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

Decker, G.; Singh, Om V.

doi:10.1103/physrevstab.2.112801

Cited by 12 publications

(7 citation statements)

References 3 publications

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“…(The symmetry is slightly broken by the use of Decker distortion in the user sectors 1-35 [3], a feature that any upgrade must retain since it reduces backgrounds on x-ray beam position monitors.) Each sector has ten quadrupoles, seven sextupoles, and eight steering magnets per plane.…”

Section: Aps Upgrade Lattice Alternativesmentioning

confidence: 99%

Multi-objective direct optimization of dynamic acceptance and lifetime for potential upgrades of the Advanced Photon Source.

Borland¹,

Sajaev²,

Emery³

et al. 2010

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The Advanced Photon Source (APS) is a 7 GeV storage ring light source that has been in operation for well over a decade. In the near future, the ring may be upgraded, including changes to the lattice such as provision of several long straight sections (LSS). Because APS beamlines are nearly fully built out, we have limited freedom to place LSSs in a symmetric fashion. Arbitrarilyplaced LSSs will drastically reduce the symmetry of the optics and would typically be considered unworkable. We apply a recently-developed multi-objective direct optimization technique that relies on particle tracking to compute the dynamic aperture and Touschek lifetime. We show that this technique is able to tune sextupole strengths and select the working point in such a way as to recover the dynamic and momentum acceptances. We also show the results of experimental tests of lattices developed using these techniques.

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Section: Aps Upgrade Lattice Alternativesmentioning

confidence: 99%

Multi-objective direct optimization of dynamic acceptance and lifetime for potential upgrades of the Advanced Photon Source.

Borland¹,

Sajaev²,

Emery³

et al. 2010

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“…After our initial measurement, several girders were intentionally moved to reduce the background signal from the x-ray beam position monitor (BPM) [4]. In May 2000, when we simply re-installed the previously used setting of the dispersion-bump lattice, we could not store enough single-bunch current for the measurement.…”

Section: Measurement Without Dispersion Bumpmentioning

confidence: 99%

Measurement of the longitudinal microwave instability in the APS storage ring

Chae

Emery²,

Lumpkin³

et al.

PACS2001. Proceedings of the 2001 Particle Accelerator Conference (Cat. No.01CH37268)

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We studied a longitudinal, single-bunch instability in the Advanced Photon Source (APS) storage ring. Previous measurements showed significant bunch lengthening without a comparable growth in energy spread [1]. Because the small dispersion at a bending magnet source point made it difficult to resolve the small change in the energy spread, we adjusted the lattice to make a dispersion bump within a sector, providing a large dispersion at the source point. The enhanced component from dispersion allowed us to measure the energy spread with greater accuracy. We observed anomalous growth in the energy spread beyond a threshold current of 7.2 mA with an rf voltage of 9.4 MV. The energy spread increased from 9.0E-4 to 9.8E-4 above the threshold current up to 10 mA. We also observed the appearance of the coherent signal at four times the synchrotron frequency beyond the threshold current, which indicates that the growth in energy spread is caused by a longitudinal instability.

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“…Before the insertion device X-BPMS can be used for orbit feedback, the X-BPM blade's contamination due to background stray radiation must be eliminated or minimized. Recently, a method for reducing X-ray background signals from ID X-ray BPMs [4] has been implemented at two sectors (out of 40 sectors) at the APS storage ring. This method involves the introduction of a chicane into the accelerator lattice that directs unwanted background radiation away from the X-ray BPM blades.…”

Section: Introductionmentioning

confidence: 99%

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

Cited by 12 publications

References 3 publications

Multi-objective direct optimization of dynamic acceptance and lifetime for potential upgrades of the Advanced Photon Source.

Multi-objective direct optimization of dynamic acceptance and lifetime for potential upgrades of the Advanced Photon Source.

Measurement of the longitudinal microwave instability in the APS storage ring

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

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