SRF2013 - List of Authors (Grecki, M.K.)

Paper	Title	Page
THP048	The Influence of Tuners and Temperature on the Higher Order Mode Spectrum for 1.3 GHz SCRF Cavities	1016
	R. Ainsworth Royal Holloway, University of London, Surrey, United Kingdom N. Baboi, M.K. Grecki, T. Wamsat DESY, Hamburg, Germany N. Eddy Fermilab, Batavia, USA S. Molloy ESS, Lund, Sweden P. Zhang CERN, Geneva, Switzerland
	Higher Order Modes are of concern for superconducting cavities as they can drive instabilities and so are usually damped and monitored. With special dedicated electronics, HOMs can provide information on the position on the beam. It has been proposed that piezo tuners used to keep the cavities operating at 1.3 GHz could alter the HOM spectrum altering the calibration constants used to read out the beam position affecting long term stability of the system. Also, of interest is how the cavity reacts to the slow tuner. Detuning and the retuning the cavity may alter the HOM spectrum. This is of particular interest for future machines not planning to use dedicated HOM damping as the tuning procedure may shift the frequency of HOMs onto dangerous resonances. The effect of temperature on the HOM spectrum is also investigated. An investigation of these effects has been performed at FLASH and the results are presented including numerical simulations used to predict the resulting cavity distortion.

THP085	Equipping FLASH with MTCA.4-based LLRF System	1126
	J. Branlard, V. Ayvazyan, Ł. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig DESY, Hamburg, Germany W. Cichalewski, D.R. Makowski, A. Piotrowski TUL-DMCS, Łódź, Poland K. Czuba, I. Rutkowski, D. Sikora, Ł. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland I.M. Kudla NCBJ, Świerk/Otwock, Poland K. Oliwa, W. Wierba IFJ-PAN, Kraków, Poland
	The Free-Electron Laser in Hamburg (FLASH) is now equipped with a MicroTCA-based (MTCA.4) low-level radio frequency (LLRF) system, to replace the previous VME system and to serve as a test bench for the European X-ray Free Electron Laser (XFEL) LLRF system. This paper presents details on the new FLASH LLRF system setup, including installations inside the radiation prone tunnel environment. The benefits and preliminary results of the newly installed system are also given.

THP087	LLRF Tests of XFEL Cryomodules at AMTF: First Experimental Results	1132
	J. Branlard, V. Ayvazyan, M.K. Grecki, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Cichalewski, K. Gnidzińska, A. Piotrowski, K.P. Przygoda TUL-DMCS, Łódź, Poland W. Jałmużna Embedded Integrated Control Systems GmbH, Hamburg, Germany
	In preparation for the series production of cryomodules for the European X-ray Free Electron Laser (XFEL), three pre-series cryomodules and several prototypes have been produced and tested at the Cryomodule Test Bench (CMTB) and at the Accelerating Module Test Facility (AMTF) in DESY. Among the numerous tests performed on the modules, the low-level radio frequency (LLRF) tests aim at characterizing the performance of the modules from an RF controls perspective. These integration tests must take into account cavity tuners, cavity motorized couplers, quench gradients, microphonics, piezo control and the overall gradient performance of the cryomodule under test. In this paper, the LLRF-specific tests are summarized and the first experimental results obtained at CMTB and AMTF are presented.

Paper

Title

Page

The Influence of Tuners and Temperature on the Higher Order Mode Spectrum for 1.3 GHz SCRF Cavities

1016

R. Ainsworth
Royal Holloway, University of London, Surrey, United Kingdom
N. Baboi, M.K. Grecki, T. Wamsat
DESY, Hamburg, Germany
N. Eddy
Fermilab, Batavia, USA
S. Molloy
ESS, Lund, Sweden
P. Zhang
CERN, Geneva, Switzerland

Higher Order Modes are of concern for superconducting cavities as they can drive instabilities and so are usually damped and monitored. With special dedicated electronics, HOMs can provide information on the position on the beam. It has been proposed that piezo tuners used to keep the cavities operating at 1.3 GHz could alter the HOM spectrum altering the calibration constants used to read out the beam position affecting long term stability of the system. Also, of interest is how the cavity reacts to the slow tuner. Detuning and the retuning the cavity may alter the HOM spectrum. This is of particular interest for future machines not planning to use dedicated HOM damping as the tuning procedure may shift the frequency of HOMs onto dangerous resonances. The effect of temperature on the HOM spectrum is also investigated. An investigation of these effects has been performed at FLASH and the results are presented including numerical simulations used to predict the resulting cavity distortion.

THP085

Equipping FLASH with MTCA.4-based LLRF System

1126

J. Branlard, V. Ayvazyan, Ł. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig
DESY, Hamburg, Germany
W. Cichalewski, D.R. Makowski, A. Piotrowski
TUL-DMCS, Łódź, Poland
K. Czuba, I. Rutkowski, D. Sikora, Ł. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
I.M. Kudla
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The Free-Electron Laser in Hamburg (FLASH) is now equipped with a MicroTCA-based (MTCA.4) low-level radio frequency (LLRF) system, to replace the previous VME system and to serve as a test bench for the European X-ray Free Electron Laser (XFEL) LLRF system. This paper presents details on the new FLASH LLRF system setup, including installations inside the radiation prone tunnel environment. The benefits and preliminary results of the newly installed system are also given.

THP087

LLRF Tests of XFEL Cryomodules at AMTF: First Experimental Results

1132

J. Branlard, V. Ayvazyan, M.K. Grecki, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Cichalewski, K. Gnidzińska, A. Piotrowski, K.P. Przygoda
TUL-DMCS, Łódź, Poland
W. Jałmużna
Embedded Integrated Control Systems GmbH, Hamburg, Germany

In preparation for the series production of cryomodules for the European X-ray Free Electron Laser (XFEL), three pre-series cryomodules and several prototypes have been produced and tested at the Cryomodule Test Bench (CMTB) and at the Accelerating Module Test Facility (AMTF) in DESY. Among the numerous tests performed on the modules, the low-level radio frequency (LLRF) tests aim at characterizing the performance of the modules from an RF controls perspective. These integration tests must take into account cavity tuners, cavity motorized couplers, quench gradients, microphonics, piezo control and the overall gradient performance of the cryomodule under test. In this paper, the LLRF-specific tests are summarized and the first experimental results obtained at CMTB and AMTF are presented.