Horizontal movement of the storage ring floor at the Photon Factory

At the Photon Factory, the storage ring with an elliptic shape varies its size due to heat generated from many accelerator components and beamline instruments packed in the ring building as well as due to solar irradiation and atmospheric heat. We continuously measured the major axis length of the ring with a laser interferometer, and also measured temperatures at the building roof slab and on two floors of ring tunnel and experimental hall. It was found that the long-term variation in the major axis length is well reproduced by a computer simulation.<
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