Real-time orbit feedback at the APS

Carwardine, J.; Lenkszus, F.

doi:10.1063/1.56995

Cited by 25 publications

(23 citation statements)

References 5 publications

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“…These numbers must be combined in quadrature to obtain the totals listed in the last row. At the APS, low-frequency drift motion is controlled using workstation-based orbit correction software, while intermediate-frequency motion (jitter) is corrected using real-time digital feedback operating at a 1 kHz update rate (2). Correction bandwidth presently extends to about 50 Hz.…”

Section: Sources Of Beam Motionmentioning

confidence: 99%

“…The key point to notice in Equation (2) is that the sums, whether taken in frequency or time domain, produce an invariant quantity, namely the mean square signal amplitude. The k=0 component of the sum over frequency (i.e., k) in Equation (2) has been moved to the left-hand side of the equation and is none other than the square of the mean, or DC value for the data set { x n }, as can easily be verified by inserting k = 0 into the first of Equations (1).…”

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

“…The k=0 component of the sum over frequency (i.e., k) in Equation (2) has been moved to the left-hand side of the equation and is none other than the square of the mean, or DC value for the data set { x n }, as can easily be verified by inserting k = 0 into the first of Equations (1). Power spectral density is quantitatively defined to be 2| X k | 2 / δ f, (k = 0...N/2), where δ f = 1/(N δ t) is the frequency discretization interval, δ t is the sampling period, and N is the number of samples.…”

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

“…Values of | X k | from k = N/2+1 to N-1 are just a mirror image of those from k = 1 to N/2 -1, explaining the factor of 2. "Integrating" the power spectral density from zero up the the Nyquist frequency f Ny = (N/2) δ f = 1/(2 δ t) yields the mean square signal defined in Equation (2).…”

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

See 3 more Smart Citations

Fundamental limits on beam stability at the advanced photon source

Decker¹,

Carwardine²,

Singh³

1998

AIP Conference Proceedings

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Abstract. Orbit correction is now routinely performed at the few-micron level in the Advanced Photon Source (APS) storage ring. Three diagnostics are presently in use to measure and control both AC and DC orbit motions: broad-band turn-by-turn rf beam position monitors (BPMs), narrow-band switched heterodyne receivers, and photoemission-style x-ray beam position monitors. Each type of diagnostic has its own set of systematic error effects that place limits on the ultimate pointing stability of x-ray beams supplied to users at the APS. Limiting sources of beam motion at present are magnet power supply noise, girder vibration, and thermal timescale vacuum chamber and girder motion. This paper will investigate the present limitations on orbit correction, and will delve into the upgrades necessary to achieve true sub-micron beam stability.

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Section: Sources Of Beam Motionmentioning

confidence: 99%

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

Section: Introduction: Power Spectral Densitymentioning

confidence: 99%

See 2 more Smart Citations

Fundamental limits on beam stability at the advanced photon source

Decker¹,

Carwardine²,

Singh³

1998

AIP Conference Proceedings

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“…These rf electronics are used for both dc and ac feedback with correction bandwidth up to 50 Hz [3]. Some of the many systematic effects impacting these devices are electron bunch fill pattern dependence, beam intensity dependence, and earth tidal force-induced accelerator circumference variation [4].…”

Section: Introductionmentioning

confidence: 99%

Method for reducing x-ray background signals from insertion device x-ray beam position monitors

Decker

Singh

1999

Phys. Rev. ST Accel. Beams

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X-ray BPM-based feedback system at the APS storage ring

Singh¹,

Erwin²,

Decker³

et al. 2000

AIP Conference Proceedings

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Abstract. At the Advanced Photon Source (AI%) storage ring, the X-ray beam position monitors (X-BPMS) measure accurate photon position down to the subrnicron level. This level of stable measurement has been possible due to 1) superior thermal insulation and vibration damping of the X-ray BPM support structure [1], 2) minimal dependence on the bunch pattern and intensity variations, and 3) use of uhrastable preamplifiers and processing electronics. A new X-BPM interface is under development and will be discussed here. This interface will be integrated into the existing rf-based orbit feedback systems. To study preliminary results, an experimental X-BPM orbit feedback set-up was developed and implemented in one of &e bending magnet beamlines. The results from this set-up are encouraging. For an operational fill, a typical orbit drift of 30 microns (at X-ray BPMs) has been reduced to less than 5 microns. The fill-to-fill photon orbit reproducibility has been improved from 75 microns to less than 10 microns.-

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Real-time orbit feedback at the APS

Cited by 25 publications

References 5 publications

Fundamental limits on beam stability at the advanced photon source

Fundamental limits on beam stability at the advanced photon source

Method for reducing x-ray background signals from insertion device x-ray beam position monitors

X-ray BPM-based feedback system at the APS storage ring

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