Author: Shang, H.
Paper Title Page
MOPPP057 Optimization of the Low-emittance Lattice of the APS Booster Synchrotron 690
 
  • C. Yao, V. Sajaev, N. Sereno, H. Shang
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06- CH11357.
The APS booster is a 7GeV electron synchrotron. Three lattices have been originally designed with a nominal beam emittance of 132, 109, and 92 nm, respectively. In the past we have mostly operated the booster with the 132 nm lattice because of its better stability. The lower-emittance lattices are not utilized. In early 2010 we upgraded the booster ramp correction and reduced the 360Hz current ripples of the ramp supplies. Current ramp errors have been significantly reduced. This raises our interest in running the low- emittance lattice to improve APS storage ring injection efficiency and reduce radiation losses. This report presents the optimization methods and measurement results of booster beam performance of the booster 92nm lattice.
 
 
MOPPP058 Improvements to the APS Booster Injection Controllaw Process 693
 
  • C. Yao, F. Lenkszus, H. Shang, S. Xu
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under contract No. DE-AC02-06- CH11357.
The APS booster is a 7-GeV electron synchrotron with a 0.5-second cycle time. The booster runs a set of injection control programs that corrects the injection beam trajectory based on the beam history of two BPMs. An IOC process calculates the I and Q components of beam oscillation from turn-by turn beam position samples over the first 64 turns. The booster injection control programs apply phase, energy, and transverse angle correction based on the result of the IOC processing. The initial system was installed in 2007. Since installation the system has mostly worked well for normal user operations. However, occasionally the system has yielded inconsistent results. Recently we reviewed the signal and processes involved in this system and made necessary upgrades to some components, including selection of a new set of two input BPMs, optimization of FFT parameters, and addition of an injection tune control program. These upgrades have significantly improved the effectiveness and consistency of the system. We report the findings, analysis, and results.
 
 
TUPPP034 BPM Gains and Beta Function Measurement Using MIA and FPGA BPMs at the APS 1686
 
  • C.-X. Wang, G. Decker, H. Shang, C. Yao
    ANL, Argonne, USA
  • D. Ji
    IHEP, Beijing, People's Republic of China
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The broadband BPM system at the Advanced Photon Source (APS) is being upgraded with FPGA-based beam history modules, which fix problems in the old history modules and increase functionality. Using these new turn-by-turn BPMs and the newly developed real-time feedback system, measurement of BPM gains, beta function and other optics functions are being developed based on model-independent analysis of turn-by-turn data and model fitting, aiming at quasi-real-time and high-accuracy optics measurement. We will discuss our effort, especially experience with strong nonlinearity and wakefields typical of 3rd-generation light sources.
 
 
WEPPP070 Simulation of the APS Storage Ring Orbit Real-Time Feedback System Upgrade Using MATLAB 2870
 
  • S. Xu, G. Decker, R.I. Farnsworth, F. Lenkszus, H. Shang, X. Sun
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source (APS) storage ring orbit real-time feedback (RTFB) system plays an important role in stabilizing the orbit of the stored beam. An upgrade is planned that will improve beam stability by increasing the correction bandwidth to 200 Hz or higher. To achieve this, the number of available steering correctors and beam position monitors (BPMs) will be increased, and the sample rate will be increased by an order of magnitude. An additional benefit will be the replacement of aging components. Simulations have been performed to quantify the effects of different system configurations on performance.
 
 
WEPPR084 Measurement of Coherent Damping Rate of the APS Storage Ring 3126
 
  • C. Yao, K.C. Harkay, H. Shang, C.-X. Wang
    ANL, Argonne, USA
 
  Funding: Work supported by U.S. Department of Energy, Offices of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The APS storage ring is a 7-GeV electron storage ring with a single-bunch current of up to 16 mA during normal user operations. To overcome beam instability we employ both chromatic correction and bunch-by- bunch feedback system. Typically we run a chromaticity of 4 for a 24-single fill pattern and 9 for a hybrids fill pattern in both planes with the feedback system loops closed. The APS upgrade (APS-U) calls for a beam current of 150 mA and installation of vertical deflecting cavities for short X-ray (SPX) production. In order to estimate whether the current chromatic correction and feedback system are adequate for the upgrade, we performed coherent damping rate measurements with two methods: kicking the beam with a kicker pulse and exciting the beam with the feedback system. We conclude that with a chromaticity of 4 in both planes, we can achieve a damping rate of 3 kHz in the x- plane and 2 kHz in the y-plane with feedback loops closed. Similar damping rates can also be achieved with chromatic correction alone. A special fitting program was developed to perform the damping rate analysis. This report presents the measurement data and results of the analysis.