FEL2012 - List of Authors (Aiba, M.)

Paper	Title	Page
TUPD27	Beam-based Alignment of an X-FEL Undulator Section Utilizing Corrector Pattern	293
	M. Aiba, M. Böge PSI, Villigen PSI, Switzerland
	Beam based alignment of the undulator section is one of the delicate issues in beam commissioning and regular beam tuning of X-FEL facilities since the tolerance on the electron beam orbit straightness is tight, typically a few micro-meters rms. A new approach based on the dipole corrector strengths is under investigation for the PSI future X-FEL facility, SwissFEL. The idea is to minimize the deviation of corrector strengths, required to steer the electron beam to the beam position monitor (BPM) centres, by varying BPM positions. The beam trajectory, if there is no dipolar error, must be fully straight with no corrector excitation, where the deviation is zero, i.e. minimized. Under dipolar errors, e.g. undulator imperfections, the minimization is performed w.r.t. their average value. The procedure requires precise BBA of quadrupoles to adjacent BPM beforehand and an orbit feedback in operation. Although these preparation works require some efforts, the method is rather simple and robust. The methodology together with expected performance from analytical estimation and simulations applied to the undulator section of SwissFEL is presented.

THPD19	Technical Overview of SwissFEL Undulator Line	583
	R. Ganter, M. Aiba, H.-H. Braun, C. Calvi, A. Fuchs, P. Heimgartner, E. Hohmann, R. Ischebeck, H. Jöhri, B. Keil, N. Milas, M. Negrazus, S. Reiche, S. Sanfilippo, T. Schmidt, S. Sidorov, P. Wiegand PSI, Villigen PSI, Switzerland
	Starting after Linac 3 at z ~ 430 m (z = 0 being the gun photocathode position), the so-called Aramis Hard-X ray undulator section extends over 170 m, from the energy collimator to the electron beam dump. Electrons enter the undulator section with a maximum energy of 5.8 GeV, a slice emittance below 0.43 μm and a peak current of 3 kA with 200 pC of charge. A prototype of the in-vacuum undulator (U15) is currently under assembly. Most of the other beamline components have been designed and for some of them prototypes are already ordered (quadrupoles, beam position monitors, phase shifters, alignment quadrupoles; mechanical supports; safety components). The paper will describe how constraints like temperature drifts, stray magnetic field, wakefields, beam losses, costs are taken into account for the design of components and building (undulators are however described in details in a companion paper).

Paper

Title

Page

Beam-based Alignment of an X-FEL Undulator Section Utilizing Corrector Pattern

293

M. Aiba, M. Böge
PSI, Villigen PSI, Switzerland

Beam based alignment of the undulator section is one of the delicate issues in beam commissioning and regular beam tuning of X-FEL facilities since the tolerance on the electron beam orbit straightness is tight, typically a few micro-meters rms. A new approach based on the dipole corrector strengths is under investigation for the PSI future X-FEL facility, SwissFEL. The idea is to minimize the deviation of corrector strengths, required to steer the electron beam to the beam position monitor (BPM) centres, by varying BPM positions. The beam trajectory, if there is no dipolar error, must be fully straight with no corrector excitation, where the deviation is zero, i.e. minimized. Under dipolar errors, e.g. undulator imperfections, the minimization is performed w.r.t. their average value. The procedure requires precise BBA of quadrupoles to adjacent BPM beforehand and an orbit feedback in operation. Although these preparation works require some efforts, the method is rather simple and robust. The methodology together with expected performance from analytical estimation and simulations applied to the undulator section of SwissFEL is presented.

THPD19

Technical Overview of SwissFEL Undulator Line

583

R. Ganter, M. Aiba, H.-H. Braun, C. Calvi, A. Fuchs, P. Heimgartner, E. Hohmann, R. Ischebeck, H. Jöhri, B. Keil, N. Milas, M. Negrazus, S. Reiche, S. Sanfilippo, T. Schmidt, S. Sidorov, P. Wiegand
PSI, Villigen PSI, Switzerland

Starting after Linac 3 at z ~ 430 m (z = 0 being the gun photocathode position), the so-called Aramis Hard-X ray undulator section extends over 170 m, from the energy collimator to the electron beam dump. Electrons enter the undulator section with a maximum energy of 5.8 GeV, a slice emittance below 0.43 μm and a peak current of 3 kA with 200 pC of charge. A prototype of the in-vacuum undulator (U15) is currently under assembly. Most of the other beamline components have been designed and for some of them prototypes are already ordered (quadrupoles, beam position monitors, phase shifters, alignment quadrupoles; mechanical supports; safety components). The paper will describe how constraints like temperature drifts, stray magnetic field, wakefields, beam losses, costs are taken into account for the design of components and building (undulators are however described in details in a companion paper).