SRF2017 - List of Authors (Pande, S.A.)

Paper	Title	Page
MOPB016	Operation of Diamond Superconducting RF Cavities	87
	P. Gu, C. Christou, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink DLS, Oxfordshire, United Kingdom
	The Diamond Light Source storage ring has been in operation using superconducting RF cavities since 2007. Diamond has four superconducting cavity modules with two usually installed at any one time. The four cavities perform differently in many aspects such as reliable operating parameters and time in service, with the longest in continuous service for 7 years without failure and the shortest failing after only 8 months. All Diamond superconducting RF cavities suffered many fast vacuum trips in their early years, but after many years of efforts, the performance of the cavities have now been effectively managed by weekly conditioning, partial warm-up during shut down and cavity voltage level control. We will discuss our experience with superconducting RF cavities and our future plan.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB016
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TUPB010	Multipactor Study in the Coupler Region of the Diamond SCRF Cavities	405
	S.A. Pande, C. Christou, P. Gu DLS, Oxfordshire, United Kingdom G. Burt Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	The Diamond storage ring operates with two CESR-B type Superconducting RF cavities. The cavities suffer from trips with a sudden loss of accelerating field if operated above a certain voltage. Consequently the cavities are operated at voltages up to 1.4 MV for better reliability. These cavities are iris coupled and have fixed Qext. At these lower operating voltages, the optimum condition for beam loading is satisfied at powers around 100 kW. For operation at 300 mA with two cavities, the power needed per system exceeds 200 kW. Therefore 3 stub tuners are used to lower the Qext to move the optimum condition close to 200kW. Additionally, the step due to the difference in the height of the coupling waveguide on the cavity and that of the vacuum side waveguide on the window results in a standing wave between the cavity and the window even at matched operation. The 3 stub tuner further enhances this standing wave. Numerical simulation reveals that the standing wave field from the cavity penetrates into the coupling waveguide increasing the probability of multipactor and breakdown in the coupler region. The results of multipactor simulations in this region with CST Studio are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB010
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Operation of Diamond Superconducting RF Cavities

87

P. Gu, C. Christou, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink
DLS, Oxfordshire, United Kingdom

The Diamond Light Source storage ring has been in operation using superconducting RF cavities since 2007. Diamond has four superconducting cavity modules with two usually installed at any one time. The four cavities perform differently in many aspects such as reliable operating parameters and time in service, with the longest in continuous service for 7 years without failure and the shortest failing after only 8 months. All Diamond superconducting RF cavities suffered many fast vacuum trips in their early years, but after many years of efforts, the performance of the cavities have now been effectively managed by weekly conditioning, partial warm-up during shut down and cavity voltage level control. We will discuss our experience with superconducting RF cavities and our future plan.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB016

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB010

Multipactor Study in the Coupler Region of the Diamond SCRF Cavities

405

S.A. Pande, C. Christou, P. Gu
DLS, Oxfordshire, United Kingdom
G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

The Diamond storage ring operates with two CESR-B type Superconducting RF cavities. The cavities suffer from trips with a sudden loss of accelerating field if operated above a certain voltage. Consequently the cavities are operated at voltages up to 1.4 MV for better reliability. These cavities are iris coupled and have fixed Qext. At these lower operating voltages, the optimum condition for beam loading is satisfied at powers around 100 kW. For operation at 300 mA with two cavities, the power needed per system exceeds 200 kW. Therefore 3 stub tuners are used to lower the Qext to move the optimum condition close to 200kW. Additionally, the step due to the difference in the height of the coupling waveguide on the cavity and that of the vacuum side waveguide on the window results in a standing wave between the cavity and the window even at matched operation. The 3 stub tuner further enhances this standing wave. Numerical simulation reveals that the standing wave field from the cavity penetrates into the coupling waveguide increasing the probability of multipactor and breakdown in the coupler region. The results of multipactor simulations in this region with CST Studio are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB010

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)