DIPAC2011 - List of Authors (Lund-Nielsen, J.)

Paper

Title

Page

Sensitivity Optimization of the Standard Beam Current Monitors for XFEL and FLASH II

197

M. Werner, J. Lund-Nielsen, Re. Neumann, N. Wentowski
DESY, Hamburg, Germany

There is a tendency to operate 4th generation SASE driven light sources at very low charge in order to further shorten the pulse length. Therefore the operation range of XFEL and FLASH II was extended to a charge range of as low as 20 pC to 1 nC. For a reliable charge measurement down to 20 pC, a low noise design of the signal chain from the monitor head to the digitizing ADC is necessary. This paper describes the steps taken in order to increase the sensitivity and dynamic range of the monitors currently used in the FLASH accelerator, and the basic theoretical background will be explained. Finally, first results are presented.

Poster MOPD65 [0.768 MB]

WEOC03

Dark Current Monitor for the European XFEL

572

D. Lipka, W. Kleen, J. Lund-Nielsen, D. Nölle, S. Vilcins, V. Vogel
DESY, Hamburg, Germany

Dark current is produced due from field emission in the accelerator. This generates a radiation background in the tunnel which damages the electronics and activates components. To decrease the dark current different methods like kickers and collimators are used. To control the dark current level and measure and optimize the efficiency of dark current reduction dark current monitors are required. To measure the dark current a cavity was designed and built with the operation frequency of the accelerator. Here the small charge of the dark current present in every RF bucket induces and superimposes a field up to a measurable level. The cavity is proven at the PITZ facility. In addition to dark current levels down to 50 nA, the monitor allows for charge measurements resolution below pC, better than the Faraday cup. In addition the ratio of amplitudes from higher order monopole modes is a function of the bunch length. Measurements show the same trend of bunch length compared with a destructive streak camera method with comparable resolution. Therefore this monitor is able to measure bunch charge, dark current and bunch length in a non-destructive manner.

Slides WEOC03 [0.935 MB]

Paper	Title	Page
MOPD65	Sensitivity Optimization of the Standard Beam Current Monitors for XFEL and FLASH II	197
	M. Werner, J. Lund-Nielsen, Re. Neumann, N. Wentowski DESY, Hamburg, Germany
	There is a tendency to operate 4th generation SASE driven light sources at very low charge in order to further shorten the pulse length. Therefore the operation range of XFEL and FLASH II was extended to a charge range of as low as 20 pC to 1 nC. For a reliable charge measurement down to 20 pC, a low noise design of the signal chain from the monitor head to the digitizing ADC is necessary. This paper describes the steps taken in order to increase the sensitivity and dynamic range of the monitors currently used in the FLASH accelerator, and the basic theoretical background will be explained. Finally, first results are presented.
	Poster MOPD65 [0.768 MB]

WEOC03	Dark Current Monitor for the European XFEL	572
	D. Lipka, W. Kleen, J. Lund-Nielsen, D. Nölle, S. Vilcins, V. Vogel DESY, Hamburg, Germany
	Dark current is produced due from field emission in the accelerator. This generates a radiation background in the tunnel which damages the electronics and activates components. To decrease the dark current different methods like kickers and collimators are used. To control the dark current level and measure and optimize the efficiency of dark current reduction dark current monitors are required. To measure the dark current a cavity was designed and built with the operation frequency of the accelerator. Here the small charge of the dark current present in every RF bucket induces and superimposes a field up to a measurable level. The cavity is proven at the PITZ facility. In addition to dark current levels down to 50 nA, the monitor allows for charge measurements resolution below pC, better than the Faraday cup. In addition the ratio of amplitudes from higher order monopole modes is a function of the bunch length. Measurements show the same trend of bunch length compared with a destructive streak camera method with comparable resolution. Therefore this monitor is able to measure bunch charge, dark current and bunch length in a non-destructive manner.
	Slides WEOC03 [0.935 MB]