IPAC2014 - List of Authors (Sasaki, S.)

Paper	Title	Page
MOPRO080	Fast Beam Orbit Monitoring System during Beam Abort at SPring-8 Storage Ring	274
	T. Fujita, T. Masuda, S. Sasaki JASRI/SPring-8, Hyogo, Japan H. Sumitomo SES, Hyogo-pref., Japan
	SPring-8 is a 3rd generation light source which has been operated stably. During user operation, an interlock system which turns off the RF acceleration signal if the beam orbit at insertion devices exceed a window is in operation. Beam abort events due to the interlock system have occurred as a rare event at SPring-8. Though in most cases we find trouble in accelerator devices as the source of the beam orbit shift, sometimes we cannot find any evidence after the beam abort. In order to identify the sources of such aborts, we have developed a system which observe beam orbit along the storage ring during beam abort. The system was realized by modification of the digital part of the existing COD measurement system. Every 1 ms, the system measures beam position at all BPMs with the position resolution of 1 micron or less. This system enabled us to identify the source when a beam abort due to an orbit shift with a time constant of longer than a few milliseconds. Furthermore, this system is applicable to survey sources of beam orbit fluctuations during stable operation. In this proceeding, we describe the system, beam orbit data during beam abort and source analysis.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO080
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MOPRO082	Suppression of Stored Beam Oscillation at Injection by Fast Kicker in the SPring-8 Storage Ring	280
	C. Mitsuda, K. Fukami, K. Kobayashi, M. Masaki, H. Ohkuma, S. Sasaki, K. Soutome JASRI/SPring-8, Hyogo-ken, Japan T. Nakanishi SES, Hyogo-pref., Japan
	When the injection bump orbit is not closed perfectly at the beam injection, the horizontal stored beam oscillation is excited. In the SPring-8 storage ring, many efforts had been paid to reduce the beam oscillation by adjusting the temporal shape and timing of four bump magnets and by applying a counter kick to the residual oscillation, whose amplitude is as large as 0.4mm and the width is as narrow as 500ns. Now, the averaged oscillation amplitude has successfully been suppressed to the level of less than 0.1mm. To confirm the suppression effect, we observed the turn-by-turn photon beam profile at the diagnostics beamline with the insertion device. We confirmed that the light axis oscillation was significantly suppressed by a factor of 5 comparing by applying a counter kick. We also found that the oscillation shape and the oscillation amplitude, which were caused by the timing shift of firing bump magnets, are drastically changed by only timing shift of one magnet. We are considering the feedback scheme to keep the suppression effect at the initial level during the user-time.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO082
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TUPRO092	Magnetic-field Variable Permanent Dipole Magnet for Future Light Sources	1253
	T. Watanabe, K. Fukami, T. Nakanishi, S. Sasaki JASRI/SPring-8, Hyogo, Japan
	Permanent dipole magnets with variable magnetic field have been designed, fabricated, and tested at SPring-8. Permanent magnets can be advantageous over electromagnets in terms of reliability, stability and compactness in addition to the small power consumption. No unexpected down of an accelerator due to power supply failure is supposed to happen. There is no cooling water flow that can induce a fluctuation of the magnetic field. These features may become important for future light sources, where a very reliable, stable, and compact ring is required. In addition, the power consumption is now one of the most important issues after the 3.11 disaster in Japan. One of critical issues to realize such a magnet is that a magnetic field has to be tuned. In the future, combined-functioned and longitudinally gradient magnets will play a key role in achieving extremely small emittance. In such a case, changing a gap will not work any more. We have designed and fabricated a permanent dipole magnet of which magnetic field can be tuned without changing the gap. The results of the performance test will be presented and a possibility to apply it for future light sources will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO092
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Fast Beam Orbit Monitoring System during Beam Abort at SPring-8 Storage Ring

274

T. Fujita, T. Masuda, S. Sasaki
JASRI/SPring-8, Hyogo, Japan
H. Sumitomo
SES, Hyogo-pref., Japan

SPring-8 is a 3rd generation light source which has been operated stably. During user operation, an interlock system which turns off the RF acceleration signal if the beam orbit at insertion devices exceed a window is in operation. Beam abort events due to the interlock system have occurred as a rare event at SPring-8. Though in most cases we find trouble in accelerator devices as the source of the beam orbit shift, sometimes we cannot find any evidence after the beam abort. In order to identify the sources of such aborts, we have developed a system which observe beam orbit along the storage ring during beam abort. The system was realized by modification of the digital part of the existing COD measurement system. Every 1 ms, the system measures beam position at all BPMs with the position resolution of 1 micron or less. This system enabled us to identify the source when a beam abort due to an orbit shift with a time constant of longer than a few milliseconds. Furthermore, this system is applicable to survey sources of beam orbit fluctuations during stable operation. In this proceeding, we describe the system, beam orbit data during beam abort and source analysis.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO080

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRO082

Suppression of Stored Beam Oscillation at Injection by Fast Kicker in the SPring-8 Storage Ring

280

C. Mitsuda, K. Fukami, K. Kobayashi, M. Masaki, H. Ohkuma, S. Sasaki, K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan
T. Nakanishi
SES, Hyogo-pref., Japan

When the injection bump orbit is not closed perfectly at the beam injection, the horizontal stored beam oscillation is excited. In the SPring-8 storage ring, many efforts had been paid to reduce the beam oscillation by adjusting the temporal shape and timing of four bump magnets and by applying a counter kick to the residual oscillation, whose amplitude is as large as 0.4mm and the width is as narrow as 500ns. Now, the averaged oscillation amplitude has successfully been suppressed to the level of less than 0.1mm. To confirm the suppression effect, we observed the turn-by-turn photon beam profile at the diagnostics beamline with the insertion device. We confirmed that the light axis oscillation was significantly suppressed by a factor of 5 comparing by applying a counter kick. We also found that the oscillation shape and the oscillation amplitude, which were caused by the timing shift of firing bump magnets, are drastically changed by only timing shift of one magnet. We are considering the feedback scheme to keep the suppression effect at the initial level during the user-time.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO082

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPRO092

Magnetic-field Variable Permanent Dipole Magnet for Future Light Sources

1253

T. Watanabe, K. Fukami, T. Nakanishi, S. Sasaki
JASRI/SPring-8, Hyogo, Japan

Permanent dipole magnets with variable magnetic field have been designed, fabricated, and tested at SPring-8. Permanent magnets can be advantageous over electromagnets in terms of reliability, stability and compactness in addition to the small power consumption. No unexpected down of an accelerator due to power supply failure is supposed to happen. There is no cooling water flow that can induce a fluctuation of the magnetic field. These features may become important for future light sources, where a very reliable, stable, and compact ring is required. In addition, the power consumption is now one of the most important issues after the 3.11 disaster in Japan. One of critical issues to realize such a magnet is that a magnetic field has to be tuned. In the future, combined-functioned and longitudinally gradient magnets will play a key role in achieving extremely small emittance. In such a case, changing a gap will not work any more. We have designed and fabricated a permanent dipole magnet of which magnetic field can be tuned without changing the gap. The results of the performance test will be presented and a possibility to apply it for future light sources will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO092

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)