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Mitsuhashi, T.

Paper Title Page
MOPLT069 Investigation of Injection for the Low-emittance Lattice with New-6.25 ohm Kicker Magnet System at the Photon Factory 710
 
  • A. Ueda, K. Harada, Y. Kobayashi, T. Mitsuhashi
    KEK, Ibaraki
 
  We installed 6.25ohm traveling-wave kicker magnet in the Photon Factory to obtain a wide acceptance for the injected beam into the low-emittance lattice of the Photon Factory. We investigate the injection for the low-emittance lattice with this 6.25ohm kicker magnet system. Hence we have optical beam diagnostic systems which source point is inside of injection bump, we use this system for the investigation of injection. The pulse shape of the injection bump was measured by the optical beam profile monitor with high-speed gated camera by using a stored beam. The result of pulse shape of injection bump was agreed with the predicted one by using result of magnetic field measurement, and pulse duration was shorter than twice of revolution time. The instantaneous beam profile of injected beam was observed in turn by turn by using the same beam profile monitor system. We measure the turn by turn position of the injected beam from this observation and compare with a simulation. We also observe a smear out of beam oscillation by nonlinear effect from this instantaneous beam profile measurement.  
WEPKF043 Measurement of the Vertical Quadrupolar Tune Shift in the Photon Factory Storage Ring 1702
 
  • S. Sakanaka, T. Mitsuhashi, T. Obina
    KEK, Ibaraki
 
  We measured the frequencies of vertical quadrupole oscillations in the 2.5-GeV Photon Factory storage ring at KEK. The measured vertical quadrupole tunes showed remarkable dependence of about -7.5E-5/mA on the bunch current. This contrasts with our previous result of about +4.8E-5/mA (presented in PAC2003) for the horizontal quadrupole tune shift. These results will suggest that the transverse wake forces in a quadrupolar mode contribute significantly to the transverse motions of particles in the Photon Factory storage ring.  
THPLT070 Design and Constriction of Coronagraph for Observation of Beam Halo 2652
 
  • T. Mitsuhashi
    KEK, Ibaraki
 
  The coronagraph is a spatial telescope to observe the sun-corona by artificial eclipse. The concept of this apparatus is to realize the Schlieren-optical system for cutting the bright diffraction fringes in order to observe a less-bright object surrounding the main image such as the sun-corona. We applied this concept for the observation of the surrounding structure (halo, tail) of the beam. Since the background is mainly scattered light come from the objective lens, the key point to observe a less-intense object is to reduce scattering light from objective lens. We used a very well-polished lens (better than scratch and dig 20/20) as objective lens, and succeeded to obtain the signal to background ratio better than 10-5. As a test, we tried to observe the tail of beam by hiding the central peak with artificial eclipse by the coronagraph at Photon Factory storage ring. We succeeded to observe the tail of beam which has an intensity range of 1/104 of the peak intensity.