FEL2014 - List of Authors (Calvi, M.)

Paper

Title

Page

General Strategy for the Commissioning of the ARAMIS Undulators with a 3 GeV Electron Beam

107

M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, R. Ischebeck, L. Patthey, T. Schietinger, T. Schmidt
PSI, Villigen PSI, Switzerland

The commissioning of the first SwissFEL undulator line (Aramis) is planned for the beginning of 2017. Each undulator is equipped with a 5-axis camshaft system to remotely adjust its position in the micrometer range and a gap drive system to set K-values between 0.1 and 1.8. In the following paper the beam-based alignment of the undulator with respect to the golden orbit, the definition of look-up tables for the local correction strategy (minimization of undulator field errors), the fine-tuning of the K-values as well as the setting of the phase shifters are addressed. When applicable both electron beam and light based methods are presented and compared.

MOP041

Summary of the U15 Prototype Magnetic Performance

111

M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, C. Ozkan, T. Schmidt
PSI, Villigen PSI, Switzerland

The first undulator prototype (U15) was assembled and magnetically tested. The instrumentation and the algorithms developed for the undulator optimization are presented and a comparison among different approaches is reviewed. The magnetic measurement results before and after the installation of the vacuum components are discussed. The summary of the undulator test with 100 MeV electron beam is presented and the impact of the radiation on the magnetics is addressed.

MOP043

Magnetic Design of an Apple III Undulator for SwissFEL

116

T. Schmidt, A. Anghel, P. Boehler, M. Brügger, M. Calvi, S. Danner, P. Huber, A. Keller, M. Locher
PSI, Villigen PSI, Switzerland

In the frame of the SwissFEL project a soft x-ray line is planned in the coming years to cover the wavelength between 0.7 and 7.0nm. Based on the good experience at the SLS storage ring with Apple undulator as source of variable polarized light, Apple III type undulators are also foreseen at the SwissFEL. In this paper the design of these devices is introduced and the preliminary magnetic configuration together with the optimization strategy is presented in details.

THP059

The Laser Heater System of SwissFEL

871

M. Pedrozzi, M. Calvi, R. Ischebeck, S. Reiche, C. Vicario
PSI, Villigen PSI, Switzerland
B.D. Fell, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Short wavelength FELs are generally driven by high-brilliance photo-cathode RF-guns which generate electron beams with an uncorrelated energy spread on the order of 1 keV or less. These extremely cold beams can easily develop micro-bunching instabilities caused by longitudinal space charge forces after the compression process. This can result in a blow up of the energy spread and emittance beyond the tolerable level for SASE emission. It has been demonstrated theoretically and experimentally [1] that a controlled increase of the uncorrelated energy spread to typically a few keV is sufficient to strongly reduce the instability growth. In the laser heater system, one achieves a controlled increase of the beam energy spread by a resonant interaction of the electron beam with a transversally polarized laser beam inside of an undulator magnet. The momentum modulation resulting from the energy exchange within the undulator is consequently smeared out in the transmission line downstream of the laser heater system. In SwissFEL, the laser heater system is located after the first two S-band accelerating structures at a beam energy of 150 MeV. This paper describes the layout and the sub-components of this system.
[1] Z. Huang, et al, Phys. Rev. Special Topics – Accelerator and beams 13, 020703 (2010)

THP081

Beam Loss Monitors for the SwissFEL

C. Ozkan, M. Calvi, R. Ischebeck, D. Llorente Sancho, F. Löhl, G.L. Orlandi, P. Pollet, V. Schlott, T. Schmidt
PSI, Villigen PSI, Switzerland

There are currently three types of monitors planned for tracking and minimizing beam losses at the SwissFEL. Fiber-based loss monitors will provide information on the longitudinal loss location, help reduce losses at undulators and measure losses due to insertion of wire scanners for transverse beam profile measurements. They shall be integrated to the Machine Protection System due to their fast response capabilities. The dose deposited over time at the undulators shall be measured with RadFETs and readout using the DOSFET L-02 reader. Characterization of all three types of loss monitors have been carried out at the SwissFEL Injector Test Facility. This contribution shall provide in-depth description of the monitors along with their complete readout chain and results from the characterization studies.

