Insertion devices (ID)
We design, build and run undulators for SLS/SLS-2 and SwissFEL and support the beamlines
The SLS was the first medium energy 3rd generation synchrotron light source which covered both soft and hard x-ray beamlines in one machine. For the hard x-ray short-period, small gap in-vacuum undulators with 19mm periods and minimum gaps of 4mm are operated at high harmonics up to photon energies of 20keV. The only wiggler which was installed in 2001 could be replaced in 2010 by a cryogenic in-vacuum undulator with only 14mm period to achieve even higher photon energies up to 35keV. For the soft x-ray beamlines all undulators provide variable polarization with different types of APPLE II undulators with variable and fixed gaps, and, to reach lowest photon energies of 10eV, one quasi-periodic electromagnetic undulator.
For the first SwissFEL beamline named ARAMIS, an undulator with about 60m total length has been designed, built and is currently under comissioning. The in-vacuum undulator consists of 13 modules of 4m length each. With a periodlength of 15mm there are 265 periods per module, in total 3500 periods. The gap range in operation varies only between 3mm and 6mm which gives a tuning range from K = 1.8 to 1.0. The gap change is realized with a most direct wedge-based system which allows sub-μm precision. The wedges transport the stiffness of the closed support structure out of cast mineral to the beam axis. A keeper design based on flexors allows precise and for the first time an automated correction of the remaining field errors.
The second SwissFEL beamline named Athos is for soft x-rays which requires light with variable polarization. A new concept for APPLE undulators, the APPLE-X, has been developed which allows now full control of fields and gradients in a full symmetric way. For highest flexibility all 16 undulator modules with 2m length and 38mm period will be of this APPLE-X type. This new concept allows several modes of operation which will make the ATHOS line worldwide unique.
The planned upgrade to SLS will affect mainly the hard x-ray undulators and the electromagnetic undulator. The better electron beam quality will be best matched with shorter period undulators which can be achieved by converting the existing U19 in-vacuum undulators to cryogenic ones. The electromagnet has to be replaced by a shorter twin APPLE-X type undulator system.
The ID team worked successful in a team with experts from SYN, AMI and GFA and in close collaboration with our main industrial partner DAETWYLER AG, which started already in the design phase.
Scientific Highlights and News
L'Institut Paul Scherrer (PSI) et la société Max Daetwyler AG (Bleienbach) (MDC) viennent de signer ce jour un contrat de coopération pour le développement et la fabrication de composants essentiels, destinés au laser à rayons X du SwissFEL, le nouveau grand instrument de recherche du PSI.