Abstract
Beam lifetime of a synchrotron is dominated by Touschek scattering. In the beamline Phase II project of Shanghai synchrotron radiation facility, a passive third harmonic cavity is to be installed for bunch lengthening and instability suppressing. In this paper, the beam dynamics of the cavity is investigated. The parameters of passive operation are optimized to cancel the slope of RF voltage and lengthen the bunches. The Touschek lifetime increases are estimated for optimum and non-optimum voltage flattening. A tolerance of the operation is studied in case that there is a shift on detuning angle. The effect caused by reduction in harmonic voltage generated by lengthened bunch distribution is also estimated using iteration method. An increase in synchrotron frequency spread due to nonlinearity of the voltage giving to the bunch is found by using tracking simulation. This spread can help in damping coupled bunch instability through Landau damping.
Similar content being viewed by others
References
G.M. Liu, Z.M. Dai, H.H. Li et al., Lattice design for SSRF storage ring. High Energy Phys. Nucl. Phys. 30, (Supp. I), 144–146 (2001). doi:10.3321/j.issn:0254-3052.2006.z1.047
B.C. Jiang, Z.T. Zhao, G.M. Liu, Study of Touschek lifetime in SSRF storage ring. High Energy Phys. Nucl. Phys. 30, 693–698 (2006)
M. Boscolo, Beam lifetime in low emittance rings, in Proceedings of IPAC2013, Shanghai, China, pp. 1574–1576 (2013)
L.H. Chang, C. Wang, M.C. Lin et al., Effects of the passive harmonic cavity on the beam bunch, in Proceedings of 2005 Particle Accelerator Conference, Knoxville, Tennessee, 3904–3906 (2005)
M. Migliorati, L. Palumbo, M. Zobov, Bunch length control in DAQNE by a higher harmonic cavity. Nucl. Instrum. Meth. A 354, 215–223 (1995)
R.A. Bosch, C.S. Hsue, Suppression of longitudinal coupled-bunch instabilities by a passive higher harmonic cavity, in Proceedings of 1993 Particle Accelerator Conference. Washington, DC, 5, pp. D3369–D3371 (1993). doi:10.1109/PAC.1993.309653
R.A. Bosch, K.J. Kleman, J.J. Bisognano, Robinson instabilities with a higher-harmonic cavity. Phys. Rev. Spec, Top-AC 4, 074401 (2001). doi:10.1103/PhysRevSTAB.4.074401
P.F. Tavares, S.C. Leemann, M. Sjostrom et al., The MAX IV storage ring project. J. Synchrotron Radiat. 21, 862–877 (2014). doi:10.1107/S1600577514011503
G. Skripka, P.F. Tavares, M. Klein et al., Transverse instabilities in the MAX IV 3 GeV ring, in Proceedings of IPAC2014, Dresden, Germany, vol. 1689–1691 (2014)
H. Fan, C.F. Wu, G.C. Liu, Calculations of operating schemes for a passive harmonic cavity in HLS-II. Chin. Phys. C 36, 895–899 (2012). doi:10.1088/1674-1137/36/9/018
M. Georgsson, Landau cavities in third generation synchrotron light sources, in Proceedings of the 2001 Particle Accelerator Conference, Chicago, IL, 4, pp. 2689–2691 (2001). doi:10.1109/PAC.2001.987874
M. Georgsson, A. Andersson, M. Eriksson, Landau cavities at MAX II. Nucl. Instrum. Meth. A 416, 465–474 (1998). doi:10.1016/S0168-9002(98)00667-6
J.M. Byrd, M. Georgsson, Lifetime increase using passive harmonic cavities in synchrotron light sources. Phys. Rev. Spec. Top-AC 4, 030701 (2001). doi:10.1103/PhysRevSTAB.4.030701
G.M. Ma, Z.T. Zhao, J.F. Liu, Design of a higher harmonic cavity for the SSRF storage ring. Chin. Phys. C 32, 275 (2008). doi:10.1088/1674-1137/32/4/007
H. Fan, C.F. Wu, L. Wang, Tracking simulations for the HLS-II with a passive harmonic cavity in the symmetric and asymmetric fill patterns. Chin. Phys. C 36, 1111–1115 (2012). doi:10.1088/1674-1137/36/11/013
A. Hofmann, S. Myers, Beam dynamics in a double RF system, in Proceedings of the 11th International Conference on High Energy Acc, CERN, Geneva, Switzerland, pp. 610–14 (1980). doi:10.1007/978-3-0348-5540-2_83
K.Y. Ng, in Passive landau cavity for the LNLS light source electron ring, FERMILAB-FN-0696 (2000)
E. Métral, Stability of the longitudinal bunched-beam coherent dipole mode, in Proceedings of APAC 2004, Gyeongju, Korea, pp. 137–139 (2004)
Author information
Authors and Affiliations
Corresponding author
Additional information
This work was supported by the National Key Research and Development Program of China (No. 2016YFA0402001).
Rights and permissions
About this article
Cite this article
Phimsen, T., Jiang, BC., Hou, HT. et al. Improving Touschek lifetime and synchrotron frequency spread by passive harmonic cavity in the storage ring of SSRF. NUCL SCI TECH 28, 108 (2017). https://doi.org/10.1007/s41365-017-0259-y
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s41365-017-0259-y