Dear colleagues,

Last month, we celebrated the 50th anniversary of the ring cyclotron at the HIPA facility. With unmatched performance for a proton cyclotron, it is world-leading in terms of producing high-intensity secondary pion and muon beams for CHRISP and SμS, and it drives two unique neutron sources, SINQ and UCN. With appropriate support and maintenance, HIPA will continue to operate successfully for several more decades.

The project to install a new target station H, replacing the M target, and two new ‘High Intensity Muon Beamlines’ (HIMB) was linked with the ‘Targeted Alpha Tumour Therapy and Other Oncological Solutions’ (TATTOOS) project to form the ‘Isotope and Muon Production using Advanced Cyclotron and Target technologies’ (IMPACT) project. IMPACT was endorsed by Swiss community roadmaps and the ETH Domain and became part of the Swiss Roadmap for Research Infrastructures 2023. 

While awaiting the funding decision by the Swiss parliament, which is expected by December of this year at the latest, the pre-project at PSI is in full swing. Several scientific communities are looking forward to the implementation of IMPACT, which will provide unprecedented muon intensities starting from 2028, and radionuclides from 2030. Indeed, very exciting times ahead!

Klaus Kirch
On behalf of the Laboratory for Particle Physics, Research with Neutrons and Muons - NUM 

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.

In laser additive manufacturing, the 3D printing of metallic objects using powders and lasers, the occurrence of unexpected defects often hamper the printing process. Traditional monitoring methods, such as thermal imaging and machine learning algorithms, often miss or misinterpret defects, making precision manufacturing impossible and therefore hindering the adoption of the technique by key industries such as aerospace and automotive. Working at the TOMCAT beamline of SLS, a Swiss research team has now introduced a groundbreaking approach to defect detection. They used operando synchrotron X-ray imaging synchronised with acoustic emission recording to monitor changes that occur under constant laser processing — essentially picking up on the fly differences in the sound the printer makes during a flawless print and one with irregularities. This provides a robust new method for accurately detecting undesirable processing regimes by identifying the correlation between individual physical events and their acoustic signatures.

M. Hamidi Nasab et al., Nature Communications 14, 8008 (2024)
DOI: 10.1038/s41467-023-43371-3

Magnetic skyrmions, with their distinctive vortex-like magnetic spin configurations, continue to intrigue researchers due to their potential applications in nanoscience and technology. Traditionally, skyrmions form two-dimensional hexagonal close-packed lattices, with the skyrmions themselves displaying one of just two types of internal magnetization texture, known as Bloch- or Néel-type. Recent theories hinted at the prospect of reconfigurable transitions between skyrmion phases of different lattice types and internal textures. Until now, experimental evidence to support such theories has been scarce. New research at SINQ reveals that the polar tetragonal magnet EuNiGe₃ hosts two so-called hybrid skyrmion phases, each exhibiting unique internal textures characterized by different combinations of Bloch- and Néel-type windings. A particular novelty of the results is the direct transition between the two phases, triggered by varying a magnetic field, which coincides with a hexagonal-to-square skyrmion lattice transformation. 

D. Singh et al., Nature Communication 14, 8050 (2023)
DOI: 10.1038/s41467-023-43814-x

In multiband superconductors, where two or more bands contribute to the electron pairing, the coexistence of flat and dispersive bands can give rise to intriguing scenarios, including a strong increase in the transition temperature, which might potentially explain the phenomena of high-temperature superconductivity. A team led by PSI researchers has now studied the role of band flattening in the superconducting mechanism of the recently discovered superconductor family Mo₅Si_3−xP_x. Combining measurements of the magnetic penetration depth, the upper critical field, and the specific heat with first-principles calculations, they find that a flat region in the band structure of this bulk system gradually approaches the Fermi level as a function of the phosphorus doping x. On reaching the Fermi level at x ≃ 1.3, an abrupt change occurs in almost all superconducting quantities. These results suggest that the emergence of a flat band right at the Fermi level enhances correlations between conducting electrons, and that the superconducting properties of Mo₅Si_3−xP_x might be controlled by external parameters such as strain and pressure.

