632 research outputs found
Development of Atmospheric Monitoring System at Akeno Observatory for the Telescope Array Project
We have developed an atmospheric monitoring system for the Telescope Array
experiment at Akeno Observatory. It consists of a Nd:YAG laser with an
alt-azimuth shooting system and a small light receiver. This system is
installed inside an air conditioned weather-proof dome. All parts, including
the dome, laser, shooter, receiver, and optical devices are fully controlled by
a personal computer utilizing the Linux operating system.
It is now operated as a back-scattering LIDAR System. For the Telescope Array
experiment, to estimate energy reliably and to obtain the correct shower
development profile, the light transmittance in the atmosphere needs to be
calibrated with high accuracy.
Based on observational results using this monitoring system, we consider this
LIDAR to be a very powerful technique for Telescope Array experiments. The
details of this system and its atmospheric monitoring technique will be
discussed.Comment: 24 pages, 13 figures(plus 3 gif files), Published in NIM-A Vol.488,
August 200
Lidar observation of ozone over Tsukuba (36 deg N, 140 deg E)
An ozone lidar system was installed at the National Institute for Environmental Studies (NIES) in Tsukuba, Japan in March 1988 and has been measuring vertical profiles of ozone (15 - 45 km) since September 1988. The lidar system consists of a XeCl (308 nm) excimer laser, its deuterium Raman shifter (339 nm), a XeF excimer laser (351 nm), a 2 m telescope, a receiving system and a data processing system. The precision of the derived ozone concentration is about 10 percent of an altitude of 40 km for a 4 hr observation. Temperature profiles (30 - 80 km) are also obtained from the Rayleigh scattering signals at 351 nm. Approximate 50 ozone measurements are carried out in a year and variations of vertical profiles of ozone such as seasonal variations and shorter-term variations are observed. Systematic errors due to aerosols had been negligible until the arrival of the stratospheric aerosols injected by the eruption of Mt. Pinatubo. Effects of the volcanic aerosols on ozone measurements depend on the differences between wavelengths used as the on- and off-resonance
Rational solutions of the Sasano system of type
We completely classify the rational solutions of the Sasano system of type
The rational solutions are classified to four classes by the
B\"acklund transformation group.Comment: We believe that the result is correct, but is not interestin
Precision measurement of vector and tensor analyzing powers in elastic deuteron-proton scattering
High precision vector and tensor analyzing powers of elastic deuteron-proton
d+p scattering have been measured at intermediate energies to investigate
effects of three-nucleon forces (3NF). Angular distribution in the range of
70-120 degree in the center-of mass frame for incident-deuteron energies of 130
and 180 MeV were obtained using the RIKEN facility. The beam polarization was
unambiguously determined by measuring the 12C(d,alpha)10B(2+) reaction at 0
degree. Results of the measurements are compared with state-of-the-art
three-nucleon calculations. The present modeling of nucleon-nucleon forces and
its extension to the three-nucleon system is not sufficient to describe the
high precision data consistently and requires, therefore, further
investigation
Performance of the neutron polarimeter NPOL3 for high resolution measurements
We describe the neutron polarimeter NPOL3 for the measurement of polarization
transfer observables with a typical high resolution of 300 keV
at 200 MeV.
The NPOL3 system consists of three planes of neutron detectors.
The first two planes for neutron polarization analysis are made of 20 sets of
one-dimensional position-sensitive plastic scintillation counters with a size
of 100 cm 10 cm 5 cm, and they cover the area of 100
100 .
The last plane for detecting doubly scattered neutrons or recoiled protons is
made of the two-dimensional position-sensitive liquid scintillation counter
with a size of 100 cm 100 cm 10 cm.
The effective analyzing powers and double scattering
efficiencies were measured by using the three kinds
of polarized neutrons from the , , and reactions at = 198 MeV.
The performance of NPOL3 defined as
are similar to that of the
Indiana Neutron POLarimeter (INPOL) by taking into account for the counter
configuration difference between these two neutron polarimeters.Comment: 28 pages, 18 figures, submitted to Nucl. Instrum. Methods Phys. Res.
Analyzing power for the proton elastic scattering from neutron-rich 6He nucleus
Vector analyzing power for the proton-6He elastic scattering at 71
MeV/nucleon has been measured for the first time, with a newly developed
polarized proton solid target working at low magnetic field of 0.09 T. The
results are found to be incompatible with a t-matrix folding model prediction.
Comparisons of the data with g-matrix folding analyses clearly show that the
vector analyzing power is sensitive to the nuclear structure model used in the
reaction analysis. The alpha-core distribution in 6He is suggested to be a
possible key to understand the nuclear structure sensitivity.Comment: 5 pages, 3 figures, accepted for publication as a Rapid Communication
in Physical Review
Search for point sources of neutrinos with KGF underground muon detectors
The proton decay detectors operated underground in the Kolar Gold Fields in India during 1980-1993 have recorded a large number of muon events. Out of these, 243 large zenith angle events were selected as being due to muons arising
from neutrino interactions in the surrounding rock. This selection was based on the different zenith angular distributions of the atmospheric and neutrino-induced
muons. These selected events are analysed here to look for powerful point sources of neutrinos
Isovector effective NN interaction in 28Si(p,n)28P(6-) at 198 MeV
We report measurements of the cross section and a complete set of polarization observables for the View the MathML source reaction at a bombarding energy of 198 MeV. The data are compared with distorted wave impulse approximation calculations employing response functions normalized to inelastic electron scattering. The spin-longitudinal polarized cross section IDq is slightly over-predicted by the calculations, while the normal spin-transverse polarized cross section IDn is significantly under-predicted. The calculated in-plane spin-transverse IDp and spin-scalar ID0 polarized cross sections agree well with the experimental data. These results are consistent with those for View the MathML source scattering at the same energy, and thus it is concluded that isospin-mixing effects are not responsible for the discrepancy between theory and experiment in the View the MathML source case. Energy half-off-shell effects as medium effects on the effective nucleon?nucleon interaction are also investigated and found to be too small to be responsible for the discrepancy
The Anisotropy of Cosmic Ray Arrival Direction around 10^18eV
Anisotropy in the arrival directions of cosmic rays around 10^{18}eV is
studied using data from the Akeno 20 km^2 array and the Akeno Giant Air Shower
Array (AGASA), using a total of about 216,000 showers observed over 15 years
above 10^{17}eV. In the first harmonic analysis, we have found significant
anisotropy of 4 % around 10^{18}eV, corresponding to a chance
probability of after taking the number of independent trials
into account. With two dimensional analysis in right ascension and declination,
this anisotropy is interpreted as an excess of showers near the directions of
the Galactic Center and the Cygnus region. This is a clear evidence for the
existence of the galactic cosmic ray up to the energy of 10^{18}eV. Primary
particle which contribute this anisotropy may be proton or neutron.Comment: 4pages, three figures, to appear in Procedings of 26th ICRC(Salt Lake
City
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