# | First Name | Last Name | Institution | Country | List |
44 | Hitoshi | Tanaka | JASRI/SPring-8 | Japan | |
Oral Presentation #1: |
Session: Facility Reports |
Title #1: Present Status of Orbit Stability at SPring-8 |
Abstract: We have started so called "top-up operation" at SPring-8 since May this year. It is well known that this operation keeps the thermal equilibrium of vacuum chambers the inside atmosphere of the tunnel and X-ray beam optics. However due to the peculiar condition of SPring-8 the drastic improvement has not seen on beam orbit stability. On the other hand the top-up oeration reveals a new perturbation source which was burried in the noisy variation during the original non-top-up operation. We will be reporting the present status of the SPring-8 orbit stability especially focusing on the problems we are now facing to. |
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Oral Presentation #2: |
Session: Noise Source Suppression |
Title #2: New Approach to Correction of COD Caused by ID parameter Change |
Abstract: We have developed a scheme for precisely correcting orbit variation caused by a dipole error-field of an insertion device (ID). For the precise correction extraction of a “real response” i.e. beam orbit variation by a change of the ID error-field is the key. To this end over a measurement period changeable parameters during an experiment a gap and a phase of ID are periodically changed with a mirror symmetric pattern. This operation modulates the real response measured by a couple of conventional wide frequency-band detectors. The real response is thus extracted precisely by adequate averaging and filtering procedures. Furthermore the mirror symmetric pattern enables us to separately extract the orbit variation by a static error field and that by a dynamic one e.g. an induced field by the dynamical change of the ID gap or phase. We built a real time measurement system with a sampling rate of 100Hz and applied the scheme to correct the orbit variation caused by the error-field of an APPLE–II type undulator installed in the SPring-8 storage ring. The obtained result shows that the developed scheme markedly improves the correction performance and can suppress the orbit variation by the ID error-field down to the level of one micron. |
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