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[en] The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets

[en] The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets

No abstract available

[en] The recent upgrade of the NSLS X-Ray Ring energy from 2.584 to 2.8 GeV requires defocusing sextupole fields beyond the operating limits of the present sextupole magnets. We have demonstrated that the required fields can be achieved by addition of permanent magnets to counteract the saturation in the magnet poles. Magnetic measurements on a NSLS sextupole agree with fields predicted by Radia

[en] Aiming at the completion of TRISTAN colliding beam complex, the laboratory engaged in the construction works throughout this year. Following the commissioning of a high current 200 MeV electron linac for positron production and of a 250 MeV positron linac in April, positrons were successfully accelerated through the existing electron linac and the accumulation ring in October. On March 21, 1986, the electron-position collision in the accumulation ring was observed in its first trial at 5 GeV with a luminosity of about 10²⁸/cm²s. The main ring accelerator tunnel, four experimental halls and other associated buildings were completed in this fiscal year. Each of the TRISTAN experimental groups has engaged in the construction of its own detector complex, aiming at the completion of the system by the spring of 1987. In particular, large superconducting solenoid magnets were successfully operated in the test. A large computer system with FACOM M382s for TRISTAN data analysis was commissioned in October. It is the serious concern to establish safety measures for the whole TRISTAN project. The positron beam accelerated by the existing 2.5 GeV electron linac was also fed to the Photon Factory storage ring. The 12 GeV proton synchrotron started the experiment on hadron science from the beginning of this fiscal year after one year shutdown. (Kako, I.)

[en] This year, the scientific achievement of KEK was successful very much. After the dedication ceremony of TRISTAN on April 6 and 7, 1987, experimental physics run was started on May 13, and 26 GeV beam was supplied for e⁺e^- collision. In all four experiments, that is, the collaboration of three major detectors, AMY, TOPAZ and VENUS, and a fancy experiment for searching high ionizing particles, SHIP, the good physics data were collected. During the summer shutdown, the rf power was boosted, and the TRISTAN is operated at 28 GeV from the beginning of 1988. All experimental groups have made great progress in their detector performances including large superconducting solenoids and sophisticated computer systems. The test operation of a superconducting rf cavity system was successful, and the installation of 16 units of 5-cell Nb cavities is planned, aiming at achieving 30 GeV/beam by the end of 1988. The 12 GeV PS was operated for about 4,000h. Its main experiment changed to nuclear physics, particularly studies on hypernuclei. As the application of high energy accelerators to other fields, the use of the spallation neutron source, the pulsed muon source and the medical use of proton beam have been carried out. In the Photon Factory, the brightness of photon beam was remarkably improved. (K.I.)

[en] NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT FOR PERIOD, OCTOBER 1, 1998 THROUGH SEPTEMBER 30, 1999