The Polish Free Electron Laser, PolFEL was proposed more than decade ago and at that time was accepted for the Polish Roadmap for Research Infrastructures. The facility was proposed to be built in two stages, at first, with fewer accelerating sections and lower beam energy and the second one, with more accelerating sections, delivering 600 MeV electrons to VUV undulator, generating in the Self Amplified Spontaneous Emission process coherent radiation at wavelength ranged down to 27 nm and 9 nm in the first and third harmonic mode, respectively. Over past decade new experimental methods have been proposed and developed, delivering interesting results obtained with relatively low energy coherent and non-coherent photon beams, for example with IR-UV and THz radiation. In this contribution, subsystems of an updated version of the first stage PolFEL facility will be discussed. The project has recently received funds from the Smart Growth Operational Programme, Measure 4.2: Development of modern research infrastructure of the science sector, and is currently in a preparation phase of the construction, which will begin in 2019.
Solaris synchrotron storage ring which has been assembled at the beginning of the 2015, consist of twelve integrated magnets blocks performing the part of double bend achromat. Both magnets as well as the whole ring as concept is a replica of Max IV 1.5 GeV ring and utilize pioneering integrated magnets approach. Solaris ring assembly forewent that of its Swedish twin. It is a successful proof of principle experiment showing the feasibility of the chosen approach. On the other hand it was an exercise which brought the knowledge on mechanical behavior of the magnets blocks and matching components, which is of unique importance for further integrated magnets implementations. Hereby we present selected issues related to the ring assembly: block stiffness verification and straightness rectification, vacuum chamber installation, alignment and mechanical stability of the assembled system.
Jerzy Lorkiewicz, Robert Nietubyc, Jacek Sekutowicz, Marek Barlak, Denis Kostin, Anna Kosinska, Roman Barday, Rong Xiang, Robert Mirowski, Wojciech Grabowski, Jan Witkowski
Results are reported on using evaporation and UHV arc lead deposition to create thin-layer superconducting Pb photocathodes on niobium wall of electron gun. Evaporated photocathodes were prepared and tested for the first time in 2014. A complete XFEL-type photo-injector with an evaporated photocathode underwent successful quality check at DESY - an acceptable working point was reached. On the other hand poor adhesion to niobium proved to be the most serious shortcoming of the evaporated Pb layers. UHV arc deposition seems to be much more promising in this context as it allows energetic coating. Filtered arc coating lead to creation of uniform, 2 μm thick lead layers with casual spherical extrusions which enhance locally electric field and leads to high dark current. Conditioning in electric field is needed to reduce the field emission effects from these layers to acceptably low value. Using non-filtered UHV lead deposition enabled fast coating up to a thickness above 10 μm. Pb films obtained in this way require further post-processing in pulsed plasma ion beams in a rod plasma injector. In order to reach a sufficiently planar film surface the pulsed heat flow through a lead layer on niobium was modeled and computed.
The short range order around Pd atoms in nanometer-size grains embedded in carbonaceous films deposited with two-step
process: physical vapor deposition (PVD) followed by chemical vapour deposition (CVD) was studied. The Pd K-edge
X-ray Absorption Fine Structure Spectroscopy was applied. We have found that grains obtained in a sole PVD process
contained metallic fcc palladium or amorphous palladium oxide dependently on Pd concentration and duration time of
process. In the oxide fraction a short range order around Pd atoms was strongly reduced as compared to a reference PdO
powder. Subsequent CVD resulted in pure Pd fcc crystallites. The accompanying annealing was found to predominantly
determine the content and structure of formed Pd grains.
We report the efforts undertaken at NCBJ and some of its collaborating laboratories dedicated to prepare pure and flat lead film coated onto niobium to operate as superconducting photocathodes. Three approaches to lead cathodic arc deposition have been implemented and tested: active plasma flux filtering, passive filtering and unfiltered flux. None of them allowed us to find a proper balance between thickness and surface roughness of a cathode. At that point efforts were taken to establish post-deposition heat treatment of lead film.
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