- Open Access
Detuning properties of rf phase modulation in an electron storage ring
Phys. Rev. Accel. Beams 28, 082801 – Published 11 August, 2025
DOI: https://doi.org/10.1103/t3gd-13n4
Abstract
In electron storage rings, it is possible to increase the bunch length by applying phase modulation to the radio-frequency accelerating field by choosing appropriate parameters for the modulation. Such a bunch lengthening effect improves beam parameters such as beam lifetime, which can help us achieve better beam stability. It is well known that the modulation frequency around the double synchrotron frequency is effective in lengthening the bunch. The dependence of bunch lengthening on modulation frequency, the so-called detuning property, has a peak around the double synchrotron frequency with a frequency width that depends on the modulation amplitude. Nonlinear effects due to phase modulation lead to a peak frequency shift in a negative direction from the double synchrotron frequency, accompanied by an asymmetric peak shape. Beam current also affects the properties of the detuning condition of such bunch lengthening. We investigated the detuning property using a theoretical model and systematic measurements at the electron storage ring Karlsruhe Research Accelerator, and we verified the qualitative agreement between the experiments and the theoretical model. The macroparticle simulations have confirmed the agreement.
Physics Subject Headings (PhySH)
Article Text
References (14)
- C. Bernardini, G. F. Corazza, G. Di Giugno, G. Ghigo, J. Haissinski, P. Marin, R. Querzoli, and B. Touschek, Lifetime and beam size in a storage ring, Phys. Rev. Lett. 10, 407 (1963).
- S. Sakanaka, M. Izawa, T. Mitsuhashi, and T. Takahashi, Improvement in the beam lifetime by means of an rf phase modulation at the KEK Photon Factory storage ring, Phys. Rev. ST Accel. Beams 3, 050701 (2000).
- S. Sakanaka and T. Obina, Observation of longitudinal quadrupole-mode oscillation of a bunch which were induced by RF phase modulation in the electron storage ring, Jpn. J. Appl. Phys. 40, 2465 (2001).
- N. P. Abreu, R. H. A. Farias, and P. F. Tavares, Longitudinal dynamics with rf phase modulation in the Brazilian electron storage ring, Phys. Rev. ST Accel. Beams 9, 124401 (2006).
- KIT IBPT website, https://www.ibpt.kit.edu/kara.
- M. Toda, Theory of Oscillation (Shindou-ron), New Physics Series (Shin-Butsurigaku Series) (Baifuu-Kan, Tokyo, 1968).
- Dimtel Inc., https://www.dimtel.com/.
- D. Teytelman, Phase modulation in storage-ring RF system, arXiv:1907.01381v2.
- B. Kehrer, A. Borysenko, E. Hertle, N. Hiller, M. Holz, A.-S. Müller, P. Schönfeldt, and P. Schütze, Visible light diagnostics at the ANKA storage ring, in Proceedings of 6th International Particle Accelerator Conference (JACoW, Geneva, 2015), p. 866, https://accelconf.web.cern.ch/IPAC2015/papers/mopha037.pdf.
- S. Maier, Systematic studies of RF phase modulation at KARA, Master’s thesis, Karlsruhe Institute of Technology, 2020, 10.5445/IR/1000123900.
- E. Blomley, M. Schedler, and A.-S. Müller, Beam studies with the new longitudinal feedback system at the ANKA storage ring, in Proceedings of 7th International Particle Accelerator Conference (JACoW, Geneva, 2016), p. 2658, https://accelconf.web.cern.ch/ipac2016/papers/wepor001.pdf.
- N. Zhang, B. Gao, L. Lai, and R. Yuan, Upgrade and first commissioning of transverse feedback system for SSRF, in Proceedings of 9th International Beam Instrumentation Conference (JACoW, Geneva, 2020), p. 136, https://accelconf.web.cern.ch/ibic2020/papers/wepp17.pdf.
- E. Blomley, Investigation and control of beam instabilities at the Karlsruhe research accelerator using a 3-D digital bunch-by-bunch feedback system, Ph.D. thesis, Karlsruhe Institute of Technology, 2021, 10.5445/IR/1000137621.
- A. W. Chao, Physics of Collective Beam Instabilities in High Energy Accelerators, Wiley Series in Beam Physics and Accelerator Technology (Wiley-interscience publication, New York, 1993), p. 279.
