Orbit feedback at the NSLS

Singh, Om V.; Tang, Y.; Krinsky, S.

doi:10.1016/s0168-9002(98)00909-7

Cited by 4 publications

(4 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For it is designed to have a very small beam sizes both in the vertical and horizontal plane and it is required that the beam position stability is in the order of tens of µm. In order to the achieve this strict beam position requirement and keep the beam travel in the defined closed orbit range, fast orbit feedback system (FOFB) has to be utilized [2].…”

Section: Introductionmentioning

confidence: 99%

Design of Digital Fast Corrector Power Supply for TPS Storage Ring

Chien¹,

Wang²,

Wong³

et al. 2016

Proceedings of the 2016 International Conference on Energy, Power and Electrical Engineering

View full text Add to dashboard Cite

TPS (Taiwan Photon Source) is a 3rd generation synchrotron light source, which is aimed to provide high brightness beam source for various novel scientific researches. Beginning from the start of 2016, to improve the beam orbit stability, fast orbit feedback system (FOFB) is installed and tested to eliminate undesired disturbances from various sources. The FOFB system consists of fast corrector magnets, power supplies, beam position data and orbit compensation algorithm to suppress the beam orbit instability. The preliminary study has shown FOFB system is effective in stabilizing the beam position This paper describes a new type full-digital corrector power supply to serve as the driving source to feed the fast corrector magnet in the FOFB system, where both wide bandwidth and fast transient response are needed. The new power supply employs the same power stage of the analog fast corrector power supply, the current output regulation is redesigned and implemented in NI-sbRIO9606, which embeds a real-time processor and a userreconfigurable FPGA (Field Programmable Gate Array) on a single module from National Instruments. The simulation and prototype result indicates that the new power supply can deliver operational bandwidth at about 10 KHz and faster transient behavior compared to the along version of the fast corrector power supply.

show abstract

Section: Introductionmentioning

confidence: 99%

Design of Digital Fast Corrector Power Supply for TPS Storage Ring

Chien¹,

Wang²,

Wong³

et al. 2016

Proceedings of the 2016 International Conference on Energy, Power and Electrical Engineering

View full text Add to dashboard Cite

show abstract

“…In the early 80s, local feedbacks based on analog electronics were put in all of the X-ray ring insertion device beamlines [1]. Later, a global orbit correction principle was pioneered at NSLS [2] which eventually resulted in analog global feedback system installation in both the X-ray and VUV rings [3].…”

Section: History and Motivationmentioning

confidence: 99%

“…The analog systems had a bandwidth of 120 Hz [3], limited by the 30-60 Hz bandwidth of the correctors installed outside of the 4 mm wall thick aluminum vacuum chamber. To match this bandwidth without extreme complexities in the digital controller the sampling rate should be 30-50 times higher [7].…”

Section: System Design Trade-offsmentioning

confidence: 99%

“…To calculate the trim settings at each feedback cycle we use an SVD response matrix inversion algorithm which is now widely used in real time orbit feedback systems [3]- [6]. To make the closed loop system stable, the SVD correction is calculated after applying a digital filter to the measured orbit which sets the system gain and defines the dynamic behavior.…”

Section: System Layout and Correction Principlesmentioning

confidence: 99%

See 1 more Smart Citation

Fast digital orbit feedback systems at NSLS

Podobedov

Kushner

Ramamoorthy³

et al.

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

View full text Add to dashboard Cite

We are implementing digital orbit feedback systems to replace the analog ones in both the VUV and the X-ray rings. We developed an original VME-based design which is run by a powerful Motorola 2305 CPU and consists entirely of off-the-shelf VME boards. This makes the system inexpensive and easy to configure, and allows for high digitizing rates. The new 5 kHz digital global feedback system is currently operational in the VUV ring, and the X-ray system is in the commissioning phase. Some of the parameters achieved include vertical correction bandwidth of 200 Hz (at DC gain of 100) and typical orbit drift over a fill of <3% of the rms beam size. In this paper we discuss the system architecture, implementation and performance. HISTORY AND MOTIVATIONNSLS is a synchrotron light user facility providing radiation to a large number of the X-ray and VUV ring users. Although both rings generally provide high quality beam, as with any accelerator, they are prone to environmental noise creating a nuisance to some users. Main sources of noise include NSLS and AGS booster operation, floor vibrations due to water pumps and other equipment, and powerline noise at harmonics of 60 Hz. There is also a gradual orbit drift over a fill mainly caused by the mechanical motion of ring components under variable heat load. To combat these, from very early on, the NSLS had a vigorous program to improve orbit stability. In the early 80s, local feedbacks based on analog electronics were put in all of the X-ray ring insertion device beamlines [1]. Later, a global orbit correction principle was pioneered at NSLS [2] which eventually resulted in analog global feedback system installation in both the X-ray and VUV rings [3].While generally providing good stability, present analog systems have some limitations. Most importantly, they use a limited number of BPMs and corrector magnets (trims). This results in good control only at certain locations of each ring. Since the analog design is not easily scalable, it would be an enormous effort to expand the system. In addition, analog architecture is not flexible enough in the choice of system configuration, correction algorithms, filters, etc.With the progress in digital electronics it was realized that a digital design can effectively address all of these issues. A prototype global digital feedback system operating at 550 Hz was built and tested at the X-ray ring, proving a clear advantage of a digital design [4]. It demonstrated a significant reduction in the long term orbit drift compared Work supported by US DOE under contract DE-AC02-98CH10886 y E-mail: boris@bnl.gov to the analog systems in operation, as well as a much better correction of 1.2 Hz harmonics of NSLS booster noise. However, due to its low sampling rate this "old digital system" could not match the bandwidth of the analog systems and it was never put to regular operation. This is why, as the next step in improving orbit stability, we decided to build a much faster digital orbit feedback system. To date both the X-ray and the...

show abstract

Performance of the closed orbit feedback systems with spatial model mismatch

Mirza

Singh

Forck

et al. 2020

Phys. Rev. Accel. Beams

View full text Add to dashboard Cite

Closed orbit feedback (COFB) systems used for the global orbit correction rely on the pseudo-inversion of the orbit response matrix (ORM). A mismatch between the model ORM used in the controller and the actual machine ORM can affect the performance of the feedback system. In this paper, the typical sources of such model mismatch such as acceleration ramp ORM variation, intensity-dependent tune shift and beta beating are considered in simulation studies. Their effect on the performance and the stability margins are investigated for both the slow and fast regimes of a COFB system operation. The spectral radius stability condition is utilized instead of the small gain theorem to arrive at the theoretical limits of COFB stability and comparisons with simulations for SIS18 of GSI and experiments at the Cooler synchrotron (COSY) in the Forschungzentrum J ülich (FZJ) are also presented.

show abstract

Orbit feedback at the NSLS

Cited by 4 publications

References 6 publications

Design of Digital Fast Corrector Power Supply for TPS Storage Ring

Design of Digital Fast Corrector Power Supply for TPS Storage Ring

Fast digital orbit feedback systems at NSLS

Performance of the closed orbit feedback systems with spatial model mismatch

Contact Info

Product

Resources

About