Paper	Title	Page
MOP040	General Strategy for the Commissioning of the ARAMIS Undulators with a 3 GeV Electron Beam	107
	M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, R. Ischebeck, L. Patthey, T. Schietinger, T. Schmidt PSI, Villigen PSI, Switzerland
	The commissioning of the first SwissFEL undulator line (Aramis) is planned for the beginning of 2017. Each undulator is equipped with a 5-axis camshaft system to remotely adjust its position in the micrometer range and a gap drive system to set K-values between 0.1 and 1.8. In the following paper the beam-based alignment of the undulator with respect to the golden orbit, the definition of look-up tables for the local correction strategy (minimization of undulator field errors), the fine-tuning of the K-values as well as the setting of the phase shifters are addressed. When applicable both electron beam and light based methods are presented and compared.

MOP041	Summary of the U15 Prototype Magnetic Performance	111
	M. Calvi, M. Aiba, M. Brügger, S. Danner, R. Ganter, C. Ozkan, T. Schmidt PSI, Villigen PSI, Switzerland
	The first undulator prototype (U15) was assembled and magnetically tested. The instrumentation and the algorithms developed for the undulator optimization are presented and a comparison among different approaches is reviewed. The magnetic measurement results before and after the installation of the vacuum components are discussed. The summary of the undulator test with 100 MeV electron beam is presented and the impact of the radiation on the magnetics is addressed.

MOP043	Magnetic Design of an Apple III Undulator for SwissFEL	116
	T. Schmidt, A. Anghel, P. Boehler, M. Brügger, M. Calvi, S. Danner, P. Huber, A. Keller, M. Locher PSI, Villigen PSI, Switzerland
	In the frame of the SwissFEL project a soft x-ray line is planned in the coming years to cover the wavelength between 0.7 and 7.0nm. Based on the good experience at the SLS storage ring with Apple undulator as source of variable polarized light, Apple III type undulators are also foreseen at the SwissFEL. In this paper the design of these devices is introduced and the preliminary magnetic configuration together with the optimization strategy is presented in details.

THP059	The Laser Heater System of SwissFEL	871
	M. Pedrozzi, M. Calvi, R. Ischebeck, S. Reiche, C. Vicario PSI, Villigen PSI, Switzerland B.D. Fell, N. Thompson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Short wavelength FELs are generally driven by high-brilliance photo-cathode RF-guns which generate electron beams with an uncorrelated energy spread on the order of 1 keV or less. These extremely cold beams can easily develop micro-bunching instabilities caused by longitudinal space charge forces after the compression process. This can result in a blow up of the energy spread and emittance beyond the tolerable level for SASE emission. It has been demonstrated theoretically and experimentally [1] that a controlled increase of the uncorrelated energy spread to typically a few keV is sufficient to strongly reduce the instability growth. In the laser heater system, one achieves a controlled increase of the beam energy spread by a resonant interaction of the electron beam with a transversally polarized laser beam inside of an undulator magnet. The momentum modulation resulting from the energy exchange within the undulator is consequently smeared out in the transmission line downstream of the laser heater system. In SwissFEL, the laser heater system is located after the first two S-band accelerating structures at a beam energy of 150 MeV. This paper describes the layout and the sub-components of this system. [1] Z. Huang, et al, Phys. Rev. Special Topics – Accelerator and beams 13, 020703 (2010)

THP081	Beam Loss Monitors for the SwissFEL
	C. Ozkan, M. Calvi, R. Ischebeck, D. Llorente Sancho, F. Löhl, G.L. Orlandi, P. Pollet, V. Schlott, T. Schmidt PSI, Villigen PSI, Switzerland
	There are currently three types of monitors planned for tracking and minimizing beam losses at the SwissFEL. Fiber-based loss monitors will provide information on the longitudinal loss location, help reduce losses at undulators and measure losses due to insertion of wire scanners for transverse beam profile measurements. They shall be integrated to the Machine Protection System due to their fast response capabilities. The dose deposited over time at the undulators shall be measured with RadFETs and readout using the DOSFET L-02 reader. Characterization of all three types of loss monitors have been carried out at the SwissFEL Injector Test Facility. This contribution shall provide in-depth description of the monitors along with their complete readout chain and results from the characterization studies.