120142226
Polarization of recoil neutrons from single-pion photoproduction off protons in the resonance region
Abstract The polarization of the recoil neutrons from the reaction γ p→ π + n was measured at a c.m. angle of 105° for incident photon energies between 675 and 1125 MeV. A scattered π + meson and a recoil neutron were detected in coincidence with a magnetic spectrometer and a neutron polarimeter system using liquid hydrogen. Results are compared with recent phenomenological analyses and the other existing data measured by the double polarization measurement technique.
121021517
A honeycomb sandwich structure vacuum jacket for cryogenic targets
Abstract Cryogenic targets (H 2 , D 2 and 4 He) have been built for use in the study of photonuclear reactions with a π sr spectrometer, TAGX, at the 1.3 GeV Tokyo electron synchrotron. A new type of vacuum jacket, fabricated from plastic honeycomb core and Mylar skins, has been used in the target system for more than 5000 hours. The average radiation thickness and the average density of this jacket are measured to be 3.3 × 10 −3 X 0 and 0.15 g/cm 3 , respectively.
119906527
MEASUREMENT OF THE POLARIZATION PARAMETER IN BACKWARD $pi$$sup +$p ELASTIC SCATTERING AT 1.60, 1.80, 2.11, AND 2.31 GeV/c.
3231612
Neutral-pion photoproduction on the deuteron.
Large-angle cross sections for ..gamma..d..--> pi../sup 0/d are systematically measured in a photon energy range between 500 and 1000 MeV. A good fit is obtained by use of a Glauber model calculation which includes the dibaryon resonances /sup 3/F/sub 3/(2.26) and /sup 1/G/sub 4/(2.51), but the fit has an unusual nature in the role of resonance and nonresonance contributions.
123100999
Differential cross sections of neutral pion photoproduction from hydrogen in the energy region from 390 MeV to 975 MeV
The differential cross sections of the reaction γp→π0p have been measured at photon energies between 390 MeV and 975 MeV with an energy step of 20 or 25 MeV. The angular region covers 11 angles between 15° and 130° in the c.m.s. A combination of a magnetic spectrometer and photon detector was used for the measurement in the angular region from 50° to 130°. At forward angles of 15°, 35° and 50°, π0 mesons were detected using a π0 detector consisting of a pair of photon detectors. The data obtained with two different detection systems overlap at the angle of 50° and coincide with each other within the experimental error. The results are compared with those of phenomenological partial-wave analyses.
121673805
Polarimeter System for High-Energy Protons Using Carbon Plate and Liquid Hydrogen
In order to measure recoil proton polarization for the reaction γ+p→π°+p in a wide energy range, a polarimeter system has been constructed using carbon plate and liquid hydrogen as the scatterer. It consists of multi-wire proportional chambers, wire spark chambers, scintillation counter hodoscopes, and scatterers. Carbon plates for lower energy protons and liquid hydrogen for higher-energy protons were used as scatterers. The liquid-hydrogen polarimeter has worked reliably in continuous operation for a long time. The performance of the system in the experiment is described.
118539083
Simultaneous resonant excitation of low-frequency eccentric wave and tilt wave on tidally deformed disks
Simultaneous excitation of low-frequency eccentric precessing mode (one-armed p-mode) and tilt mode on tidally deformed disks is considered. If the orbit of the secondary star is eccentric and its orbital plane is misaligned with the disk plane of the primary, the above-mentioned two low-frequency oscillation modes are simultaneously excited on the primary disk, the former having prograte precession and the latter having retrograde precession. This excitation of disk oscillations is due to a wave–wave resonant excitation process considered by Kato (2013, PASJ, 65, 75). If parameter values relevant to Be/X-ray binary systems are adopted, the periods of these excited oscillations are around 10 times the orbital period of the secondary, which may be comparable with the timescale of giant outbursts observed in Be/X-ray systems.
15439880
Lattice analysis of the KEKB colliding rings
A low beta lattice with /spl beta/x*//spl beta/y*=100/1 cm has been realized in the KEKB colliding rings. The basic optical parameters have been measured and compared with the model.
55762967
Application of Electrochemical Buffing onto Niobium SRF Cavity Surface
Niobium electropolishing for SRF cavities are generally considered to be the best technology today. However, hydrofluoric and sulfuric acid mixture usually used in the EP process is harmful and requires us carefully controlled handling of it and the many additional facilities. In this article, we propose a new application of electrochemical buffing (ECB) to niobium SRF cavity. In the method of ECB, a rotating disk with abrasive fine particles where electrolyte is supplied is pressed against the workpiece. The disk and the work function as a cathode and an anode, respectively and an aqueous solution of sodium nitrate is used for the electrolyte. This technology brings us a couple of remarkable advantages like high etching rate, ultra small surface roughness, cost-effective and environment-compatible polishing.
122772838
Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider
A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti/Cu conductor to be operated at 1.8 K in pressurized super fluid helium, The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split/symmetric coil/collar design for twin aperture dipoles. A design central magnetic field of 10 tesla has been successfully achieved in excitation at 1.95 K in pressurized superfluid helium. Test results of the magnet with a summary of the design and fabrication are presented.
108290141
Thermal Instability of Advection-Dominated Disks against Local Perturbations
The thermal stability of advection-dominated accretion disks against local perturbations is re-examined in order to correct some errors in our previous paper. Thermal perturbations which are local in the radial direction are found to also be local in the vertical direction. Because of this, the using of vertically integrated quantities was irrelevant in analyzing the stability of local thermal perturbations when the disks are geometrically thick. Our new results, obtained by correcting the error, show that if the turbulence acts as a diffusion process in thermal energy transport, it strongly dampens the thermal perturbations. In these cases when the diffusion process is weak, however, perturbations grow due to a variation of the viscous heating associated with the perturbations. One such example of growth is in the case where radiation pressure greatly dominates the gas pressure.