IPAC2017 - List of Authors (Grecki, M.K.)

Paper	Title	Page
TUPIK052	Fast Automatic Ramping of High Average Power Guns	1809
	Y. Renier DESY Zeuthen, Zeuthen, Germany M.K. Grecki, O. Hensler, S. Pfeiffer DESY, Hamburg, Germany
	The electron guns at PITZ, FLASH and European XFEL are standing wave structures which operate at high average power (>40 kW) to produce long trains of high quality beams. This amount of power heats the cavity surface enough to change signi'cantly the gun resonance frequency. As consequence, to keep the re'ection low, the RF power ramp must be enough slow to permit the water cooling system to keep the gun temperature close to the set-point. Also, as the temperature probe sits close to the surface of the iris, the required gun temperature set-point to maintain the gun on resonance is a function of the average power. The RF power ramping is a difficult process in which temperature and re'ection must be monitored to adjust accordingly the temperature set-point and the ramping speed of the RF power. An automatic software to adjust the RF frequency and the temperature set-point of the PITZ gun in parallel to the RF power ramping has been developed. The use of this software has signi'cantly reduced the time spent to start up the gun or to recover from interlocks, increasing the time spent at nominal parameters which would also be very important for user facilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK052
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THOAA3	Installation and First Commissioning of the LLRF System for the European XFEL	3638
	J. Branlard, G. Ayvazyan, V. Ayvazyan, Ł. Butkowski, M. Fenner, M.K. Grecki, M. Hierholzer, M. Hoffmann, M. Killenberg, D. Kostin, D. Kühn, F. Ludwig, D.R. Makowski, U. Mavrič, M. Omet, S. Pfeiffer, H. Pryschelski, K.P. Przygoda, A.T. Rosner, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, B. Szczepanski, G. Varghese, H.C. Weddig, R. Wedel, M. Wiencek, B.Y. Yang DESY, Hamburg, Germany W. Cichalewski, F. Makowski, A. Mielczarek, P. Perek TUL-DMCS, Łódź, Poland K. Czuba, P.K. Jatczak, T.P. Leśniak, K. Oliwa, D. Sikora, M. Urbański, W. Wierba Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland A.S. Nawaz TUHH, Hamburg, Germany
	The installation phase of the European X-ray free laser electron laser (XFEL) is finished, leaving place for its commissioning phase. This contribution summarizes the low-level radio frequency (LLRF) installation steps, illustrated with examples of its challenges and how they were addressed. The commissioning phase is also presented, with a special emphasis on the effort placed into developing LLRF automation tools to support the commissioning of such a large scale accelerator. The first results of the LLRF commissioning of the XFEL injector and first RF stations in the main linac are also given.
	Slides THOAA3 [15.800 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THOAA3
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THPAB103	On-Line RF Amplitude and Phase Calibration	3957
	M.K. Grecki, V. Ayvazyan, J. Branlard, M. Hoffmann, M. Omet, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany
	The accelerating RF field has crucial importance on the beam properties. It is not only used just to accelerate particles but also to shape the bunches at bunch compressors. It is really important to control and measure the field as seen by the beam while usually only indirect (not using the beam) field measurements are available*. Since they are affected by many contributions the measurements must be always calibrated to the beam. Usually this calibration is performed at special operating conditions that prevents normal operation of the accelerator. During normal operation the calibrations is assumed to not drift which is certainly not perfectly true and introduce some control errors. The paper shows how to extract the RF-beam calibration from RF signals during normal operating condition (when RF feed-back, beam loading compensation, learning feed-forward etc. are active). All the algorithms and computations were performed on signals recorded at FLASH accelerator but the main idea is general and can be used at other locations as well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB103
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Fast Automatic Ramping of High Average Power Guns

1809

Y. Renier
DESY Zeuthen, Zeuthen, Germany
M.K. Grecki, O. Hensler, S. Pfeiffer
DESY, Hamburg, Germany

The electron guns at PITZ, FLASH and European XFEL are standing wave structures which operate at high average power (>40 kW) to produce long trains of high quality beams. This amount of power heats the cavity surface enough to change signi'cantly the gun resonance frequency. As consequence, to keep the re'ection low, the RF power ramp must be enough slow to permit the water cooling system to keep the gun temperature close to the set-point. Also, as the temperature probe sits close to the surface of the iris, the required gun temperature set-point to maintain the gun on resonance is a function of the average power. The RF power ramping is a difficult process in which temperature and re'ection must be monitored to adjust accordingly the temperature set-point and the ramping speed of the RF power. An automatic software to adjust the RF frequency and the temperature set-point of the PITZ gun in parallel to the RF power ramping has been developed. The use of this software has signi'cantly reduced the time spent to start up the gun or to recover from interlocks, increasing the time spent at nominal parameters which would also be very important for user facilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPIK052

Export •

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

THOAA3

Installation and First Commissioning of the LLRF System for the European XFEL

3638

J. Branlard, G. Ayvazyan, V. Ayvazyan, Ł. Butkowski, M. Fenner, M.K. Grecki, M. Hierholzer, M. Hoffmann, M. Killenberg, D. Kostin, D. Kühn, F. Ludwig, D.R. Makowski, U. Mavrič, M. Omet, S. Pfeiffer, H. Pryschelski, K.P. Przygoda, A.T. Rosner, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, B. Szczepanski, G. Varghese, H.C. Weddig, R. Wedel, M. Wiencek, B.Y. Yang
DESY, Hamburg, Germany
W. Cichalewski, F. Makowski, A. Mielczarek, P. Perek
TUL-DMCS, Łódź, Poland
K. Czuba, P.K. Jatczak, T.P. Leśniak, K. Oliwa, D. Sikora, M. Urbański, W. Wierba
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
A.S. Nawaz
TUHH, Hamburg, Germany

The installation phase of the European X-ray free laser electron laser (XFEL) is finished, leaving place for its commissioning phase. This contribution summarizes the low-level radio frequency (LLRF) installation steps, illustrated with examples of its challenges and how they were addressed. The commissioning phase is also presented, with a special emphasis on the effort placed into developing LLRF automation tools to support the commissioning of such a large scale accelerator. The first results of the LLRF commissioning of the XFEL injector and first RF stations in the main linac are also given.

Slides THOAA3 [15.800 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THOAA3

Export •

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

THPAB103

On-Line RF Amplitude and Phase Calibration

3957

M.K. Grecki, V. Ayvazyan, J. Branlard, M. Hoffmann, M. Omet, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

The accelerating RF field has crucial importance on the beam properties. It is not only used just to accelerate particles but also to shape the bunches at bunch compressors. It is really important to control and measure the field as seen by the beam while usually only indirect (not using the beam) field measurements are available*. Since they are affected by many contributions the measurements must be always calibrated to the beam. Usually this calibration is performed at special operating conditions that prevents normal operation of the accelerator. During normal operation the calibrations is assumed to not drift which is certainly not perfectly true and introduce some control errors. The paper shows how to extract the RF-beam calibration from RF signals during normal operating condition (when RF feed-back, beam loading compensation, learning feed-forward etc. are active). All the algorithms and computations were performed on signals recorded at FLASH accelerator but the main idea is general and can be used at other locations as well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB103

Export •

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