No. III/12 - 28 September 2012
PSI photon, neutron and muon user facilities newsletter
PSI's particle accelerators HIPA, SLS and the medical facility PROSCAN represent the backbones of the respective research facilities. The accelerators are operated by a common team from a single control room, nonetheless each has a rather individual character. The high intensity proton accelerator (HIPA) is optimized for beam power to maximize the production of secondary particles, muons and neutrons. Due to several improvements a new record beam power of 1.4 MW was achieved in 2011, after the level of unwanted beam losses was reduced further. The strengths of the Swiss Light Source (SLS) are extremely stable beam conditions and a high brightness, properties that both result in very competitive conditions and unique research opportunities at SLS. Application of advanced optimization techniques to beam orbit and magnet lattice led to a record minimum vertical beam emittance in 2011. PROSCAN has been running since the startup in 2007 without major interruptions of more than a few days for service. This reliability is of utmost importance since the patients must receive their treatment fractions over several weeks without long interruptions.
Operating accelerators at a high level of uptime is always a challenge. These facilities typically contain thousands of active components, and often the failure of a single component is sufficient to interrupt the beam. Individual components must be extremely reliable to ensure predictable operation of the whole complex. Thanks to thoughtful investments by the many involved technical teams, given the limited operation budget, it was possible to establish excellent availabilities at all facilities in recent years. The variety of different technologies and science themes, ranging from challenging cooling problems over ultrahigh vacuum systems to complex beam dynamics makes the operation of particle accelerators an interesting and exciting task. The most satisfying reward for the accelerator team is to observe the intense usage of the facilities by a broad user community with a wide spectrum of research applications.
Mike Seidel, Accelerator Operation and Development, Department GFA, PSI
SLS / SwissFEL - Maintaining the quality of the pulses from an X-ray laser
Ultra-short X-ray laser pulses precisely surveyed for the first timeS. Rutishauser et al, Nature Communications 3, 947 (2012)
X-ray lasers belong to a modern generation of light sources from which scientists in widely different disciplines expect to obtain new knowledge about the structure and function of materials at the atomic level. On the basis of this new knowledge, it could then be possible one day to develop better medicines, more powerful computers or more efficient catalysts for energy transformation. The scientific value of an X-ray laser stands or falls on the quality of the ultra-short X-ray pulses it produces and which researchers use to illuminate their samples. An international team led by scientists from the Paul Scherrer Institute, PSI, has now precisely measured these pulses. In so doing, they have laid the foundation for a scientifically optimal utilisation of X-ray lasers not least, of the planned SwissFEL at PSI. The results of this work have recently been published in the scientific journal Nature Communications.
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SINQ - Innovative results for the car industry
Distribution of soot particles in particulate filters of diesel vehicles seen for the first timeC. Grünzweig et al, MTZ Motortechnische Zeitschrift 73, 326 (2012)
Nowadays, all diesel motor vehicles are fitted with a particulate filter as standard, as part of the 'Euro 5' Emission Standard. These filters prevent the harmful soot and ash particles in exhaust gases from entering the environment. However, within the automotive industry, exactly how the soot particles are deposited inside these filters has not been known. Now, using a special imaging technique - Neutron Tomography - researchers at the Paul Scherrer Institute have made the soot inside filters visible, creating a foundation from which these filters can be optimised and developed further.
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SμS - Nano Science: Tuning the spin dynamics of molecular magnets
Depth-Dependent Spin Dynamics in Thin Films of TbPc2 Nanomagnets Explored by Low-Energy Implanted MuonsA. Hofmann et al, ACS Nano, August 2012
We present measurements of the magnetic properties of thin film TbPc2 single-molecule magnets evaporated on a gold substrate and compare them to those in bulk. Zero-field muon spin relaxation measurements were used to determine the molecular spin fluctuation rate of TbPc2 as a function of temperature. At low temperature, we find that the fluctuations in films are much faster than in bulk and depend strongly on the distance between the molecules and the Au substrate. We measure a molecular spin correlation time that varies between 1.4 μs near the substrate and 6.6 μs far away from it. We attribute this behavior to differences in the packing of the magnetic cores, which change gradually on the scale of 10–20 nm away from the TbPc2 / Au interface.
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ERC Grant for the development of a new imaging method with high potential clinical impactMarco Stampanoni, Assistant Professor for X-ray microscopy at the ETH Zürich and Head of the X-ray Tomography Group of the SLS has been recently awarded one of the coveted European Research Council (ERC) Starting Grant for the project PhaseX: Phase contrast X-ray imaging for medicine. Marco Stampanonis project will be supported by the ERC with 1.5 million euros for the next 5 years. The highly competitive ERC Starting Grants are reserved for outstanding young research talents. With his team, Stampanoni has been working on the development of phase contrast X-ray imaging methods since several years. This technique can potentially revolutionize the radiological approach to medical imaging because it is intrinsically capable of detecting subtle differences in the electron density of soft tissue and of measuring the effective integrated local small-angle scattering power generated by the microscopic density fluctuations in a specimen. It goes therefore well beyond the conventional, absorption-based approach used daily in the clinical routine which usually lacks in contrast when imaging soft-tissue. Stampanonis ERC project aims at transferring this technique -- so far successfully and efficiently implemented exclusively on synchrotron -- to the clinical environment, with the final purpose to provide medical doctors a new, powerful diagnostic tool. A few preliminary applications of the method have been investigated in the field of mammography and Alzheimer research already.