R. Khasanov et al., Nature Communications 15, 2197 (2024)
DOI: 10.1038/s41467-024-46514-2

Damage to the genetic material DNA drives cancer, ageing, and cell death. DNA repair is therefore crucial for all organisms, and a deeper understanding of this fundamental function helps us to better grasp how life around us survives and thrives. An international team of researchers has now revealed how the enzyme photolyase efficiently channels the energy of sunlight into DNA-repair chemistry. Using time-resolved crystallography at the Alvra beamline of SwissFEL, the scientists were able to capture the excited state of the photolyase chromophore and to understand exactly how the enzyme uses light so efficiently. They determined ten time-resolved structures of photolyase in the act of DNA repair, illuminating in unprecedented detail the function of this system. These results are significant as photolyase plays an important role in DNA repair in almost all species — unfortunately, however, humans lack this enzyme and must rely on other DNA repair mechanisms.

N.-E. Christou et al., Science 382, 1015 (2023)
DOI: 10.1126/science.adj4270

M. Maestre-Reyna et al., Science 382, eadd7795 (2023)
DOI: 10.1126/science.add7795

High-precision physics searches for an electric dipole moment of the neutron (nEDM) require incredibly stable and uniform magnetic-field environments. The n2EDM experiment at CHRISP hosts a large magnetically shielded room and an active magnetic-shielding system, both of which enable extremely low and uniform magnetic fields to be achieved inside the room, where the physics measurement takes place. More specifically, the six-layer magnetically shielded room is equipped with a series of current-carrying coils wrapped around each layer to demagnetize the room. Recently, n2EDM researchers demonstrated the ability to reach magnetic fields below 300 pT (five orders of magnitude smaller than the Earth magnetic field) in the central cubic-metre volume, significantly better than what was previously possible. Based on this achievement, the n2EDM experiment can claim to host the world’s best magnetic environment for ongoing nEDM measurements.

N. J. Ayres et al, European Physical Journal C 84, 18 (2024)
DOI: 10.1140/epjc/s10052-023-12351-8

The HIPA facility turns 50

The High Intensity Proton Accelerator Facility (HIPA), which provides a 1.4-MW proton beam for the production of mesons and neutrons at PSI, turns 50 this year. On 27 February, guests from near and far came to PSI to celebrate this special anniversary, including many scientists, engineers, and technicians who work or have worked at HIPA.

The programme offered a look back on HIPA’s rich history, a celebration of the outstanding science it has made possible, as well as a glimpse into the future. Conceived in the early 1960s as a Swiss “meson factory”, it was commissioned in 1974, reached its original target of 0.1 milliamperes beam current by the end of 1976, and over the years saw the founding of PSI in 1988, and the commissioning of SINQ in 1996 and of the UCN source in 2011, and reached an increase of the beam current by a factor of more than 20.

And the evolution of HIPA is far from over. The IMPACT project continues, on the one hand, the history of the meson factory, by replacing one of the two graphite targets to increase the number of muons available per second by a factor of 100. On the other hand, IMPACT is to establish a completely new facility at HIPA, for the production of radionuclides for targeted cancer diagnostics and therapy. (For more information, see also the Editorial.)  

CHRISP Users Meeting BV55

The 2024 edition of the Users Meeting for the CHRISP facility — the 55^th such meeting — took place from 5 to 7 February 2024. As in previous years, the first day was dedicated to closed half-day, in-depth status reviews of the MEG II, Mu3e, n2EDM, and MUSE experiments. On the second day, the Open CHRSIP Users Meeting BV55 took place. The PSI Director welcomed the participants and gave a short presentation on new developments and highlights from PSI. In the first part of the following session, new proposals were presented, including a new lifetime measurement of the free neutron at the UCN source and measurements of muonic atoms. Stimulating discussions continued during the progress talks of the projects on measurements of the muon electric dipole moment, pion decays, muon-catalysed fusion, free fall of muonium, and muon beam compression. The meeting concluded on the third day with the oral feedback and recommendations to the projects by the Chair of the Research Committee for Particle Physics at the Ring Cyclotron and the presentation of the beam time assignment. 

SLS: A heated rock-deformation apparatus for the 4D visualization of sample evolution

X-ray micro-computed tomography (µCT) offers unique insights into the 3D microstructure of a wide range of samples. Combined with confinement in a pressure vessel, the technique is particularly useful for studying grain-scale transformations of geological materials. Now a new portable rig has been introduced and tested in a series of experiments at the TOMCAT (SLS), I12 JEEP (Diamond Light Source) and PSICHÉ (Synchrotron SOLEIL) beamlines. The new Heitt Mjölnir rig can generate triaxial stress and temperature conditions similar to those found in Earth’s upper crust, while allowing time-resolved microtomography. It thereby pushes the boundaries of experimental capability, in particular for the study of fluid–rock interactions.

