40 research outputs found
The BNO-LNGS joint measurement of the solar neutrino capture rate in 71Ga
We describe a cooperative measurement of the capture rate of solar neutrinos
by the reaction 71Ga(\nu_e,e^-)71Ge. Extractions were made from a portion of
the gallium target in the Russian-American Gallium Experiment SAGE and the
extraction samples were transported to the Gran Sasso laboratory for synthesis
and counting at the Gallium Neutrino Observatory GNO. Six extractions of this
type were made and the resultant solar neutrino capture rate was 64
^{+24}_{-22} SNU, which agrees well with the overall result of the gallium
experiments. The major purpose of this experiment was to make it possible for
SAGE to continue their regular schedule of monthly solar neutrino extractions
without interruption while a separate experiment was underway to measure the
response of 71Ga to neutrinos from an 37Ar source. As side benefits, this
experiment proved the feasibility of long-distance sample transport in ultralow
background radiochemical experiments and familiarized each group with the
methods and techniques of the other.Comment: 7 pages, no figures; minor additions in version
Measurement of the Solar Neutrino Capture Rate by the Russian-American Gallium Solar Neutrino Experiment During One Half of the 22-Year Cycle of Solar Activity
We present the results of measurements of the solar neutrino capture rate in
gallium metal by the Russian-American Gallium Experiment SAGE during slightly
more than half of a 22-year cycle of solar activity. Combined analysis of the
data of 92 runs during the 12-year period January 1990 through December 2001
gives a capture rate of solar neutrinos with energy more than 233 keV of 70.8
+5.3/-5.2 (stat.) +3.7/-3.2 (syst.) SNU. This represents only slightly more
than half of the predicted standard solar model rate of 128 SNU. We give the
results of new runs beginning in April 1998 and the results of combined
analysis of all runs since 1990 during yearly, monthly, and bimonthly periods.
Using a simple analysis of the SAGE results combined with those from all other
solar neutrino experiments, we estimate the electron neutrino pp flux that
reaches the Earth to be (4.6 +/- 1.1) E10/(cm^2-s). Assuming that neutrinos
oscillate to active flavors the pp neutrino flux emitted in the solar fusion
reaction is approximately (7.7 +/- 1.8) E10/(cm^2-s), in agreement with the
standard solar model calculation of (5.95 +/- 0.06) E10/(cm^2-s).Comment: English translation of article submitted to Russian journal Zh. Eksp.
Teor. Fiz. (JETP); 12 pages, 5 figures. V2: Added winter-summer difference
and 2 reference
Measurement of the solar neutrino capture rate with gallium metal
The solar neutrino capture rate measured by the Russian-American Gallium
Experiment (SAGE) on metallic gallium during the period January 1990 through
December 1997 is 67.2 (+7.2-7.0) (+3.5-3.0) SNU, where the uncertainties are
statistical and systematic, respectively. This represents only about half of
the predicted Standard Solar Model rate of 129 SNU. All the experimental
procedures, including extraction of germanium from gallium, counting of 71Ge,
and data analysis are discussed in detail.Comment: 34 pages including 14 figures, Revtex, slightly shortene
The Baksan gallium solar neutrino experiment
A radiochemical 71Ga-71Ge experiment to determine the integral flux of neutrinos from the sun has been constructed at the Baksan Neutrino Observatory in the USSR. Measurements have begun with 30 tonnes of gallium. An additional 30 tonnes of gallium are being installed so as to perform the full experiment with a 60-tonne target. The motivation, experiment procedures, and present status of this experiment are described. © 1990
Results from the Soviet-American gallium experiment
A radiochemical 71Ga-71Ge experiment to determine the primary flux of neutrinos from the Sun began measurements of the solar neutrino flux at the Baksan Neutrino Observatory in 1990. The number of 71Ge atoms extracted from 30 tons of gallium in 1990 and 57 tons in 1991 was measured in twelve runs during the period of January 1990 to December 1991. For the 1990 data, we observed the capture rate to be 20 + 15 -20 (stat) ± 32 (syst) SNU, resulting in a limit of less than 79 SNU (90% CL). This is to be compared with 132 SNU predicted by the Standard Solar Model. The 1991 data, taken with 57 tons of gallium, shows a non zero 71Ge signal. A final result from the 1990 and 1991 data is still pending completion of studies of possible systematic effects. © 1993
Measurement of the solar neutrino capture rate by SAGE and implications for neutrino oscillations in vacuum
The Russian-American solar neutrino experiment has measured the capture rate of neutrinos on metallic gallium in a radiochemical experiment at the Baksan Neutrino Observatory. Eight years of measurement give the result 67.2 (+7.2,-7.0) (+3.5,-3.0) SNU, where the uncertainties are statistical and systematic, respectively. The restrictions these results impose on vacuum neutrino oscillation parameters are given