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PSI Facility News II/2023

Dear Colleagues

Do you know DORA PSI, the institutional repository of PSI? I hope so, as it is certainly a useful source of information about research at PSI and at PSI facilities.

DORA PSI collects all articles authored by PSI researchers. It is fairly complete, since we automatically harvest them from external databases. We are even in the process of retrospectively completing this collection (all journal articles back to 2009 have already been added).

Lothar Nunnenmacher

Additionally, most publications based on research at PSI facilities can be found in DORA PSI as well. However, for this part of the collection no harvesting is possible apart from the Protein Data Bank.

PSI does very well, when it comes to Open Access, and we are proud to see that our four research institutes (Eawag, Empa, PSI and WSL) are at the top of the Swiss Open Access Monitor when it comes to the percentage of Open Access publications.

And now our call to action: If your publication is based on work at a PSI facility and not yet in DORA PSI, please submit it ("Add Publication", no registration required!) and check whether the tag for the relevant facility is there. PSI authors, please also submit the accepted versions of your publications to make them Open Access and more visible, if this is not yet the case. All this can also be done retrospectively!


Lothar Nunnenmacher
Head of Lib4RI, the Library for the Research Institutes within the ETH Domain: Eawag, Empa, PSI & WSL, on behalf of the Lib4RI DORA team

Next proposal submission deadlines

SwissFEL 15 September 2023
SINQ 15 November 2023
SµS 01 December 2023
CHRISP 22 January 2024

A call for SLS proposals will be announced towards the end of the SLS 2.0 upgrade project. An overview of all proposal submission deadlines of the PSI facilities can be found here.

Research highlights

How football-shaped molecules occur in the universe

SLS — Gas-phase synthesis of the C40 nanobowl C₄₀H₁₀

It has long been suspected that fullerenes and their derivatives could form naturally in the Universe. In 2010, the Spitzer infrared space telescope discovered C60 molecules with the characteristic shape of a football, known as buckyballs, in the planetary nebula Tc-1 — the largest molecules ever found in the Universe beyond our solar system. However, how these molecules form has remained unclear. An international team of researchers working at the vacuum ultraviolet (VUV) beamline of SLS has now taken important steps towards understanding how this reaction works. By combining molecular beam experiments with electronic-structure calculations, they have unravelled viable pathways for the gas-phase synthesis of the C40 nanobowl (C40H10). Such nanobowls are fundamental molecular building blocks of fullerenes and of end-capped nanotubes. The study therefore provides insight into potentially common mechanisms in the formation and growth of buckyballs and carbon nanotubes, both in the laboratory and around carbon-rich stars.

L. B. Tuli et al., Nature Communications 14, 1527 (2023)
DOI: 10.1038/s41467-023-37058-y

More information

Make the most of your beam time

SINQ — Active-learning-assisted neutron spectroscopy with log-Gaussian processes

Beam time is precious. This is particularly true for time at neutron three-axis spectrometers such as the EIGER instrument at SINQ. In addition to the high demand and limited availability of these spectrometers, the information density of the measured spectra tends to vary greatly across the four-dimensional Q–E space of a material, in which the momentum space Q is measured sequentially for different energy transfers E. In practice, this means that experimenters often have to spend valuable time searching for signal. Help comes now from a team led by researchers from the Jülich Centre for Neutron Science. Together with the EIGER staff, they have developed and tested a probabilistic active-learning approach that runs autonomously and can identify locations in Q–E space that contain information about the material under investigation, not just background. This increases efficiency significantly — and helps experimentalists to make the best use of their beam time.

M. Teixeira Parente et al., Nature Communications 14, 2246 (2023)
DOI: 10.1038/s41467-023-37418-8

More information

Muonic X-rays peer into brooch from Roman city

SμS and CHRISP — Non-destructive investigation of a late antique knob-bow fibula

The elemental composition of ancient artefacts can tell a wealth of information about past civilisations. Yet archaeologists frequently face an excruciating choice of whether to reveal this information and destroy the artefact, or preserve the artefact for future generations to see, leaving its stories untold. The muon-induced X-ray emission (MIXE) technique, under development at SµS, offers a rare opportunity to analyse the chemical composition deep within an object while leaving it intact. A recent  showcase is the study of a knob-bow fibula, excavated in 2018 in the Roman city of Augusta Raurica in northern Switzerland, in which the elemental makeup was measured at a depth of 0.3–0.4 mm inside the material. The MIXE results show that the fibula was manufactured as two distinct ‘workpieces’, with the compositions suggesting that one — with a higher lead content — was made from cast bronze and the other from forged bronze.

S. Biswas et al., Heritage Science 11, 43 (2023)
DOI: 10.1186/s40494-023-00880-0

More information

First-sight insight

SwissFEL — Ultrafast structural changes direct the first molecular events of vision

The very first step in our perception of light and our ability to see involves only a microscopic change in the protein rhodopsin in our retina, which takes place in less than a picosecond. It is also the only light-dependent step, as the process converts light into electrical signals. PSI researchers have now established exactly what happens in these first molecular events of vision. Working at the Alvra end station of SwissFEL and at the SACLA facility in Japan, the team performed ultrafast time-resolved crystallography at room temperature to determine how the photon energy required to initiate the protein conformational changes is stored. The time-resolved serial femtosecond crystallography allowed them to follow the early structural changes within the protein — one of the fastest natural processes —  and thus to directly visualize, for the first time, the retinal isomerization in a mammalian rhodopsin.

