ICALEPCS2013 - List of Authors (Schmidt, Ch.)

Paper

Title

Page

Superconducting Cavity Quench Detection and Prevention for the European XFEL

1239

J. Branlard, V. Ayvazyan, O. Hensler, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Cichalewski
TUL-DMCS, Łódź, Poland

Due to its large scale, the European X-ray Free Electron Laser accelerator (XFEL) requires a high level of automation for commissioning and operation. Each of the 800 superconducting RF cavities simultaneously running during normal operation can occasionally quench, potentially tripping the cryogenic system and resulting into machine down-time. A fast and reliable quench detection system is then a necessity to rapidly detect individual cavity quenches and take immediate action, thus avoiding interruption of machine operation. In this paper, the mechanisms implemented in the low level RF system (LLRF) to prevent quenches and the algorithms developed to detect if a cavity quenches anyways are explained. In particular, the different types of cavity quenches and the techniques developed to identify them are shown. Experimental results acquired during the testing of XFEL cryomodules prototypes at DESY are presented, demonstrating the performance and efficiency of this machine operation and cavity protection tool.

THPPC121

Feedbacks and Automation at the Free Electron Laser in Hamburg (FLASH)

1345

R. Kammering, Ch. Schmidt
DESY, Hamburg, Germany

For many years a set of historically grown Matlab scripts and tools have been used to stabilize transversal and longitudinal properties of the electron bunches at the FLASH. Though this Matlab-based approach comes in handy when commissioning or developing tools for certain operational procedures, it turns out to be quite tedious to maintain on the long run as it often lacks stability and performance e.g. in feedback procedures. To overcome these shortcomings of the Matlab-based approach, a server-based C++ solution in the DOOCS* framework has been realized at FLASH. Using the graphical UI designer jddd** a generic version of the longitudinal feedback has been implemented and put very fast into standard operation. The design uses sets of monitors and actuators plus their coupling which easily be adapted operation requirements. The daily routine operation of this server-based FB implementation has proven to offer a robust, well maintainable and flexible solution to the common problem of automation and control for such complex machines as FLASH and will be well suited for the European XFEL purposes.
* see e.g. http://doocs.desy.de
** see e.g. http//jddd.desy.de

Poster THPPC121 [9.473 MB]

THPPC122

High Performance and Low Latency Single Cavity RF Control Based on MTCA.4

1348

Ch. Schmidt, Ł. Butkowski, M. Hoffmann, H. Schlarb
DESY, Hamburg, Germany
M. Grzegrzółka, I. Rutkowski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

The European XFEL project at DESY requires a very precise RF control, fulfilling the objectives of high performance FEL generation. Within the MTCA.4 based hardware framework a LLRF system has been designed to control multi-cavity applications, require large processing capabilities. A generic software structure allows to apply the same design also for single-cavity applications, reducing efforts for maintenance. It has be demonstrated that the MTCA.4 based LLRF controller development achieves XFEL requirement in terms of amplitude and phase control. Due to the complexity of the signal part, which is not essential for a single cavity regulation an alternative framework has been developed, to minimize processing latency which is especially for high bandwidth applications very important. This setup is based on a fast processing advanced mezzanine card (AMC) combined with a down-converter and vector-modulator rear transition module (RTM). Within this paper the system layout and first measurement results are presented, demonstrating capabilities not only for LLRF specific applications.

FRCOBAB02

Ultra-fast Longitudinal Feedbacks for the European XFEL

H. Schlarb, S. Pfeiffer, Ch. Schmidt
DESY, Hamburg, Germany

Free Electron Lasers, like the European XFEL, a 3.5 km long accelerator complex under construction in Hamburg, put stringent demands on the stabilization and the control of the electron beam properties. The pulsed superconducting RF accelerator of the European XFEL can provide more than thirty thousand Angstrom wavelength laser pulses per second to various types of X-ray user experiments. Ideally, these laser pulses have constant properties from shot-to-shot, such as central wavelength, duration, arrival-time and intensity. However, to meet these goals, multiple slow- and fast-feedback loops acting on the RF system have to operate in concert. In this paper, the new MTCA.4 based hardware architecture, MIMO FPGA feedback algorithm, and the cascaded feedback architecture based on RF-signals and beam based measurements relative to a femtosecond synchronization system is presented.

