116197080
Test results of TRISTAN insertion quadrupole magnet in superfluid Helium
523124
Development of a 56 mm aperture superconducting dipole model magnet for LHC
A 56 mm single aperture superconducting dipole model magnet, which is one of the frameworks of the LHC collaboration between KEK and CERN, has been developed. A central field of 8.65 T is provided at a load line ratio of 90% with a 5 block coil wound with NbTi superconducting cables. The magnet has a straight section of 0.8 m and a total length of 1.2 m. The distinctive features of the magnet are a magnetically symmetrical configuration being applicable to the twin aperture magnet and mechanical consideration sharing the magnetic forces with a high manganese steel collar and a horizontally split iron yoke. The magnet showed almost no training at 4.4 K. The first quench current at 1.8 K was 91% of the short sample I/sub c/ and the magnet reached a central magnetic field of 8.8 T. Finally it could be excited with the current of more than 99% of the short sample limit which corresponds to a central field of 9.63 T.
123873319
Experimental observations of the ion-related coupled bunch instability in a bunch train in TRISTAN AR
An experiment was carried out in TRISTAN AR for the search of the fast beam-ion instability (FBII). A train of 100 bunches with 2 ns spacing was stored with the help of the transverse bunch feedback system. The nitrogen gas was intentionally leaked into the inside of the vacuum duct to enhance the ion effect. The oscillation patterns were recorded by the beam position monitor system which is capable of storing the transverse position of every bunch up to 1600 turns. The spectra of the bunch oscillations were also measured by a spectrum analyzer. This paper describes the results of the experiment and also discusses the possible explanation of them in terms of the FBII.
125921586
Experiment on the fast beam-ion instability at the TRISTAN AR
17623960
Frequency Correlation of QPOs Based on a Resonantly Excited Disk-Oscillation Model
In previous papers, we have proposed a model that the high-frequency quasi-periodic oscillations (HF QPOs) observed in black-hole and neutron-star X-ray binaries are inertial-acoustic oscillations that are resonantly excited on a one-armed deformed disk by nonlinear couplings between the oscillations and the disk deformation. In this paper we show that in addition to the inertial-acoustic waves, one-armed corrugation waves are also excited in the deformed disks. They are low-frequency oscillations. We examine frequencies and their correlations among the inertial-acoustic oscillations and the corrugation waves that are excited, in order to know whether they can describe observed frequency correlations among kHz QPOs and low-frequency QPOs (LF QPOs) in neutron-star X-ray binaries. The results seem to well describe the observed correlations in Cir X-1, if we adopt $M= 1.5\sim 2.0 M_\odot$ and $a_* \sim 0.8$, where $M$ is the mass of the central star and $a_*$ is the dimensionless spin parameter of the metric. Finally, assumptions involved in this disk-oscillation model are briefly summarized and discussed.
123710203
Precise measurement of Ag KLM and KLN Auger spectra
Abstract Ag KLM and KLN Auger spectra have been measured with a momentum resolution of 0.02%. With this resolution, most of the lines in these transitions are well separated and the complex spectral structure is revealed. Energies and intensities of these lines are precisely determined and compared with the results of the theoretical calculations.
123854343
GENERATION OF HIGH-ENERGY ELECTRON BEAM BY LASER-PLASMA ACCELERATOR
An energy gain of the monoenergetic component of electrons γ were successfully increased to 25 MeV by decreasing an electron density ne to 4 × 1019cm-3 and increasing a laser power PL to 4 TW. An empirical scaling law of the energy gain of γ ∝ PL/ne was derived from the experiment. A forward scattering spectrum of the laser pulse showed anti-Stokes satellite peaks up to third-order harmonics around a second harmonic light and a Stokes satellite peak around a laser wavelength, which indicated that a wakefield was excited in a self-modulation laser wakefield regime. A density modulation of wakefield was estimated at 60 ± 10 % from intensity ratios of satellite peaks. The empirical scaling law well agrees with results obtained at other institutes by using higher laser power of 10 ~ 30 TW.
123062788
Constraints for transonic black hole accretion
Regularity conditions and global topological constraints leave some forbidden regions in the parameter space of the transonic isothermal, rotating matter onto black holes. Unstable flows occupy regions touching the boundaries of the forbidden regions. The astrophysical consequences of these results are discussed. 17 references.
14113517
Mass and Spin of GRS 1915+105 Based on a Resonance Model of QPOs
We demonstrate that the four high-frequency QPOs observed in GRS 1915+105 can be interpreted as the oscillation modes on disks that non-linearly and resonantly interact with a warp. The warp is assumed to be a lowfrequency global pattern on the disk. This identification suggests that the relevant mass, M, and spin parameter, a,