Requirements for RF control of TTF II FEL user facility

Ayvazyan, V.; Rehlich, K.; Simrock, Stefan

doi:10.1109/pac.2003.1289112

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…of Applied Sciences Hamburg, Germany gerwald.lichtenberg@haw-hamburg.de supply pulsed laser light with a tunable wavelength in the X-ray range (10 −10 m) and a repetition rate of maximum 4.5 MHz, [2]. To reach this short laser light wavelength, the European XFEL is operated in pulsed mode with a 10 Hz repetition rate.…”

Section: Universitymentioning

confidence: 99%

Self-organzied critical control for the European XFEL using black box parameter identification for the quench detection system

Nawaz

Pfeiffer

Lichtenberg

et al. 2016

2016 3rd Conference on Control and Fault-Tolerant Systems (SysTol)

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Abstract-The European Free Electron Laser (XFEL) consists of a large and complex plant, with many cost intensive and technological high-end components. It is therefore important that the XFEL can be operated reliably and safely using exception handling and fault detection systems. A crucial part of the system are the superconducting cavities for which especially quenches, i.e. the break down of the superconductivity have to be avoided. The paper shows the interaction of the fault detection system with the Low Level RF (LLRF) control system to maximize the field gradients. This is an example for process supervision, which can neither be classified as fault-tolerant, nor is it a reconfiguration system, but uses the result of the fault detection to operate the system at its fault critical limit. This scheme simulates a system which behaves like a selforganized critical system, and drives the process at its critical performance limit. It is therefore called Self-organized Critical Control (SOCC). The paper shows the basic set-up and quench detection methods of the European XFEL and gives an example for an application of SOCC.

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Section: Universitymentioning

confidence: 99%

Self-organzied critical control for the European XFEL using black box parameter identification for the quench detection system

Nawaz

Pfeiffer

Lichtenberg

et al. 2016

2016 3rd Conference on Control and Fault-Tolerant Systems (SysTol)

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“…The LLRF control system [1,7,8] requires information on a large number of signals and parameters which are either 0957-0233/07/082320+08$30.00 © 2007 IOP Publishing Ltd Printed in the UK • Cavity probe signal at 1300 MHz. The cavity probe signal represents a sample of the cavity field measured with an antenna which is loosely coupled to the end cell opposite the input coupler.…”

Section: Measurement and Control Signalsmentioning

confidence: 99%

Measurements for low level RF control systems

Simrock¹

2007

Meas. Sci. Technol.

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The low level RF control system for the European x-ray free electron laser, which is based on TESLA technology, requires information on a large number of signals and parameters which are either directly measurable as physical signals or must be derived from the physical signals. In most cases, calibrations are required to obtain the desired quantities. The measured signals are used in the real time feedback loops for field and resonance control, and for diagnostic purposes to support automation and exception handling. Good system models and powerful signal processors (including field programmable gate arrays and digital signal processors) combined with fast communication links allow for processing a large number of complex algorithms in real time. Several of these algorithms have been implemented at the free electron laser at Hamburg (FLASH) for evaluation and have increased the availability of the facility for user operation.

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“…The RF (radio frequency) field accelerating charged particles in accelerators has to be precisely stabilized in order to obtain the required beam parameters [1][2][3][4][5]. The requirement of a low energy spread of the beam demands a constant accelerating gradient that is stabilized by the complex LLRF (low level radio frequency) control system [6].…”

Section: Introductionmentioning

confidence: 99%

SEU-tolerant IQ detection algorithm for LLRF accelerator system

Grecki¹

2007

Meas. Sci. Technol.

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High-energy accelerators use RF field to accelerate charged particles. Measurements of effective field parameters (amplitude and phase) are tasks of great importance in these facilities. The RF signal is downconverted in frequency but keeping the information about amplitude and phase and then sampled in ADC. One of the several tasks for LLRF control system is to estimate the amplitude and phase (or I and Q components) of the RF signal. These parameters are further used in the control algorithm. The XFEL accelerator will be built using a single-tunnel concept. Therefore electronic devices (including LLRF control system) will be exposed to ionizing radiation, particularly to a neutron flux generating SEUs in digital circuits. The algorithms implemented in FPGA/DSP should therefore be SEU-tolerant. This paper presents the application of the WCC method to obtain immunity of IQ detection algorithm to SEUs. The VHDL implementation of this algorithm in Xilinx Virtex II Pro FPGA is presented, together with results of simulation proving the algorithm suitability for systems operating in the presence of SEUs.

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Requirements for RF control of TTF II FEL user facility

Cited by 3 publications

References 2 publications

Self-organzied critical control for the European XFEL using black box parameter identification for the quench detection system

Self-organzied critical control for the European XFEL using black box parameter identification for the quench detection system

Measurements for low level RF control systems

SEU-tolerant IQ detection algorithm for LLRF accelerator system

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