4,149 research outputs found
COMMENT ON THE KAMIOKANDE ATMOSPHERIC NEUTRINO DEFICIT
I describe an attempt to understand the significance of the atmospheric
neutrino deficit observed by the Kamiokande neutrino detector. In particular, I
am concerned with the statistical significance quoted for the zenith-angle
dependence of the deficit, which has been cited as evidence for neutrino flavor
oscillations free of systematic uncertainties.Comment: 2pp. LATEX format. No figures. Postscript available at
ftp://fnald.fnal.gov/usr$root39/saltzberg/nu.p
Ross Ice Shelf in situ radio-frequency ice attenuation
We have measured the in situ average electric field attenuation length for
radio-frequency signals broadcast vertically through the Ross Ice Shelf. We
chose a location, Moore Embayment, south of Minna Bluff, known for its high
reflectivity at the ice-sea interface. We confirmed specular reflection and
used the return pulses to measure the average attenuation length from 75-1250
MHz over the round-trip distance of 1155 m. We find the average electric field
attenuation length to vary from 500 m at 75 MHz to 300 m at 1250 MHz, with an
experimental uncertainty of 55 to 15 m. We discuss the implications for
neutrino telescopes that use the radio technique and include the Ross Ice Shelf
as part of their sensitive volume.Comment: 6 pages, 7 figures, Fig. 7 updated and minor text changes made since
the published versio
Evaluation of Giga-bit Ethernet Instrumentation for SalSA Electronics Readout (GEISER)
An instrumentation prototype for acquiring high-speed transient data from an
array of high bandwidth antennas is presented. Multi-kilometer cable runs
complicate acquisition of such large bandwidth radio signals from an extensive
antenna array. Solutions using analog fiber optic links are being explored,
though are very expensive. We propose an inexpensive solution that allows for
individual operation of each antenna element, operating at potentially high
local self-trigger rates. Digitized data packets are transmitted to the surface
via commercially available Giga-bit Ethernet hardware. Events are then
reconstructed on a computer farm by sorting the received packets using standard
networking gear, eliminating the need for custom, very high-speed trigger
hardware. Such a system is completely scalable and leverages the hugh capital
investment made by the telecommunications industry. Test results from a
demonstration prototype are presented.Comment: 8 pages, to be submitted to NIM
Measurements of the Suitability of Large Rock Salt Formations for Radio Detection of High Energy Neutrinos
We have investigated the possibility that large rock salt formations might be
suitable as target masses for detection of neutrinos of energies about 10 PeV
and above. In neutrino interactions at these energies, the secondary
electromagnetic cascade produces a coherent radio pulse well above ambient
thermal noise via the Askaryan effect. We describe measurements of
radio-frequency attenuation lengths and ambient thermal noise in two salt
formations. Measurements in the Waste Isolation Pilot Plant (WIPP), located in
an evaporite salt bed in Carlsbad, NM yielded short attenuation lengths, 3-7 m
over 150-300 MHz. However, measurements at United Salt's Hockley mine, located
in a salt dome near Houston, Texas yielded attenuation lengths in excess of 250
m at similar frequencies. We have also analyzed early ground-penetrating radar
data at Hockley mine and have found additional evidence for attenuation lengths
in excess of several hundred meters at 440 MHz. We conclude that salt domes,
which may individually contain several hundred cubic kilometer water-equivalent
mass, provide attractive sites for next-generation high-energy neutrino
detectors.Comment: 21 pages, 8 figures, to be submitted to Nuclear Instruments and
Method
Measurements of radio propagation in rock salt for the detection of high-energy neutrinos
We present measurements of the transmission of radio/microwave pulses through
salt in the Cote Blanche salt mine operated by the North American Salt Company
in St. Mary Parish, Louisiana. These results are from data taken in the
southwestern region of the 1500 ft. (457 m) deep level of the mine on our third
and most recent visit to the mine. We transmitted and received a fast,
high-power, broadband pulse from within three vertical boreholes that were
drilled to depths of 100 ft. (30 m) and 200 ft. below the 1500 ft. level using
three different pairs of dipole antennas whose bandwidths span 125 to 900 MHz.
By measuring the relative strength of the received pulses between boreholes
with separations of 50 m and 169 m, we deduce the attenuation of the signal
attributed to the salt medium. We fit the frequency dependence of the
attenuation to a power law and find the best fit field attenuation lengths to
be 93 \pm 7 m at 150 MHz, 63 \pm 3 m at 300 MHz, and 36 \pm 2 m at 800 MHz.
This is the most precise measurement of radio attenuation in a natural salt
formation to date. We assess the implications of this measurement for a future
neutrino detector in salt.Comment: 33 pages, 10 figures. Submitted to Nuclear Inst. and Methods in
Physics Research,
- …