258 research outputs found
Characteristics of liquid cluster ion beam for surface treatment
A liquid cluster ion source, which is an ion source for the cluster beams produced with liquid materials, has been developed for the surface treatment of solid materials. The electrodes were designed for increasing the cluster beam intensity by a computer simulation of beam trajectories. The peaks of the cluster size distributions of the water and ethanol cluster ion beams of 3 atm vapor pressure were approximately at 2.4×103 and 1.6×103 molecules, respectively. The cluster size distributions of ethanol clusters were not sensitive to the variations of the acceleration voltages (Ve) and currents (Ie) of the electrons for ionization when the Ve and Ie were larger than approximately 200 V and 200 mA, respectively
Design and performance of the muon monitor for the T2K neutrino oscillation experiment
This article describes the design and performance of the muon monitor for the
T2K (Tokaito-Kamioka) long baseline neutrino oscillation experiment. The muon
monitor consists of two types of detector arrays: ionization chambers and
silicon PIN photodiodes. It measures the intensity and profile of muons
produced, along with neutrinos, in the decay of pions. The measurement is
sensitive to the intensity and direction of the neutrino beam. The linearity
and stability of the detectors were measured in beam tests to be within 2.4%
and 1.5%, respectively. Based on the test results, the precision of the beam
direction measured by the muon monitor is expected to be 0.25 mrad.Comment: 22 page
Superconducting Fluctuations and the Pseudogap in the Slightly-overdoped High-Tc Superconductor TlSr2CaCu2O6.8: High Magnetic Field NMR Studies
From measurements of the ^{63}Cu Knight shift (K) and the nuclear
spin-lattice relaxation rate (1/T_{1}) under magnetic fields from zero up to 28
T in the slightly overdoped superconductor TlSr_{2}CaCu_{2}O_{6.8} (T_{c}=68
K), we find that the pseudogap behavior, {\em i.e.}, the reductions of 1/T_{1}T
and K above T_{c} from the values expected from the normal state at high T, is
strongly field dependent and follows a scaling relation. We show that this
scaling is consistent with the effects of the Cooper pair density fluctuations.
The present finding contrasts sharply with the pseudogap property reported
previously in the underdoped regime where no field effect was seen up to 23.2
T. The implications are discussed.Comment: 10 pages, 4 GIF figures, to be published in Phys. Rev. Let
Extension and its characteristics of ECRH plasma in the LHD
One of the main objectives of the LHD is to extend the plasma confinement
database for helical systems and to demonstrate such extended plasma
confinement properties to be sustained in steady state. Among the various
plasma parameter regimes, the study of confinement properties in the
collisionless regime is of particular importance. Electron cyclotron resonance
heating (ECRH) has been extensively used for these confinement studies of the
LHD plasma from the initial operation. The system optimizations including the
modification of the transmission and antenna system are performed with the
special emphasis on the local heating properties. As the result, central
electron temperature of more than 10 keV with the electron density of 0.6 x
10 m is achieved near the magnetic axis. The electron temperature
profile is characterized by a steep gradient similar to those of an internal
transport barrier observed in tokamaks and stellarators. 168 GHz ECRH system
demonstrated efficient heating at over the density more than 1.0 x 10
m. CW ECRH system is successfully operated to sustain 756 s discharge.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Common Variants in a Novel Gene, FONG on Chromosome 2q33.1 Confer Risk of Osteoporosis in Japanese
Osteoporosis is a common disease characterized by low bone mass, decreased bone quality and increased predisposition to fracture. Genetic factors have been implicated in its etiology; however, the specific genes related to susceptibility to osteoporosis are not entirely known. To detect susceptibility genes for osteoporosis, we conducted a genome-wide association study in Japanese using ∼270,000 SNPs in 1,747 subjects (190 cases and 1,557 controls) followed by multiple levels of replication of the association using a total of ∼5,000 subjects (2,092 cases and 3,114 controls). Through these staged association studies followed by resequencing and linkage disequilibrium mapping, we identified a single nucleotide polymorphism (SNP), rs7605378 associated with osteoporosis. (combined P = 1.51×10−8, odds ratio = 1.25). This SNP is in a previously unknown gene on chromosome 2q33.1, FONG. FONG is predicted to encode a 147 amino-acid protein with a formiminotransferase domain in its N-terminal (FTCD_N domain) and is ubiquitously expressed in various tissues including bone. Our findings would give a new insight into osteoporosis etiology and pathogenesis
Monte-Carlo Simulator and Ancillary Response Generator of Suzaku XRT/XIS System for Spatially Extended Source Analysis
We have developed a framework for the Monte-Carlo simulation of the X-Ray
Telescopes (XRT) and the X-ray Imaging Spectrometers (XIS) onboard Suzaku,
mainly for the scientific analysis of spatially and spectroscopically complex
celestial sources. A photon-by-photon instrumental simulator is built on the
ANL platform, which has been successfully used in ASCA data analysis. The
simulator has a modular structure, in which the XRT simulation is based on a
ray-tracing library, while the XIS simulation utilizes a spectral
"Redistribution Matrix File" (RMF), generated separately by other tools.
Instrumental characteristics and calibration results, e.g., XRT geometry,
reflectivity, mutual alignments, thermal shield transmission, build-up of the
contamination on the XIS optical blocking filters (OBF), are incorporated as
completely as possible. Most of this information is available in the form of
the FITS (Flexible Image Transport System) files in the standard calibration
database (CALDB). This simulator can also be utilized to generate an "Ancillary
Response File" (ARF), which describes the XRT response and the amount of OBF
contamination. The ARF is dependent on the spatial distribution of the
celestial target and the photon accumulation region on the detector, as well as
observing conditions such as the observation date and satellite attitude. We
describe principles of the simulator and the ARF generator, and demonstrate
their performance in comparison with in-flight data.Comment: 19 pages with 8 figures, accepted for publication in PASJ Vol 58,
Suzaku special issu
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