New calls for proposalsSLS: PX-beamlines
deadline: October 15, 2012
SLS: non-PX beamlines
deadline: March 15, 2013
deadline: November 15, 2012
SµS/instruments LEM, GPS, LTF, and GPD
deadline: December 2012
An overview about all proposal submission deadlines of the PSI facilities can be obtained here.
Upcoming eventsStructural Dynamics and Dynamical Structures
October 3-5, 2012, Grenoble, France
LCLS/SSRL Users Meeting
October 3-6, 2012, San Fransisco, USA
JCNS Workshop 2012: Trends and Perspectives in Neutron Scattering for Soft Matter and Biophysics
October 8-11, 2012, Tutzing, Germany
EMBO practical course on Solution Scattering from Biological Macromolecules
October 17-24, 2012, Hamburg, Germany
SwissFEL Pump Laser Workshop
November 16, 2012, Villigen PSI, Switzerland
SwissFEL Sample Mounting and Injection Workshop
November 20, 2012, Villigen PSI, Switzerland
SAS2012: International Small-Angle Scattering Conference
November 18-23, 2012, Sydney, Australia
MRS Symposium VV: Advanced Materials Exploration with Neutrons and Synchrotron X-Rays
November 25-30, 2012, Boston, MA, USA
PSI Powder Diffraction School
November 27-29, 2012, PSI Villigen, Switzerland
5th MaNEP Winter School - Understanding electronic and magnetic correlations
January 13-18, 2013, Saas-Fee, Switzerland
Facility newsSLS: Advanced diffraction data collection with multi-axis goniometer and single-photon counting detector at beamline X06DA
A new type of multi-axis goniometer called PRIGo (Parallel Robotics Inspired Goniometer) has been developed for macromolecular crystallography applications at the Swiss Light Source. It allows to precisely reorient crystals and to collect very accurate data with high mechanical precision. With the very compact design, it offers the highest degree of freedom in a crowded sample environment. Combined with single-photon counting PILATUS 2M-Fast detector, the beamline X06DA now offers new data collection opportunities taking full advantages of crystal geometry and detector properties. This setup is therefore extremely well suited for difficult phasing experiments and allows users to tackle even more challenging projects.
SINQ: EIGER spectrometer in user operation
The new thermal triple-axis spectrometer EIGER is available for user operation in the next SINQ cycle and is ready to receive first proposals. The instrument will therefore be fully included into the next call for proposals, which will end with the submission deadline on November 15.
Interested users are kindly requested to contact the instrument responsible in advance of submitting a proposal to discuss the feasibility of the planned experiments.
SμS: New capabilities for Low Energy Muon experiments
The LEM spectrometer has been extended by the possibility to illuminate the sample with light and simultaneously perform µSR or resistivity measurements. The new setup utilizes LEDs which are able to provide a light intensity of up to 100 mW/cm2 at the sample with a wavelength of 405 nm. It is of special advantage that the probing depth of the low energy muons perfectly matches the attenuation length of the used light. An external stimulus like light now allows to use LEM to study unconventional electronic states of matter in an out-of-equilibrium situation.
SwissFEL: New opportunities for coherently exciting magnetic materials
The ability to manipulate matter on ultra-short time scales offers potential breakthroughs in future device technologies as well as a better understanding of fundamental material properties. For this purpose, it is of immense importance to be able to selectively drive excitations of interest. This has recently been demonstrated by team of researchers from PSI, the ETH Zurich, Stanford (SLAC) and Berkeley with an experiment (performed in July 2012) at the x-ray free electron laser LCLS more information.
Current OpeningsJob opportunities at PSI
PSI Users Association - board electionsOver the summer the PSI users association JUSAP organised the election of part of its board members, whose term of office ended in rotation by August 2012. In particular, Bernd Schönfeld from ETH Zurich stepped back from his duties after four years being chairman of JUSAP between 2008 and 2012. Bernd really was a driving force behind several innovations regarding the representation of the PSI users: During his term of office the association was extended to represent not only the SLS but also the SINQ and SμS users. He was also very active in initiating the JUM@P Joint Users Meetings, which are now regularly organized every two years as well as in calling for a regular electronic feedback from the users regarding their experiments performed recently. Dear Bernd, PSI and its user community thank you very much for your strong engagement over the past years.
The new head of JUSAP has been elected now: Sarah Dunsiger from TU Munich took over the task as chairwoman from September 1, 2012. We wish her all the best for the new task and look very much forward to a continuation of a very good cooperation between PSI and JUSAP.
A list of all board members and contact addresses is available from the JUSAP webpage.
User feedbacksSince 2010 the PSI User Office calls regularly for an electronic feedback from the users. A few weeks after each experiment every participant receives an email with a request to take 5 minutes and fill in a brief online questionnaire with feedback about the recent experiment and stay at PSI.
In 2011 totally 1300 users participated and provided feedback in the various categories. The best rated categories were 'scientific support', 'technical support', 'machine operation', 'beamline hardware' and 'Digital User Office (DUO)'. In those categories far more than 90% of the users gave one of the two highest scores "5" or "4". Main criticism on the other hand are the missing opening hours of the PSI restaurant during the weekends - a problem, which is not easy to solve.
The overall impression of our users is extremely positive: In this category 56% of the users provided the highest score (5), 34% gave a "4", 8% a "3" and only 2% rated their stay with the two lowest scores "1" or "2". Thanks a lot for continuously providing this feedback, which helps us enormously to improve the service for our users!