Author: Lenkszus, F.
Paper Title Page
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.
 
 
TUOAB01 Timing and Synchronization for the APS Short Pulse X-ray Project 1077
 
  • F. Lenkszus, N.D. Arnold, T.G. Berenc, G. Decker, E.M. Dufresne, R.I. Farnsworth, Y.L. Li, R.M. Lill, H. Ma
    ANL, Argonne, USA
  • J.M. Byrd, L.R. Doolittle, G. Huang, R.B. Wilcox
    LBNL, Berkeley, California, 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 Short-Pulse X-ray (SPX) project, which is part of the APS upgrade, will provide intense, tunable, high-repetition-rate picosecond x-ray pulses through the use of deflecting cavities operating at the 8th harmonic of the storage-ring rf. Achieving this picosecond capability while minimizing the impact to other beamlines outside the SPX zone imposes demanding timing and synchronization requirements. For example, the mismatch between the upstream and downstream deflecting cavities' rf field phase is specified to be less than 0.077 degrees root mean squared (rms) at 2815 MHz (~77 femtoseconds). Another stringent requirement is to synchronize beamline pump-probe lasers to the SPX x-ray pulse to 400 femtoseconds rms. To achieve these requirements we have entered into a collaboration with the Beam Technology group at LBNL. They have developed and demonstrated a system for distributing stable rf signals over optical fiber capable of achieving less than 20 femtoseconds rms drift and jitter over 2.2 km over 60 hours*. This paper defines the overall timing/synchronization requirements for the SPX and describes the plan to achieve them.
* R. Wilcox et al. Opt. Let. 34(20), Oct 15, 2009
 
slides icon Slides TUOAB01 [2.515 MB]  
 
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.
 
 
WEPPC038 Status of the Short-Pulse X-ray Project at the Advanced Photon Source 2292
 
  • A. Nassiri, N.D. Arnold, T.G. Berenc, M. Borland, B. Brajuskovic, D.J. Bromberek, J. Carwardine, G. Decker, L. Emery, J.D. Fuerst, A.E. Grelick, D. Horan, J. Kaluzny, F. Lenkszus, R.M. Lill, J. Liu, H. Ma, V. Sajaev, T.L. Smith, B.K. Stillwell, G.J. Waldschmidt, G. Wu, B.X. Yang, Y. Yang, A. Zholents
    ANL, Argonne, USA
  • J.M. Byrd, L.R. Doolittle, G. Huang
    LBNL, Berkeley, California, USA
  • G. Cheng, G. Ciovati, P. Dhakal, G.V. Eremeev, J.J. Feingold, R.L. Geng, J. Henry, P. Kneisel, K. Macha, J.D. Mammosser, J. Matalevich, A.D. Palczewski, R.A. Rimmer, H. Wang, K.M. Wilson, M. Wiseman
    JLAB, Newport News, Virginia, USA
  • Z. Li, L. Xiao
    SLAC, Menlo Park, California, USA
 
  Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
The Advanced Photon Source Upgrade (APS-U) Project at Argonne will include generation of short-pulse x-rays based on Zholents’* deflecting cavity scheme. We have chosen superconducting (SC) cavities in order to have a continuous train of crabbed bunches and flexibility of operating modes. In collaboration with Jefferson Laboratory, we are prototyping and testing a number of single-cell deflecting cavities and associated auxiliary systems with promising initial results. In collaboration with Lawrence Berkeley National Laboratory, we are working to develop state-of-the-art timing, synchronization, and differential rf phase stability systems that are required for SPX. Collaboration with Advanced Computations Department at Stanford Linear Accelerator Center is looking into simulations of complex, multi-cavity geometries with lower- and higher-order modes waveguide dampers using ACE3P. This contribution provides the current R&D status of the SPX project.
* A. Zholents et al., NIM A 425, 385 (1999).
 
 
THPPC089 LLRF Control for SPX @ APS Demonstration Experiment 3491
 
  • G. Huang, J.M. Byrd, K. Campbell, L.R. Doolittle, J.B. Greer
    LBNL, Berkeley, California, USA
  • N.D. Arnold, T.G. Berenc, F. Lenkszus, H. Ma
    ANL, Argonne, USA
 
  The SPX experiment at APS is part of the APS upgrade project, using two deflecting cavity to chirp the electron pulse and then generate short pulse x-ray. To minimize the influence to other users on the storage ring, the phase synchronization of the two deflecting cavity are required to be better then 77 femto-second. A LLRF4 board based system is designed to demonstrate the capability of meeting this requirement. This paper discuss the hardware and firmware design of the demo experiment including the cavity emulator, frequency reference generation and LLRF control algorithm.