SRF2019 - List of Keywords (storage-ring)

Paper	Title	Other Keywords	Page
MOP035	Cryogenic Infrastructure at BESSY II – Current Installations and Future Developments	cryogenics, cavity, gun, radiation	131
	S. Heling, W. Anders, J. Heinrich, A. Hellwig, K. Janke, S. Rotterdam HZB, Berlin, Germany
	In Berlin-Adlershof the Helmholtz-Zentrum Berlin (HZB) is operating the synchrotron radiation source BESSY II. Two superconducting wave-length shifter magnets are built-in the storage ring of BESSY II which are cooled with liquid helium. Additionally several test facilities for superconducting cavities are operated at HZB needing helium at 1.8 K. The required helium is supplied by two helium liquefiers. Parallel to operation of the existing facilities the BERLinPro project will qualify as test facility for ERL science and technology. In order to guarantee the required supply with helium at different temperature levels one of the existing helium liquefiers has been relocated to the new accelerator building and the existing cryogenic infrastructure has been upgraded with a new 10 000 L dewar, three valve boxes, a cold compressor box, warm pumps and a 80 K helium system. This paper specifies the setup of the above described helium cryoplants in detail and gives insight into the challenges of development. The paper concludes with an outlook of the upcoming developments of the cryogenic infrastructure at HZB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP035
About •	paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOP063	Beam Loading in the BESSY VSR SRF Cavities	cavity, beam-loading, SRF, operation	217
	A.V. Tsakanian, H.-W. Glock, J. Knobloch, A.V. Vélez HZB, Berlin, Germany
	The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store long (ca. 15 ps) and short (ca. 1.7 ps) bunches in the storage ring at currents up to 300 mA. This challenging goal requires installation of four new 4-cell SRF cavities (2x1.5 GHz and 2x1.75 GHz) in one module for installation in a single straight. As far as we are aware of, this is the first installation of multi-cell L-Band cavities in a high-current storage ring. These cavities are equipped with newly developed waveguide HOM dampers necessary for stable operation. Up to 2 kW of HOM power must be absorbed. Operating two SRF cavities for each frequency will also enable transparent parking of the cavities for the beam. Based on wakefield theory, a technique for beam loading calculation will be presented. The expected beam loading both at 2 K and at room temperature has been analyzed to evaluate transparent parking for both situations. The presented study is performed for various BESSY II and VSR bunch filling patterns with 300 mA beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP063
About •	paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THP025	Overview of Superconducting RF Cavity Reliability at Diamond Light Source	cavity, vacuum, operation, GUI	885
	C. Christou, P. Gu, P.J. Marten, S.A. Pande, A.F. Rankin, D. Spink, L.T. Stant, A. Tropp DLS, Oxfordshire, United Kingdom
	Diamond Light Source has been providing beam for users since January 2007. The electron beam in the storage ring is normally driven by two superconducting CESR-B cavities, with two similar cavities available as spares. Day-to-day reliability of the cavities, measured by storage ring MTBF, has improved enormously over the years. A full analysis of how this improvement has been achieved is given, with particular attention paid to cavity voltage and vacuum pressure management, and the scheduling and procedure of cavity conditioning. The benefits and risks of full and partial warm-ups of the cavities are discussed, and details and impacts of cavity failure and repair are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP025
About •	paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOP035

Cryogenic Infrastructure at BESSY II – Current Installations and Future Developments

cryogenics, cavity, gun, radiation

131

S. Heling, W. Anders, J. Heinrich, A. Hellwig, K. Janke, S. Rotterdam
HZB, Berlin, Germany

In Berlin-Adlershof the Helmholtz-Zentrum Berlin (HZB) is operating the synchrotron radiation source BESSY II. Two superconducting wave-length shifter magnets are built-in the storage ring of BESSY II which are cooled with liquid helium. Additionally several test facilities for superconducting cavities are operated at HZB needing helium at 1.8 K. The required helium is supplied by two helium liquefiers. Parallel to operation of the existing facilities the BERLinPro project will qualify as test facility for ERL science and technology. In order to guarantee the required supply with helium at different temperature levels one of the existing helium liquefiers has been relocated to the new accelerator building and the existing cryogenic infrastructure has been upgraded with a new 10 000 L dewar, three valve boxes, a cold compressor box, warm pumps and a 80 K helium system. This paper specifies the setup of the above described helium cryoplants in detail and gives insight into the challenges of development. The paper concludes with an outlook of the upcoming developments of the cryogenic infrastructure at HZB.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP035

About •

paper received ※ 20 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

MOP063

Beam Loading in the BESSY VSR SRF Cavities

cavity, beam-loading, SRF, operation

217

A.V. Tsakanian, H.-W. Glock, J. Knobloch, A.V. Vélez
HZB, Berlin, Germany

The BESSY VSR upgrade of the BESSY II light source represents a novel approach to simultaneously store long (ca. 15 ps) and short (ca. 1.7 ps) bunches in the storage ring at currents up to 300 mA. This challenging goal requires installation of four new 4-cell SRF cavities (2x1.5 GHz and 2x1.75 GHz) in one module for installation in a single straight. As far as we are aware of, this is the first installation of multi-cell L-Band cavities in a high-current storage ring. These cavities are equipped with newly developed waveguide HOM dampers necessary for stable operation. Up to 2 kW of HOM power must be absorbed. Operating two SRF cavities for each frequency will also enable transparent parking of the cavities for the beam. Based on wakefield theory, a technique for beam loading calculation will be presented. The expected beam loading both at 2 K and at room temperature has been analyzed to evaluate transparent parking for both situations. The presented study is performed for various BESSY II and VSR bunch filling patterns with 300 mA beam current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-MOP063

About •

paper received ※ 22 June 2019 paper accepted ※ 30 June 2019 issue date ※ 14 August 2019

Export •

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

THP025

Overview of Superconducting RF Cavity Reliability at Diamond Light Source

cavity, vacuum, operation, GUI

885

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

Diamond Light Source has been providing beam for users since January 2007. The electron beam in the storage ring is normally driven by two superconducting CESR-B cavities, with two similar cavities available as spares. Day-to-day reliability of the cavities, measured by storage ring MTBF, has improved enormously over the years. A full analysis of how this improvement has been achieved is given, with particular attention paid to cavity voltage and vacuum pressure management, and the scheduling and procedure of cavity conditioning. The benefits and risks of full and partial warm-ups of the cavities are discussed, and details and impacts of cavity failure and repair are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2019-THP025

About •

paper received ※ 21 June 2019 paper accepted ※ 01 July 2019 issue date ※ 14 August 2019

Export •

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