Getting the brains to match our brawn

When it comes to accelerator science, Professor Carsten P. Welsch thinks there simply isn’t enough brain to go with our ever growing technological brawn. Here we learn of a training programme and some exciting projects that could fill this potential skills gap

Accelerator science is — together with advances in microelectronics — the driving force for innovation and economic prosperity of the future,” according to Dr Erich Griesmayer of CIVIDEC Instrumentation. The company is one of the industry partners in the oPAC (Optimisation of Particle Accelerator) programme, coordinated by the Cockcroft Institute, which is designed to build the knowledge-base and train the next generation of accelerator scientists.

One of the projects within oPAC aims to create a pocket sized particle accelerator, reducing the cost and increasing access to this exciting technology.

The importance of accelerator science to the European economy was underlined by a recent publication by the European Strategy Forum for Research Infrastructures (ESFRI), which included a roadmap identifying scientific infrastructures that are vital for the international competitiveness of European science. A key feature was the use of particle accelerator technology.

Europe is investing heavily in world-class facilities such as the X-ray Free Electron Laser (XFEL) in Hamburg which will allow studying biological and chemical processes on the shortest possible time scales and with unprecedented resolution; the European Spallation Source (ESS) in Lund, Sweden, which will be the highest power neutron facility in the world and push the limits in material sciences and nuclear physics; and the upgrade of the Large Hadron Collider (LHC) at CERN, Switzerland – already the highest energy accelerator and particle collider in the world.

In addition to scientific discovery, there is also a quickly growing market for accelerators in, for example, the security industry with applications such as cargo scanners, within healthcare for isotope production and cancer therapy, the food industry for increased shelf-life and the energy sector for novel reactor technologies.

More companies are involved in developing turnkey accelerator systems that are highly optimised to customer needs and can provide high quality beams for a wide range of applications. The result of all this activity is that the training of accelerator scientists and engineers is not keeping up with the demand.

Whilst a number of higher education institutions have recently established accelerator physics as part of their undergraduate courses, this whole research area is still pretty much unseen in the vast majority of universities across Europe. Currently, national initiatives alone, although pushing in the right direction, are simply not sufficient and more EU-wide collaboration needs to be established and supported. If this gap cannot be closed quickly it might have rather dramatic consequences.

Europe is investing heavily in large scale research infrastructures, but without greater investment in training there will simply not be enough researchers to commission, operate and continuously optimise the key research facilities. Furthermore, there is a quickly growing industrial sector with a high demand for accelerator experts. They are competing with research centres and universities for the best, widening the gap between supply and demand of researchers even further.

There have been initiatives to combat the training issues and these include the pan-European projects – oPAC addressing accelerator optimisation, and LA³NET covering laser applications at accelerator facilities, both part of the FP7 Marie Curie Initial Training Network (ITN) scheme and coordinated by the Cockcroft Institute, near Liverpool.

The Cockcroft Institute is named after Sir John Cockcroft who shares with Ernest Walton the Nobel Prize for splitting the atomic nucleus and is recognised as the pioneer of modern accelerator research. The institute is a collaboration between the universities of Lancaster, Liverpool and Manchester as well as the Science and Technology Facilities Council (STFC). It coordinates a number of pan-European programmes with industry partners and major research institutes, including CERN.

The programmes have succeeded in training over 40 fellows with the skills and practical experience required by commercial and research partners.

Indeed a core feature of these programmes is that the researcher training was set-up in close collaboration between universities, research centres and industry from the outset.

This has enabled a very intense 3-year training programme, where Fellows learn by carrying out cutting-edge research within an international collaboration of industry and research institutions. To give some examples of these research themes:

Pocket-sized accelerator The need to reduce the size and cost of research infrastructures is driving a trend for R&D to improve the efficiency of accelerators.

Laser acceleration offers considerable potential as a way to realise accelerating gradients that are 1000x higher than those that can currently be achieved with conventional radio frequency-based technologies. If lasers can be exploited to accelerate beams of charged particles in a controlled way then this approach could yield an enormous reduction in the complexity of an accelerator.

Within LA³NET there are several Fellows based in Germany, the UK and Spain that are studying cutting-edge technologies for laser acceleration. They have carried out experimental and numerical studies into some of the most advanced schemes and the international community is showing considerable interest in their findings.

An example is work by Yelong Wei from the University of Liverpool, who has been investigating the use of lasers in combination with dielectric microstructures to miniaturise a particle accelerator. These structures can be powered by laser energy very efficiently, generating large electric fields that can be used to accelerate charged particles to very high energies over a few centimetres.

