2021 Impact factor 3.131
Hadrons and Nuclei

EPJ D Colloquium - Overview of photo-neutralization techniques for negative ion-based neutral beam injectors in future fusion reactors

The need for safe, carbon-free and abundant sources of energy is becoming more and more pressing. While still under development, nuclear fusion can play a key role in a medium term, decarbonized energy scenario. However, in order for fusion to be commercially competitive, many sub-systems constituting the current experimental reactors need to be optimized in terms of their efficiency: in particular, DEMO and future fusion energy plants will require a substantial increase in the energy performances of the plasma heating systems.

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EPJ D Highlight - Investigating the temperature of large biomolecules in ion-storage rings with jellyfish protein

To study temperature in ion-storage rings, researchers used a model of a biomolecule found in the jellyfish Aequorea victoria. Credit: Sierra Blakely [https://en.wikipedia.org/wiki/ File:Aequorea4.jpg]

New research introduces a simple way to determine the temperature of a stored biomolecule and assess how it changes over time

The range of applications for ultracold molecular systems has grown impressively over recent years to include interstellar chemistry, spectroscopy, and arguably most excitingly, quantum computing.

One way of cooling molecules is by trapping them in cooled ion traps to which the molecules are thermalised before being injected or by injecting them into a room temperature storage ring and then cooling it. To do this effectively, researchers need a method to determine the temperature of molecular ions in an ion-storage ring.

New research published in EPJ D introduces a relatively simple new way to determine the temperature of stored biomolecular ions produced by electrospray ionization, and measure the time evolution of the temperature. The research is authored by Anne P. Rasmussen, Ricky Teiwes, and Lars H. Andersen of the Department of Physics and Astronomy, Aarhus University, Denmark, along with Dilara A. Farkhutdinova, and Anastasia V. Bochenkova of Lomonosov of the Moscow State University chemistry department, Russia.

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EPJ D Highlight - Investigating positron scattering from giant molecular targets

Positron scattering from a carbon 60 molecule. Positrons can be an important probe of the quantum properties of larger molecules. Credit: Robert Lea.

New research looks at positron scattering from rare gas atoms encapsulated in carbon 60 to investigate quantum properties that can’t be tested with electrons.

Particle scattering is an important test of the quantum properties of atoms and larger molecules. While electrons have historically dominated these experiments, their positively charged antimatter counterparts — positrons — can be used in promising applications when the negatively charged particles aren’t suitable.

A new paper published in EPJ D examines the scattering of positrons from rare gas atoms stuffed inside the fullerenes — so-called “rare gas endohedrals.” The paper is authored by Km Akanksha Dubey from the Indian Institute of Technology Patna, Patna, Bihta, India, and Marcelo Ciappina, Guangdong Technion-Israel Institute of Technology, Shantou, China.

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EPJ D Highlight - Optimizing silicon structure to reduce reflection

An electron microscope observation of porous silicon samples. A new paper examines the effect of porous structure on light trapping.

New research connects the porous structure of silicon and its ability to “trap” incident light.

The world sits on the brink of a major ecological disaster and the need for renewable energy sources has never been more urgent. Perhaps the most significant source of untapped renewable energy is, unsurprisingly, the Sun. It is little wonder that much of the focus of renewable energy research focuses on solar power.

A new paper published in EPJ D examines changes in the porous structure of silicon to make it less reflective and thus a better material for solar absorbing technology. The paper is authored by Daohan Ge, Zhou Hu, Zhiwei Fang, Chao Ni, and Liqiang Zhang of the Institute of Intelligent Flexible Mechatronics, Jiangsu University, China, and Shining Zhu of the National Laboratory of Solid State Microstructures, Nanjing University, China.

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EPJ D Highlight - Astrophysical plasma study benefits from new soft X-ray transition energies benchmark

An artist’s impression of an X-ray binary, the kind of cosmic event that will benefit from a new benchmark in the study of astrophysical plasmas. Credit: Dana Berry/NASA Goddard Space Flight Center

The new benchmark for X-ray transition energies set for neon, carbon dioxide, and sulfur hexafluoride paves a pathway to high accuracy analysis of astrophysical plasmas.