SINQ: FALCON double-detector Laue diffractometer add-on for grain mapping at POLDI

In early 2020, an agreement was made between the Helmholtz-Zentrum Berlin (HZB) and PSI to transfer the Laue Diffractometer Falcon (E11) from HZB to PSI, making this state-of-the-art instrument from the recently decommissioned BER-II research reactor available to the scientific community at SINQ. Falcon arrived at PSI in July 2020, and since then a modern and versatile instrument has been built and commissioned at SINQ. A recent publication now describes the functionality of the new FALCON system in conjunction with 3D Laue neutron diffraction tomography at the POLDI beamline of SINQ, demonstrating its potential for improved morphology reconstructions and strain mapping, among other applications.

SμS: Introduction to Muon Spin Spectroscopy

PSI researchers Alex Amato and Elvezio Morenzoni have published a new textbook entitled 'Introduction to Muon Spin Spectroscopy: Applications to Solid State and Material Sciences'. It serves as a comprehensive introduction to muon spin spectroscopy (µSR), focusing on key applications including the study of magnetism, superconductivity and semiconducting materials in both bulk and thin-film samples. In addition, two chapters delve into the applications of negative muons, emphasizing their role in elemental materials analysis and introducing fundamental particle-physics aspects of muon science.

SwissFEL: Millijoule femtosecond X-ray pulses by fresh-slice multi-stage amplification

Standard X-ray FEL pulses have durations of tens of femtoseconds — which can be too long for many applications because of the risk of electronic damage. One of the methods to achieve intense shorter pulses is multi-stage fresh-slice amplification. A team at the Athos soft X-ray beamline of SwissFEL now reports the generation of X-ray pulses with millijoule energies and femtosecond durations using this approach. Their implementation is both efficient and robust: It essentially uses the entire electron bunch in the FEL process and requires merely 32 metres of undulators, taking full advantage of the high flexibility of the Athos design.

CHRISP: New proton-beam monitors for the ultracold neutron source

The ultracold neutron (UCN) source is the second spallation target station at PSI. During standard operation, the full proton beam — up to 2.4 mA — is directed every 300 seconds towards the target for a length of up to eight seconds. Precise guiding of the proton beam is therefore a must, not only to achieve maximum neutron production, but most importantly to ensure operational safety. Two harp monitors provide information on the position of the proton beam in the final beamline towards the UCN spallation target, giving fast feedback for any necessary beam steering. When the second harp detector malfunctioned in November 2023, UCN operation had to be stopped. One replacement detector was already prepared and available, and rapid intervention by the beam controls group during a three-day service period allowed UCN operation to continue until shutdown. During the 2024 shutdown period, the first harp monitor was also replaced. Both are now again fully functional and provide the necessary beam-position information for safe operation of the UCN source in 2024.

Dear colleagues,

Are you a researcher working on materials development for the circular economy? The ReMade@ARI project (REcyclable MAterials DEvelopment at Analytical Research Infrastructures) has tailored services available for you. 

The unique ReMade@ARI services include easy and coordinated access to more than 50 European advanced analytical research infrastructures, user support, and much more. 

Exploring the properties and structures of recyclable materials is made possible by using an impressive range of analytical techniques.  

Take advantage of the ReMade@ARI services and submit proposals for access to these infrastructures. The ReMade@ARI project has currently two open calls for proposals — ReMade-TNA and ReMade-SME — dedicated to scientists in academia and in small and medium enterprises (SMEs), respectively. Please note the quickly approaching submission deadline for ReMade-TNA proposals of 10 April 2024. Your proposals are highly welcome. 

Moreover, the kick-off meeting of the NEPHEWS project (NEutrons and PHotons Elevating Worldwide Science) took place at the SOLARIS national synchrotron centre in Krakow, Poland, on 8—9 February 2024. Within NEPHEWS, 21 synchrotrons, free-electron lasers, and neutron research infrastructures are working together with the European Neutron Scattering Association (ENSA) and the European Synchrotron and Free Electron Laser User Organisation (ESUO), for example to support scientists, especially from European developing countries, Ukraine and Africa, to get access to the photon and neutron project facilities and to promote research excellence. 

We encourage all members of the PSI user community to contact us regarding any issues that concern user operation at PSI.

Yours sincerely,

Joanna Hoszowska and Annick Froideval
On behalf of the JUSAP committee

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