Scientific Highlights
Coexistence of Physisorbed and Solvated HCl at Warm Ice Surfaces
The interfacial ionization of strong acids is an essential factor of multiphase and heterogeneous chemistry in environmental science, cryospheric science, catalysis research and material science. Using Near Ambient Pressure X-ray Photoelectron (NAPP) spectroscopy, we directly detected a low surface coverage of adsorbed HCl at 253 K in both molecular and dissociated states and interpret the results as physisorbed molecular HCl at the outermost ice surface and dissociation occurring upon solvation deeper in the interfacial region. This study gives clear evidence for nonuniformity across the air−ice interface and questions the use of acid−base concepts in interfacial processes.
Commissioning and first performance studies of the new CMS pixel detector
In the previous months the new CMS pixel detector was brought into operation. The detector was moved from PSI to CERN and installed in February, followed by an intensive period of commissioning and calibration. This process mostly involved the adjustment of many operational parameters which influence the detector performance, e.g.
ATHOS Conceptual Design Report (CDR)
The ATHOS Conceptual Design Report has recently been completed and describes the ATHOS project in detail. The CDR starts with a summary of the characteristics of the ATHOS undulator line. Especially the design parameters of the different ATHOS operation modes are explained and illustrated by simulation results. The core part of the report is a description of all key components, i.e. from the electron bunch extraction kicker down to the ATHOS experimental stations.Download the full report Athos CDR .
ATHOS Conceptual Design Report (CDR)
The ATHOS Conceptual Design Report has recently been completed and describes the ATHOS project in detail. The CDR starts with a summary of the characteristics of the ATHOS undulator line. Especially the design parameters of the different ATHOS operation modes are explained and illustrated by simulation results. The core part of the report is a description of all key components, i.e. from the electron bunch extraction kicker down to the ATHOS experimental stations.
Sorption of trivalent lanthanides and actinides onto montmorillonite
The credibility of long-term safety assessments of radioactive waste repositories may be greatly enhanced by a molecular level understanding of the sorption processes onto individual minerals present in the near- and far-fields. A study conducted at LES in collaboration with the Helmholtz Zentrum Dresden Rossendorf used extended X-ray absorption fine structure (EXAFS) and time-resolved laser fluorescence spectroscopies (TRLFS) to elucidate the uptake mechanism of trivalent lanthanides and actinides (Ln/AnIII) by the clay mineral montmorillonite.The excellent agreement between the thermodynamic model parameters obtained by fitting the macroscopic data, and the spectroscopically identified mechanisms, demonstrates the mature state of the 2SPNE SC/CE sorption model developed at LES for predicting and quantifying the retention of Ln/AnIII elements by montmorillonite-rich clay rocks.
Composite laminated cruciform design for multiaxial testing of metals
Multiaxial mechanical testing of sheet metals is far from trivial, which is mainly related to issues with sample design and fabrication. PSI scientists have developed a new methodology to produce cruciform shaped samples from thin sheet metals based on a novel bottom-up approach. A proof-of-principle experiment based on polymer lamination of an aluminum thin sheet demonstrates the effectiveness of this new approach.
Dr. Nan Xu awarded SPS 2017 Prize in Condensed Matter Physics
The SPS 2017 Prize in Condensed Matter Physics, sponsored by IBM, has been awarded to Dr. Nan Xu for his excellent work on topological quantum states. Dr. Nan Xu is a joint postdoc of Paul Scherrer Institute (PSI) and the École Polytechnique Fédérale de Lausanne (EPFL).
First beam in optics hutch
On August 31st, 2017, SwissFEL reached the next milestone by sending the first X-rays into the Optics Hutch. The Aramis undulators of SwissFEL produced SASE-radiation with 1.2 nm wavelength. The beam entered the Aramis-beamline along the pink beam path of Bernina via two vertical offset mirrors and was detected on the diagnostic photon screen at the end of the Optics Hutch. A stable and well shaped beam with a diameter of 1.5 mm was observed. With the bendable offset mirrors we were able to manipulate the profile to enlarge and reduce the vertical its size from 660 µm (rms) down to 260 µm (rms) without introducing distortions. The gas based intensity and position monitor in the frontend could be calibrated and determined a pulse energy of approximately 5 µJ. We are now looking forward to the next commissioning time in October to commission the monochromatic beam path of Bernina and the second branchline Alvra.
First beam in optics hutch
On August 31st, 2017, SwissFEL reached the next milestone by sending the first X-rays into the Optics Hutch. The Aramis undulators of SwissFEL produced SASE-radiation with 1.2 nm wavelength.
Swiss Neutron Scattering Prize
Viviane Lutz-Bueno was awarded the Swiss Neutron Scattering Prize of the Swiss Neutron Scattering Society, at the Joint Annual Meeting of the Swiss and Austrian Physical Society, for her PhD thesis Effects of formulation and flow on the structure of micellar aggregates carried out at ETH Zürich. Viviane is currently a postdoctoral fellow at the CXS group at PSI, developing scanning SAXS analysis methods.