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To obtain position-stabilized photon beams from the Photon Factory storage ring, our efforts were concentrated on two directions, one to minimize any disturbances causing the stored beam to move, and the other to suppress undesired beam motion by using feedback systems. This paper concerns one of the most disturbing cases, the diurnal beam position drift. The drift motion was suppressed with a global orbit feedback system, so that photon beam position was kept stable at all the beamlines. At the same time, some disturbances were reduced by investigating the cause and the mechanism of beam motion. The fact that the beam drift motion was closely correlated to the outdoor temperature variations led us to make a model simulation by taking account of the meteorological conditions around the building. It was proved that the building distortion due to the external thermal stress resulted in the diurnal beam motion. To minimize such distortion, it is suggested that one should insulate the building on the rooftop rather than underneath it as is usually done. [ABSTRACT FROM AUTHOR]

A multiundulator, Revolver No. 19, was constructed and installed at the straight section (B 18-B19) of the 2.5-GeV Photon Factory storage ring. The mechanical structure of Revolver No. 19 consists of a main frame and two rotatable beams with four base plates, on which undulator magnets with four different lengths of period are mounted. A pair of undulator magnets with a desired period length can be selected by revolving the rotatable beams. The energy range of the radiation covered by fundamental peaks from the undulator magnets is from 7.8 to 1150eV. [ABSTRACT FROM AUTHOR]

The photon beam radiating from the position-stabilized storage ring tended to show large vertical drift at some beamlines. It had earlier been pointed that the beam drift might be due to the local floor displacement which was caused by the thermal distortion of the storage ring building. An estimate of the floor displacement was made by using a simulation model which takes into account the thermal stress due to the sunbeam heating of the buildings, and it seemed to give an explanation for the amount of photon-beam displacement. This raised a question whether the local floor movement is fully responsible for the apparent displacement of the photon beam. Detailed study was primarily earned out for beamline 4. First, the level of the beamline was surveyed and found to be small compared with the amount of beam displacement actually observed. Second, when beam displacement was measured with respect to two independent frames of reference located at the upstream and downstream ends of the beamline, no difference was found between the two. Both the level survey and the displacement measurement led us to conclude that the large photon-beam drift, was produced not by the local floor movement, but by the beam itself. [ABSTRACT FROM AUTHOR]