The analysis of astrophysical plasmas is vital in the quest to learn about some of the Universe’s most powerful and mysterious objects and events such as stellar coronae and winds, cataclysmic variables, X-ray binaries containing neutron stars and black holes, supernova remnants, or outflows in active galactic nuclei. The success of such research will lead to future astrophysical X-ray observatories enabling scientists to access techniques that are currently not available to X-ray astronomy. A key requirement for the accurate interpretation of high-resolution X-ray spectra is accurate knowledge of transition energies.

A new paper published in EPJ D authored by J. Stierhof, of the Dr. Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics of Friedrich-Alexander-Universt Erlangen-Nürnberg, Bamberg, Germany, and coauthors utilizes a newly introduced experimental setup at the BESSY II synchrotron facility to provide precise calibration references in the soft X-ray regime of neon, carbon dioxide, and sulfur hexafluoride gases.

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EPJ D Highlight - Assessing and optimising the quality of sensor networks

The GNOME network

A new method for optimising the arrangements of complex sensor networks could lead to improvements in a variety of cutting-edge experiments: including the ongoing search for Dark Matter

Rather than using a single, centralised sensor to gather data, many experiments deploy multiple sensors in complex networks. This offers numerous advantages: including higher sensitivities and resolutions in experimental measurements, and the ability to catch and correct errors more effectively. Yet with all the complexities involved in managing each sensor, and collecting all of their data streams at once, it can be extremely challenging to determine how the sensors should be arranged to obtain optimal results. Through new research published in EPJ D, Joseph Smiga at Johannes Gutenberg University Mainz proposes a new way to quantify the quality of sensor networks, and uses his methods to suggest improvements to existing experiments.

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EPJ D Highlight - Quantum battles in attoscience: Following three debates

Quantum battles in attoscience: tunnelling

Discussions among an extensive panel of attoscience researchers have clarified points of tension within the field, and offer new suggestions of how research should move forward in the face of these divisions.

In July 2020, 300 researchers from 34 different countries attended the CECAM virtual workshop, ‘Quantum Battles in Attoscience’. EPJ D presents three community papers which emerged from the in-depth panel discussions held at this occasion.

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EPJ D Highlight - Understanding the ionisation of proton-impacted helium

Calculating electron emission angles

Advanced mathematical analysis of the ionisation of a helium atom by an impacting proton has revealed where discrepancies arise between experiments and existing theoretical calculations of the process

When an atom is impacted by a fast-moving proton, one of its orbiting electrons may be knocked away, leaving behind a positively-charged ion. To understand this process, it is important for researchers to investigate distributions in the angles at which electrons travel when knocked away. In a new study published in EPJ D, M. Purkait and colleagues at Ramakrishna Mission Residential College in India have clearly identified particular areas where discrepancies arise between the angular distributions measured in theories and experiments.

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EPJ D Highlight - Uncovering fragmentation differences in chiral biomolecules

Different chiral forms of the dipeptide

By combining mass spectroscopy with further analytical and simulation techniques, researchers have revealed key differences in the fragmentation of dipeptide biomolecules with different chiral structures

‘Chirality’ describes the difference in structure between two molecules that are, or are close to being mirror images of each other. Although their chemical formulae are identical, these molecules have slightly different properties, making it useful for chemists to distinguish between them. The technique of ‘mass spectroscopy’ can provide detailed information about their complex molecular structures, but it is also blind to any differences between their chiral structures. In new research published in EPJ D, a team led by Anne Zehnacker at Paris-Saclay University combine mass spectroscopy with a range of other simulation and analytical techniques, allowing them to distinguish between two chiral forms of a dipeptide biomolecule.

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EPJ D Topical review - Review of experimental and theoretical research on positronium ions and molecules

Artist's view of the positronium negative ion and the positronium molecule.

The relativistic quantum theory developed by Dirac in the 1930’s is the cornerstone of Quantum Electrodynamics (QED), which has proved to be one of the most successful theories in physics. For example, measurements and QED calculations of the anomalous electron magnetic moment agree to 10 significant figures. Physicists now believe that QED can fully account for all effects that are mediated by electromagnetic interactions.

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Editors-in-Chief
David Blaschke, Thomas Duguet and Maria Jose Garcia Borge
Thanks to the referees for their helpful suggestions, and thanks to all EPJA Editorial and Production Office team for their professionalism and kindness! Thank you!

Danut Argintaru, Universitatea Maritima din Constanta, Romania

ISSN (Electronic Edition): 1434-601X

© Società Italiana di Fisica and
Springer-Verlag