Tunka-133: Results of 3 year operation Prosin, V.V.; Berezhnev, S.F.; Budnev, N.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2014, Letnik:
756
Journal Article
Recenzirano
Odprti dostop
The EAS Cherenkov light array Tunka-133, with ~3km2 geometric area, is taking data since 2009. The array permits a detailed study of cosmic ray energy spectrum and mass composition in the PeV energy ...range. After a short description of the methods of EAS parameter reconstruction, we present the all-particle energy spectrum and results of studying CR composition, based on 3 seasons of array operation. In the last part of the paper, we discuss possible interpretations of the obtained results.
A new high light yield liquid scintillator based on linear alkylbenzene (LAB) as an organic solvent and a novel nanostructured organosilicon liminophore as a scintillation fluor has been developed ...for the next generation large-scale experiments in astroparticle physics. It is shown that the developed liquid scintillator has light yield almost two times higher than traditional LAB-based liquid scintillator with PPO fluor, when peak light yield values are compared, since the former peaks at 490 nm, while the latter peaks at 360 nm. At the same time light emission kinetics is characterized by about 10 ns decay time constant for its fastest component which contributes more than 80% to the total light yield of the scintillator.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The Baksan Experiment on Sterile Transitions (BEST) was designed to investigate the deficit of electron neutrinos νe observed in previous gallium-based radiochemical measurements with high-intensity ...neutrino sources, commonly referred to as the "gallium anomaly," which could be interpreted as evidence for oscillations between νe and sterile neutrino (νs) states. A 3.414-MCi 51Cr νe source was placed at the center of two nested Ga volumes and measurements were made of the production of 71Ge through the charged current reaction, 71Ga(νe,e-)71Ge, at two average distances. The measured production rates for the inner and the outer targets, respectively, are 54.9$_{-2.4}^{+2.5}$(stat)±1.4(syst) and 55.6$_{-2.6}^{+2.7}$(stat)±1.4(syst) atoms of 71Ge/d. The ratio (R) of the measured rate of 71Ge production at each distance to the expected rate from the known cross section and experimental efficiencies are Rin=0.79±0.05 and Rout=0.77±0.05. The ratio of the outer to the inner result is 0.97±0.07, which is consistent with unity within uncertainty. The rates at each distance were found to be similar, but 20%-24% lower than expected, thus reaffirming the anomaly. Therefore these results are consistent with νe→νs oscillations with a relatively large Δm2 (> 0.5 eV2) and mixing sin22θ (≈0.4).
The Tunka-133 EAS Cherenkov light array: Status of 2011 Berezhnev, S.F.; Besson, D.; Budnev, N.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2012, Letnik:
692
Journal Article
Recenzirano
Odprti dostop
A new EAS Cherenkov light array, Tunka-133, with ∼1km2 geometrical area has been installed at the Tunka Valley (50km from Lake Baikal) in 2009. The array permits a detailed study of cosmic ray energy ...spectrum and mass composition in the energy range 1016–1018eV with a uniform method. We describe the array construction, DAQ and methods of the array calibration. The method of energy reconstruction and absolute calibration of measurements are discussed. The analysis of spatial and time structure of EAS Cherenkov light allows to estimate the depth of the EAS maximum Xmax.
The results on the all particles energy spectrum and the mean depth of the EAS maximum Xmax vs. primary energy derived from the data of two winter seasons (2009–2011) are presented. Preliminary results of joint operation of the Cherenkov array with antennas for the detection of EAS radio signals are shown. Plans for future upgrades – deployment of remote clusters, radioantennas and a scintillator detector network and a prototype of the HiSCORE gamma-telescope – are discussed.
We present the status of research and development of a new highly efficient liquid scintillator based on linear alkylbenzene and organosilicon scintillation fluor, so called NOL (Nanostructured ...Organosilicon Luminophore). The measurements of the emission kinetics under irradiation by gamma-quanta and alpha-particles were performed. The results of long term stability measurements are decribed.
Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest-energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection ...requires instruments with large collecting areas. In this work, we report the detection of an extremely energetic particle recorded by the surface detector array of the Telescope Array experiment. We calculate the particle’s energy as
244
±
29
stat
.
−
76
+
51
syst
.
exa–electron volts
(~40 joules). Its arrival direction points back to a void in the large-scale structure of the Universe. Possible explanations include a large deflection by the foreground magnetic field, an unidentified source in the local extragalactic neighborhood, or an incomplete knowledge of particle physics.
Editor’s summary
Cosmic rays are charged particles from space. At low energies, they mostly originate from the Sun, whereas at high energies, they are expected to be emitted by nearby active galaxies. The Telescope Array Collaboration now reports the detection of a cosmic ray event with an energy of about 240 exa–electron volts, more than a million times higher than that achieved by artificial particle accelerators. Such high-energy particles should experience only small deflections by foreground magnetic fields, but tracing back the arrival direction shows no obvious source galaxy. The authors suggest that the foreground magnetic fields might be stronger than expected, or there could be unknown particle physics at high energies. —Keith T. Smith
Detection of a highly energetic cosmic ray is traced back to its arrival direction, but no source galaxy is evident.
This paper discusses the charge-exchange strength functions
of the isotopes
Te. The experimental data of the
strength functions obtained from (
He,
) reactions, as well as the
strength functions ...calculated in the microscopic theory of finite Fermi systems, are analyzed. The resonance structure of the strength function
is examined, and the Gamow–Teller and pygmy resonances are identified. The resonance structure of the strength function
is vital for the calculation and analysis of the process of neutrino capture by atomic nuclei.
The EAS Cherenkov light array Tunka-133, with ~ 3 km2 geometric area, is taking data since 2009.The array permits a detailed study of energy spectrum and mass composition of cosmic rays in the ...energy range from 6 · 1015 to 1018 eV. We describe the methods of time and amplitude calibration of the array and the methods of EAS parameters reconstruction. We present the all-particle energy spectrum, based on 7 seasons of operation.
Low background experiments need a suppression of cosmogenically induced events. The
Gerda
experiment located at
Lngs
is searching for the
0
ν
β
β
decay of
76
Ge. It is equipped with an active muon ...veto the main part of which is a water Cherenkov veto with 66 PMTs in the water tank surrounding the
Gerda
cryostat. With this system 806 live days have been recorded, 491 days were combined muon–germanium data. A muon detection efficiency of
ε
μ
d
=
(
99.935
±
0.015
)
% was found in a Monte Carlo simulation for the muons depositing energy in the germanium detectors. By examining coincident muon–germanium events a rejection efficiency of
ε
μ
r
=
(
99
.
2
-
0.4
+
0.3
)
% was found. Without veto condition the muons by themselves would cause a background index of
BI
μ
=
(
3.16
±
0.85
)
×
10
-
3
cts
/
(
keV
·
kg
·
year
)
at
Q
β
β
.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The scintillation light output of a pure and a Thallium doped Sodium Iodide (NaI) crystal under irradiation with 5.486 MeV
α
particles has been measured over a temperature range from 1.7 K to 300 K. ...Estimates of the decay time constant at three selected temperatures are given. For pure NaI an increase in light yield towards low temperatures could be confirmed and measured at higher precision. For NaI(Tl) below 60 K an increase in light output has been found.
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