Author: Mochihashi, A.
Paper Title Page
MOPTS017 Status of Operation With Negative Momentum Compaction at KARA 878
 
  • P. Schreiber, T. Boltz, M. Brosi, B. Härer, A. Mochihashi, A.-S. Müller, A.I. Papash, M. Schuh
    KIT, Karlsruhe, Germany
 
  Funding: We are supported by the DFG-funded ’Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology’ and European Union’s Horizon 2020 research and innovation programme (No 730871)
For future synchrotron light source development novel operation modes are under investigation. At the Karlsruhe Research Accelerator (KARA) an optics with negative momentum compaction has been proposed, which is currently under commissioning. In this context, the collective effects expected in this regime are studied with an initial focus on the head-tail instability and the micro-bunching instability resulting from CSR self-interaction. In this contribution, we will present the proposed optics and the status of implementation for operation in the negative momentum compaction regime as well as a preliminary discussion of expected collective effects.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPTS017  
About • paper received ※ 14 May 2019       paper accepted ※ 20 May 2019       issue date ※ 21 June 2019  
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TUPGW016 New Operation Regimes at the Storage Ring KARA at KIT 1422
 
  • A.I. Papash, E. Blomley, T. Boltz, M. Brosi, E. Bründermann, S. Casalbuoni, J. Gethmann, E. Huttel, B. Kehrer, A. Mochihashi, A.-S. Müller, R. Ruprecht, M. Schuh, J.L. Steinmann
    KIT, Karlsruhe, Germany
 
  The storage ring Karlsruhe Research Accelerator (KARA) at KIT operates in a wide energy range from 0.5 to 2.5 GeV. Initially, the ring was designed to serve as a Light Source for synchrotron radiation facility ANKA. Since then different operation modes have been implemented at KARA: in particular, the double bend achromat (DBA) lattice with non-dispersive straight sections, the theoretical minimum emittance (TME) lattice with distributed dispersion, and different versions of low compaction factor optics with highly stretched dispersion function. Short bunches of a few ps pulse width are available at KARA. Low alpha optics have been tested and implemented in a wide operational range of the ring and are now routinely used at 1.3 GeV for studies of CSR-induced beam dynamics and THz bursting in the micro-bunching instability. Different non-linear effects, in particular, residual high order components of magnetic fields generated in insertion devices have been studied and cured. A new operation mode at high vertical tune implemented at KARA essentially improves beam performance during user operation as well as at low alpha regimes.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPGW016  
About • paper received ※ 23 April 2019       paper accepted ※ 22 May 2019       issue date ※ 21 June 2019  
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WEPTS016 Longitudinal Beam Manipulation by RF Phase Modulation at the Karlsruhe Research Accelerator 3123
 
  • A. Mochihashi, E. Blomley, T. Boltz, E. Huttel, B. Kehrer, A.-S. Müller, M. Schuh
    KIT, Karlsruhe, Germany
  • D. Teytelman
    Dimtel, San Jose, USA
 
  At the storage ring KARA (Karlsruhe Research Accelerator) of the Karlsruhe Institute of Technology (KIT) we have installed a function for the RF phase modulation to the low-level RF system. By choosing proper conditions of the modulation, the electron distribution on the longitudinal phase space can be changed in a large range. There are several applications of this longitudinal manipulation to the accelerator operation: an improvement of the beam lifetime and suppression of collective instabilities. We have performed tracking simulations for the longitudinal beam manipulation by the RF phase modulation. The results have implied that the longitudinal phase space distribution strongly depends on the modulation frequency. We have also performed experiments, which aimed at improving the beam lifetime in 2.5 GeV KARA multi-bunch operations. In this contribution, the low-level RF system at KARA, the simulation and experimental results under the RF phase modulation will be presented. As one of the options of the modulation, we consider manipulation of the internal fine structure in the longitudinal phase space by the modulation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPTS016  
About • paper received ※ 15 May 2019       paper accepted ※ 23 May 2019       issue date ※ 21 June 2019  
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