T. Gruhl et al., Nature 615, 939 (2023)
DOI: 10.1038/s41586-023-05863-6

More information

From CERN to PSI with OpenLoops

CHRISP — Low-energy scattering at next-to-next-to-leading order

Precise theoretical predictions of scattering processes are required to explore both the energy and the precision frontier in particle physics. The Particle Physics Theory group at PSI works on both frontiers, taking advantage of the opportunities for synergy. The group of Max Zoller is leading the development of OpenLoops, a tool for efficient and stable numerical evaluation of one-loop amplitudes. This tool has recently been combined with the Monte Carlo code McMule, also developed at PSI, to obtain the first complete results for low-energy scattering processes at next-to-next-to leading order, such as Møller scattering and muon–electron scattering. Further applications related to the MUSE experiment at PSI are ongoing. So far, the two-loop amplitudes have to be taken from external collaborators. In September, Max Zoller will start his SNSF Starting Grant in a joint effort between the University of Zurich and PSI to extend OpenLoops towards two-loop amplitudes.

A. Broggio et al., Journal of High Energy Physics 2023, 112 (2023)
DOI: 10.1007/JHEP01(2023)112

News from the user facilities

SLS: First light in the X06DA-PXIII optics hutch

The Macromolecular Crystallography (MX) beamline X06DA-PXIII was selected as a ‘Phase 0 beamline’ to be upgraded prior to the SLS 2.0 machine upgrade. On 7 June 2023, the PXIII project team — a collaboration of more than 50 people from various expert groups — achieved a milestone: they successfully shone the first light into the optics hutch at the upgraded X06DA-PXIII beamline. This is an essential first step for testing new hardware and software solutions that will be implemented at SLS 2.0. The team is now working to complete the beamline upgrade, with the goal of running user experiments in September, before the start of the SLS dark period.

Read more

SINQ: Ongoing upgrade of AMOR and recent proposal round

The neutron reflectometer AMOR has undergone major refurbishment, with the replacement of the curved guide by full-scale Selene neutron optics, new motors and motion-control devices, and the installation of a MultiBlade detector, developed at the ESS. Currently the software is being adapted at various levels, from device drivers and instrument control to data handling and reduction. We aim to start hot commissioning this summer, so that first user experiments can be performed in the second proposal cycle 2023.

Speaking about the cycle II-23: Again, the demand for SINQ beamtime was extraordinarily large. In total, 306 proposals were submitted by the middle of May, asking for more than 1300 beam days. In particular the small angle scattering facility SANS-I is heavily booked, with 48 new proposals. The review panels gathered between June 27—29 such that the results can be expected by mid-July.

SμS: GIANT progress for MIXE experiments and again great demand for beamtime

The muon-induced X-ray emission (MIXE) technique for the non-destructive study of elemental compositions has experienced a rebirth in recent years. SμS with its high-rate continuous muon beam offers unique capabilities for such experiments. A key role is played by a new dedicated MIXE spectrometer, the Germanium Array for Non-destructive Testing (GIANT) setup. It was built at PSI and has been successfully used in several MIXE campaigns (see the Research Highlight “Muonic X-rays peer into brooch from Roman city” above), acquiring up to 500 spectra per year with some three weeks of beam time. A recent publication now describes the decision-making process, the construction and commissioning of the GIANT setup, and discusses the rich user programme it enables.

At the recent proposal deadline for SμS again the great demand for muon beamtime at PSI became obvious: a total of 104 new proposals were submitted, asking for more than 400 days of beamtime. The call was open for the FLAME, GPD, GPS, HAL-9500 and LEM instruments. Most of the proposals were again submitted for GPS (36), followed by those for the new instrument FLAME (32) and for LEM (16). The proposals are presently under evaluation and we aim to publish the results towards late July / early August.

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SwissFEL: Frequency and spatially chirped free-electron-laser pulses

The team of the Aramis beamline at SwissFEL has succeeded in producing hard X-ray free-electron laser (FEL) pulses that are chirped in both photon energy and spatial position. To achieve this, the beamline was operated without any external focusing and with a tilted, energy-chirped electron bunch whose properties are then transferred to the photon beam. In this way, a frequency-dispersed FEL pulse is provided already from the undulator source, thereby avoiding optical elements — which might reduce the spectral intensity as the FEL signal is dispersed — and making the dispersed signal available at all user stations. In a first demonstration, the tailored FEL pulses were used for a single-shot absorption X-ray spectroscopy experiment, but a wide range of further applications are conceivable, including FEL pulse compression and control of the transverse coherence within the pulse.

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CHRISP: Calibration for space science missions

The Proton Irradiation Facility (PIF) is part of the CHRISP facility and is used to test the response of electronic components to proton irradiation. Its proton beam, originating from the medical cyclotron COMET, can be adjusted over a wide range of energies and intensities. The different settings allow the generation of realistic proton spectra encountered in any possible orbit in space. This enables the qualification of new technologies for future space science missions and the assessment of potential radiation hazards, as for the recently launched ESA JUICE spacecraft. This mission carries on board the high-tech instrument RADEM (Radiation Hard Electron Monitor), which was developed at PSI and calibrated at the PIF. During the eight-year-long journey to Jupiter, RADEM will measure the interplanetary radiation environment. On reaching the gas giant and its icy moons, RADEM will study the complex radiation conditions there and their links to the dynamic magnetic environment of Jupiter.

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Copyright © 2023, Paul Scherrer Institut PSI

The PSI Facility Newsletter addresses the users of the PSI large research facilities and appears quarterly in English. Any feedback is highly welcome! More information. 

Contact: PSI User Office, Phone: +41-56-310-4666, Email: