Journal of Nuclear Science, Engineering and Technology (JONSAT)
In cooperation with the Iranian Nuclear Society

Higher order modes of 100 MHz RF cavities and their effect on beam instabilities in the storage ring of Iranian Light Source Facility (ILSF)

Document Type : Scientific Note

Authors

S. Ahmadiannamin 1
M. Lamehi Rachti 1
F. Abbasi Davani 2
J. Rahighi 3

1 Physics and Accelerators School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 11365-3486, Tehran – Iran

2 Radiation Application Department, Nuclear Engineering Faculty, Shahid Beheshti University, P.O. Box: 1983963113, Tehran – Iran

3 Iranian Light Source Facility (ILSF), Institute of research in fundamental Sciences (IPM), P.O. Box: 19395-5746, Tehran – Iran

https://doi.org/10.24200/nst.2021.1166
Abstract
Increasing the current, beam lifetime and, the quality of dynamic properties of the stored electron beam in the storage ring are the important purposes of synchrotrons. One of the phenomena affecting the beam quality is the longitudinal and transverse instabilities that increase as the beam current increases. Longitudinal instability in radiofrequency cavities has the greatest impact due to the high-quality factor of their higher order modes. As a result of these modes, one electron bunch affects the next one and it has a long-range nature. Longitudinal instabilities increase the energy spread and lead to loss of the beam current and reduce the intensity of the output synchrotron radiation. Considering the current and emittance of the Iranian light source which is 400 mA and 270 picometer-radian in the final phase of project, it is important to evaluate the higher order modes and identify the most effective ones. Simulation studies using CST Studio Suit software show that there are 13 monopole modes up to 1500 MHz in the project's 100 MHz radio frequency cavity. Seven modes are dangerous, and two modes at frequencies of 624.67 and 1432.55 MHz, with shunt impedances of 70.8 and 115 kHz, are very effective and must be dealt with in all phases of commissioning.

Highlights

1. E.J. Jaeschke, et al, Synchrotron Light Sources and Free Electron Lasers: Accelerator Physics, Instrumentation and Science Applications, 2nd ed, (Springer International Publishing, Switzerland, 2016).

 

2. H. Ghasem, E. Ahmadi, F. Saeidi, In: Proceedings of 5th International Particle Accelerator Conference, Lattice design history of the Iranian Light Source Facility storage ring, (JACoW, Geneva, Switzerland, 2014), 249-251 (2014).

 

3. Kh. Sarhadi, ILSF basic design document, Technical groups, No. ILSF-B-MN-0000-POL-01-01I, (2017), (In Persian).

4. Kh. Sarhadi, ILSF basic design document, Technical groups, No. ILSF-B-RF-00S0-SPC-01-01I, (2017), (In Persian).

 

5. A. Karlsson, G. Kristensson, Microwave Theory, 2nd Ed. (Lund university, Sweden, (2014), KFS I Lund AB, Compendium. (2014).

 

6. T. Moreno, Microwave Transmission Design Data, 1st ed, (Norwood, MA, Artech House, USA, 1989)

 

7. K. Wille, Physics of Particle Accelerators: An Introduction, 1st ed, (Clarendon Press, Oxford, United Kingdom, Oxford University Press, 2001)

 

8. M. Magnuson, L. Johansson, MAX IV Conceptual Design Report (CDR), (2006).

 

9. M.S. Zisman, S Chattopadhyay, J Bisognano, ZAP User’s Manual, Berkeley, USA, University of California, (1986).

 

10. Z.T. Zhao, In: 4th OCPA Accelerator school, (Institute of Applied Physics, Shanghai, 2006), RF systems for electron storage rings.

 

11. V. Jain, U.V. Bhandarkar, et al, Nucl Instrum Meth, Estimation of higher order modes of INDUS-2 RF cavity using combined electromagnetic–thermal structural simulations, 612(2), 225 (2010).

 

12. H. Winick, In: Synchrotron Radiation Sources: A Primer, (WSPC, London, 2004), 334-340 (2004).

 

13. S.Y. Lee, Accelerator Physics, 4rd ed, (WSPC, Indiana, USA, 2018).

 

14. Computer simulation technology, CST microwave studio, Shams systems and technologies, Kingdom of Bahrain, http://sst-mea.com/cstmws.html.

 

15. Comsol, Zoetermeer, Netherlands, https://www.comsol.nl.

 

16. Ansys Hfss, Canonsburg, Pennsylvania,  https://www.ansys.com/products/electronics/ansys-hfss.

 

17. J.B. Svensson, M.S. Thesis, Characterization of higher order modes in the MAX IV active 100 MHz Cavities, Lund University, (2015).

Keywords

Higher order modes
100 MHz RF cavity
Longitudinal instabilities
Shunt impedance
1. E.J. Jaeschke, et al, Synchrotron Light Sources and Free Electron Lasers: Accelerator Physics, Instrumentation and Science Applications, 2nd ed, (Springer International Publishing, Switzerland, 2016).
 
2. H. Ghasem, E. Ahmadi, F. Saeidi, In: Proceedings of 5th International Particle Accelerator Conference, Lattice design history of the Iranian Light Source Facility storage ring, (JACoW, Geneva, Switzerland, 2014), 249-251 (2014).
 
3. Kh. Sarhadi, ILSF basic design document, Technical groups, No. ILSF-B-MN-0000-POL-01-01I, (2017), (In Persian).
4. Kh. Sarhadi, ILSF basic design document, Technical groups, No. ILSF-B-RF-00S0-SPC-01-01I, (2017), (In Persian).
 
5. A. Karlsson, G. Kristensson, Microwave Theory, 2nd Ed. (Lund university, Sweden, (2014), KFS I Lund AB, Compendium. (2014).
 
6. T. Moreno, Microwave Transmission Design Data, 1st ed, (Norwood, MA, Artech House, USA, 1989)
 
7. K. Wille, Physics of Particle Accelerators: An Introduction, 1st ed, (Clarendon Press, Oxford, United Kingdom, Oxford University Press, 2001)
 
8. M. Magnuson, L. Johansson, MAX IV Conceptual Design Report (CDR), (2006).
 
9. M.S. Zisman, S Chattopadhyay, J Bisognano, ZAP User’s Manual, Berkeley, USA, University of California, (1986).
 
10. Z.T. Zhao, In: 4th OCPA Accelerator school, (Institute of Applied Physics, Shanghai, 2006), RF systems for electron storage rings.
 
11. V. Jain, U.V. Bhandarkar, et al, Nucl Instrum Meth, Estimation of higher order modes of INDUS-2 RF cavity using combined electromagnetic–thermal structural simulations, 612(2), 225 (2010).
 
12. H. Winick, In: Synchrotron Radiation Sources: A Primer, (WSPC, London, 2004), 334-340 (2004).
 
13. S.Y. Lee, Accelerator Physics, 4rd ed, (WSPC, Indiana, USA, 2018).
 
14. Computer simulation technology, CST microwave studio, Shams systems and technologies, Kingdom of Bahrain, http://sst-mea.com/cstmws.html.
 
15. Comsol, Zoetermeer, Netherlands, https://www.comsol.nl.
 
16. Ansys Hfss, Canonsburg, Pennsylvania,  https://www.ansys.com/products/electronics/ansys-hfss.
 
17. J.B. Svensson, M.S. Thesis, Characterization of higher order modes in the MAX IV active 100 MHz Cavities, Lund University, (2015).
Journal of Nuclear Science, Engineering and Technology (JONSAT)
Volume 41, Issue 4 - Serial Number 94
December 2020
Pages 172-181

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