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Physical review accelerators and beams 19(10), 100702(2016). doi:10.1103/PhysRevAccelBeams.19.100702, The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant and test bed for the development and realization of SwissFEL, the x-ray Free-Electron Laser facility under construction at the same institute. The test facility consisted of a laser-driven rf electron gun followed by an S-band booster linac, a magnetic bunch compression chicane and a diagnostic section including a transverse deflecting rf cavity. It delivered electron bunches of up to 200 pC charge and up to 250 MeV beam energy at a repetition rate of 10 Hz. The measurements performed at the test facility not only demonstrated the beam parameters required to drive the first stage of an FEL facility, but also led to significant advances in instrumentation technologies, beam characterization methods and the generation, transport and compression of ultralow-emittance beams. We give a comprehensive overview of the commissioning experience of the principal subsystems and the beam physics measurements performed during the operation of the test facility, including the results of the test of an in-vacuum undulator prototype generating radiation in the vacuum ultraviolet and optical range., Published by American Physical Society, College Park, MD

Conformational analysis of various forms of glucuronic acid dimers as the model structures of oxidized cellulose has been performed using molecular mechanics with a CVFF force field. The effects of ionization of carboxyl groups, ion pairing with explicit consideration of counter-ions (Na + , Mg 2+ ) and the implicit inclusion of a solvent effect via the dielectric constant, e, have been simulated. The non-ionized glucuronic acid dimer shows conformational behaviour similar to that of unoxidized cellobiose. The ionization of COOH groups leads to strong destabilization of C and D conformers (with both COO - groups on the same side of the molecule), while complexation with counter-ions leads to strong stabilization of these forms which yield highly wound low-pitch helices. An increase in the solvent polarity has an attenuating effect on the behaviour described above.

The Gas Phase Photoemission beamline at Elettra has been commissioned with outstanding success. All photoabsorption spectra taken between 90 and 900 eV have shown resolution which is equal to or higher than any published spectra. The monochromator is a variable angle spherical grating instrument (plane mirror and grating between entrance and exit slits), with an undulator as the source. Some of the problems encountered in commissioning and their solutions are discussed. In particular the calibration is complicated by the fact that an infinite number of angle pairs of the mirror and grating exist for a particular photon energy, whereas only one angle pair gives the highest resolution. A second problem is that the resolution is so high that above about 80 eV, it is much smaller than the lifetime broadening of any known absorption resonance, making any determination of resolution difficult. The experimental chambers available for users are described together with some examples of spectra which have been taken.