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- Y. Shimosaki, K. Fukami, K.K. Kaneki, K. Kobayashi, M. Masaki, C. Mitsuda, T. Nakamura, T. Nakanishi, H. Ohkuma, M. Oishi, M. Shoji, K. Soutome, S. Takano, M. Takao
JASRI/SPring-8, Hyogo-ken, Japan
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The machine tuning of a new optics is in progress at the SPring-8 storage ring, in order not only to provide brilliant photons for current users but also to study a strategy of a lattice design and a tuning scenario for the upgrade project SPring-8 II. The natural emittance is reduced to 2.4 nmrad from the present value of 3.4 nmrad without any change of magnet positions. The flux density 1.3 times higher than the present was observed at the diagnostics beamline. The nominal injection efficiency of the order of 80 % has been achieved (the present: 92 %) by correcting the error of the optics function, by adjusting the strength of the injection magnets and by optimizing the sextupole magnetic fields. The beam lifetime was 13 h at 1 mA / bunch (the present: 22 h), and the momentum aperture estimated from the measurement of the Touschek lifetime was 2.3 % (the present: 2.8 %). Though these are tolerable to the user operation, further optimization of the sextupoles is ongoing. After verifying the photon beam performance at beamlines, this new optics will be applied to the user operation. The optics design and its beam performance will be presented in detail.
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