Slides FRCOBAB02 [3.633 MB]

Paper	Title	Page
THPPC072	Superconducting Cavity Quench Detection and Prevention for the European XFEL	1239
	J. Branlard, V. Ayvazyan, O. Hensler, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Cichalewski TUL-DMCS, Łódź, Poland
	Due to its large scale, the European X-ray Free Electron Laser accelerator (XFEL) requires a high level of automation for commissioning and operation. Each of the 800 superconducting RF cavities simultaneously running during normal operation can occasionally quench, potentially tripping the cryogenic system and resulting into machine down-time. A fast and reliable quench detection system is then a necessity to rapidly detect individual cavity quenches and take immediate action, thus avoiding interruption of machine operation. In this paper, the mechanisms implemented in the low level RF system (LLRF) to prevent quenches and the algorithms developed to detect if a cavity quenches anyways are explained. In particular, the different types of cavity quenches and the techniques developed to identify them are shown. Experimental results acquired during the testing of XFEL cryomodules prototypes at DESY are presented, demonstrating the performance and efficiency of this machine operation and cavity protection tool.

THPPC121	Feedbacks and Automation at the Free Electron Laser in Hamburg (FLASH)	1345
	R. Kammering, Ch. Schmidt DESY, Hamburg, Germany
	For many years a set of historically grown Matlab scripts and tools have been used to stabilize transversal and longitudinal properties of the electron bunches at the FLASH. Though this Matlab-based approach comes in handy when commissioning or developing tools for certain operational procedures, it turns out to be quite tedious to maintain on the long run as it often lacks stability and performance e.g. in feedback procedures. To overcome these shortcomings of the Matlab-based approach, a server-based C++ solution in the DOOCS* framework has been realized at FLASH. Using the graphical UI designer jddd** a generic version of the longitudinal feedback has been implemented and put very fast into standard operation. The design uses sets of monitors and actuators plus their coupling which easily be adapted operation requirements. The daily routine operation of this server-based FB implementation has proven to offer a robust, well maintainable and flexible solution to the common problem of automation and control for such complex machines as FLASH and will be well suited for the European XFEL purposes. * see e.g. http://doocs.desy.de ** see e.g. http//jddd.desy.de
	Poster THPPC121 [9.473 MB]

THPPC122	High Performance and Low Latency Single Cavity RF Control Based on MTCA.4	1348
	Ch. Schmidt, Ł. Butkowski, M. Hoffmann, H. Schlarb DESY, Hamburg, Germany M. Grzegrzółka, I. Rutkowski Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	The European XFEL project at DESY requires a very precise RF control, fulfilling the objectives of high performance FEL generation. Within the MTCA.4 based hardware framework a LLRF system has been designed to control multi-cavity applications, require large processing capabilities. A generic software structure allows to apply the same design also for single-cavity applications, reducing efforts for maintenance. It has be demonstrated that the MTCA.4 based LLRF controller development achieves XFEL requirement in terms of amplitude and phase control. Due to the complexity of the signal part, which is not essential for a single cavity regulation an alternative framework has been developed, to minimize processing latency which is especially for high bandwidth applications very important. This setup is based on a fast processing advanced mezzanine card (AMC) combined with a down-converter and vector-modulator rear transition module (RTM). Within this paper the system layout and first measurement results are presented, demonstrating capabilities not only for LLRF specific applications.

FRCOBAB02	Ultra-fast Longitudinal Feedbacks for the European XFEL
	H. Schlarb, S. Pfeiffer, Ch. Schmidt DESY, Hamburg, Germany
	Free Electron Lasers, like the European XFEL, a 3.5 km long accelerator complex under construction in Hamburg, put stringent demands on the stabilization and the control of the electron beam properties. The pulsed superconducting RF accelerator of the European XFEL can provide more than thirty thousand Angstrom wavelength laser pulses per second to various types of X-ray user experiments. Ideally, these laser pulses have constant properties from shot-to-shot, such as central wavelength, duration, arrival-time and intensity. However, to meet these goals, multiple slow- and fast-feedback loops acting on the RF system have to operate in concert. In this paper, the new MTCA.4 based hardware architecture, MIMO FPGA feedback algorithm, and the cascaded feedback architecture based on RF-signals and beam based measurements relative to a femtosecond synchronization system is presented.
	Slides FRCOBAB02 [3.633 MB]