Yelong is performing computer simulations to find the optimum geometry and material composition of these structures to maximise the acceleration efficiency. The aim is to develop an accelerator that will, one day, fit into the palm of a hand.

Minimising the size and cost of particle accelerators will expand their already vast range of applications and also make this technology more accessible to the international healthcare market allowing the benefits in cancer treatment to be more readily available.

Imaging living structures Another strand of research is the use of particle beams for imaging. X-ray imaging, although more familiar for taking photographs of bones, can also be used to obtain images of small fast moving objects such as proteins. In this case a much shorter and intense source of X-rays is needed.

LA³NET Fellow Andreas Döpp is based at CLPU in Spain and is developing a system to generate intense pulses of X-rays that last only a few femtoseconds (1 femtosecond = 0.000,000,000,000,001 seconds) that is, a few thousandths of a billionth of a second. With such X-ray pulses it will be possible to investigate protein folding in real time, which is essential for understanding diseases such as Alzheimer’s and cancer.

Conventional radiography is based on absorption of the X-rays by different materials with the denser calcium-rich bones showing lighter than other structures.

The use of X-ray pulses would allow the capture of images based on time taken for X-rays to traverse different materials, a process called phase radiograph. This would make it possible to take images of objects that are transparent to X-rays, and greatly increase the contrast of the radiographs.

Such bright and ultra-short pulses of X-rays are generated in the interaction of an electron beam with a high-power laser. Andreas is investigating different targets and injection schemes in order to optimise the electron energy or the X-ray energy and brightness, and to determine whichever is most effective.

Measurement of moving targets Particle beams are also able to measure the velocity of moving objects with greater accuracy.

Ms Alexandra Alexandrova is a Fellow at the Cockcroft Institute and she joined from the Moscow Engineering Physics Institute, in Russia, where she already had a background in laser R&D and was ideally placed for a project on laser self-mixing.

Alexandra uses an interference effect caused by a moving object to measure its velocity. The beauty of her method is that this approach can be applied to a solid object, a fluid or a gas. A potential outcome from this project is a novel diagnostic tool to measure the velocity and density profile of ultra-sonic gas jets. Her technique shows great promise as a compact, cheap and versatile sensor for many other applications.

The ground-breaking research supported by the oPAC and LA³NET programmes has resulted in large number of research articles and invited talks.

This means participating institutions have benefitted through first class research and additional visibility gained through presentations given by the Fellows at numerous international events.

The intention is also to create well-rounded Fellows with the skills they need for the future. So in parallel with the research, they have been given access to training in career skills, such as project management, presentation techniques and scientific writing, along with expert courses in a number of research areas. This unique combination provides them with an ideal basis for their future careers, irrespective of whether this would be in academia or industry.

In addition, a key feature of the programmes has been the development of a strong and international contact network of individuals with an interest in accelerator science. It is very likely that these links will lead to many new projects in the future.

Through the networking, fellows are well aware of the research opportunities at partner institutions. For example, the intra-network secondment scheme has allowed them to gain work experience at other network nodes, in this way they can extend their research experience and this might develop into future employment with a partner. All partners have strongly supported this approach to developing the Fellows and the comprehensive and unique training it offers is only possible because of their fantastic support and commitment. The end result is a pool of highly skilled, very employable researchers.

Although oPAC and LA³NET are now drawing to a close they have shown to have impact well beyond the initial consortia. The multi-factorial approach to training has been adopted with other institutes and outreach activities by fellows have created more awareness about the importance of accelerators beyond the academic community.

An example of this is an outreach symposium ‘Accelerators for Science and Society’ held in the Liverpool Convention Centre on 26 June 2015 with world-renown speakers. This event will showcase the outcomes from the accelerators-based research already achieved and also show to a wider public the benefit of funding training in this exciting technology sector.

Research institutions are increasingly asked to demonstrate impact. One of the lasting impacts of the LA³NET and oPAC programmes will not only be competitive advantage it has given to European companies but also the evolution of a new model for the way that researchers are trained that ensures that they are highly employable and sought after when they leave academia.

We hope that there will be more particle accelerator-oriented training networks and it will be possible to give similar opportunities to future generations of researchers.

The author: 

Professor Carsten P. Welsch is a faculty member at the University of Liverpool and a member of the Cockcroft Institute of Accelerator Science and Technology. He leads the university’s accelerator physics group.