galactic matter. The evolution of galaxies is taken into account. At present the mass density of such neutrinos in the universe should be (2--10) x 10/sup -33/ g/cm/sup 3/, greater than the equivalent density of the cosmic background radiation. But unlike matter and the microwave radiation, which probably were created at the start of the cosmological expansion, medium-energy neutrinos would have developed subsequent to star formation at epochs z< or approx. =10 and would still be produced today. About 20 neutrino pulses should reach the observer each second from supernovae within the volume z<1; each pulse would last approx.10/sup 2/--10/sup 6/ sec if the neutrino rest mass is 0--30 eV, and the relative pulsation amplitude would be approx.10/sup -2/--10/sup -4/.

Cosmic-ray-neutrino tests for heavier weak bosons and cosmic antimatter

Abstract: We present a broad program for using high-energy neutrino astronomy with large neutrino detectors to directly test for the existence of heavier weak intermediate vector bosons (IVB's) and cosmic antimatter. Changes in the total cross section for ..nu..N..--> mu..X due to additional propagators are discussed and higher-mass resonances in the annihilation channel nu-bar/sub e/e/sup -/..-->..X are analyzed. The annihilation channel is instrumental in the search for antimatter, particularly if heavier IVB's exist.

The Operation of a Large Flash Chamber Neutrino Detector at Fermilab

Abstract: The operation of a large flash chamber neutrino detector at Fermilab is described. The detector consists of 608 flash chambers, and 37 proportional chambers with an active area of 12'×12'. Planes of sand and steel shot are interleaved with the flash chambers and proportional chambers to provide a fine grain sampling of recoil showers. The mass of the detector is 340 tons. The calibration of the instrument for electrons and hadrons in the energy range of 5 to 125 GeV is described.

Neutrino bursts from collapsing stars-results from the Homestake burst search

Abstract: The 300 ton water Cerenkov detector located at a depth of 4.2 km water equivalent in the Homestake gold mine has been searching for bursts of neutrinos since late 1978. The detector has sensitivity sufficiently high to observe 10 MeV neutrinos and antineutrinos from collapsing stars releasing 1053 erg of neutrino energy at a distance of 10 kpc. No neutrino bursts have been seen over a running time of 384 days.

The Supernova Neutrino Pulse Shape in the Scintillation Detector

Abstract: The temporal structure of the neutrino scintillation detector response to the supernova explosion signal is calculated, taking into account the duration and the spectrum of the supernova neutrino radiation and also the neutrino rest-mass.

Low-Energy Neutrinos in Astrophysics

Abstract: In this review we shall concentrate on the two main aspects of low-energy (∿MeV) neutrino astrophysics. The larger part summarizes the current status of solar neutrino research, whereas in the last section the prospects for the detection of collapsing star neutrinos are discussed.

Study of the sun's neutrino brightness curve with the help of a chlorine-argon neutrino detector

Abstract: It is shown that the rate of formation of /sup 37/Ar in the Brookhaven solar-neutrino detector oscillates with periods 20 +- 1, 25.5 +- 1.5 months, and approx.11 years and with a modulation depth > or approx. =0.3 with a confidence level not lower than 99.5%. These oscillations are interpreted as resulting from the modulation of the neutrino flux by gravitational oscillations at the center of the sun. Further experiments for studying the sun's neutrino brightness curve with the help of the chlorine-argon neutrino detector are discussed.

New Neutrino Detection Technology: Application of Massive Water Detectors to Accelerator Neutrino Physics

Abstract: In surveying the field of new detector technology, it appears that the advent of massive, inexpensive water Cerenkov detectors may have a significant impact on future neutrino physics These detectors offer the volumes necessary to perform experiments at very low fluxes, for example with long neutrino flight paths or with rare neutrino species (e g νe) As an illustration of the potential on the new techniques, we consider in detail an experiment dedicated to the study of the time evolution of a neutrino beam enriched with νe’s The highest fluxes of νe appear to be achieved with current beam lines at the Brookhaven AGS or the CERN PS An array of massive, inexpensive detectors allows a configuration optimized for good sensitivity to neutrino eigenmass differences from 06 eV to 20 eV and mixing angles down to 15° (comparable to the Cabibbo angle) The νe beam is formed using $$\mathop {\text{K}} olimits_{{\text{e3}}}^{\text{o}}$$ decays A simultaneously produced νμ beam from $$\mathop {\text{K}} olimits_{{\text{e3}}}^{\text{o}}$$ decay serves as the normalizer Pion generated νμ’s are suppressed to limit background The detector consists of a series of seven water Cerenkov modules (each with 175T fiducial mass), judiciously spaced along the ν line to provide flight paths from 40m to 1000m Simulation and reconstruction of neutrino events in a detector similar to the one considered show sufficient resolution in angle, energy, position and event timing relative to the beam