CERN Accelerating science

3D Photo Composition of the Planned FAIR Facility at GSI (Image: FAIR/Jan Schäfer)

Researchers at GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany have presented preliminary results for the integration of accelerator facilities into Virtual Power Plant (VPP) networks within the scope of the EuCARD-2 project.

Virtual Power Plants (VPPs) are networks that aim to optimise the production, storage and use of energy. They are comprised of renewable producers such a wind turbines and solar panels, storage facilities such as battery stations, and both public and industrial users. The networks aim to ensure better availability and reliability for consumers.

Dr Jens Stadlmann, Vice Machine Coordinator of SIS18 at GSI, said: “Accelerators are large and variable power consumers which makes them eligible candidates for VPP.”

The GSI team analysed the energy consumption of the accelerator complex and found a 3-6 MW difference between operation and shutdown. This meant the shutdown of the equipment could be scheduled during times of high-energy demand by identifying switchable loads.

The FAIR Facility

In an effort to consider the feasibility for future accelerator complexes, the GSI team studied the SIS100, the main synchrotron of the future Facility for Antiproton and Ion Research (FAIR).

The FAIR synchrotron will be able to work in very flexible cycles with three different modes of operation: Cycles A, B and C. Cycles A and B are regular modes of operation, which have similar dynamic loads and safety margins but Cycle C has much higher dynamic loss and is not planned as a regular mode of operation.

Experiments could schedule operation cycles with high dynamic loss around times of low energy demand. Next, power providers could make use of the whole facility as part of a VPP scenario by actively switching accelerator facilities to a low energy consuming cycle when general power demand is high.

Challenges for accelerators in VPP networks

Potential energy management schedules for accelerators must be considered carefully, as researchers may be expected to wait significant periods for the facility to be switched back to high-energy operation. Longer operating times may be required to compensate, which has its own impact on energy consumption and staff and operating costs.

In addition, the operation of the cryogenic system during low-energy may present a technical challenge for facility operators.

The SIS100 magnets are cooled by a two-phase helium system, whereby liquid helium extracts heat from the magnets and is evaporated back into a gas before being transported back to the surface of the facility.

If an accelerator facility is switched to low-energy operation, the level of cooling must be adjusted accordingly. At a lower energy magnets will produce less heat, so not all of the liquefied helium can be evaporated.

To recoup all of the deployed helium, facilities may need to install heaters or a method of pumping the liquid back into the feed box.  Using heaters means the energy consumption of the cryo plant will stay relatively constant for all modes of accelerator operation. Significant changes must be made at the cryosystem to realise lower energy consumption during cycles of low dynamic load.

Next steps for accelerators and VPPs

Allowing power suppliers to switch accelerator facilities from high to low energy during times of high energy demand adds a layer of complexity and risk to facility operation.

Before accelerators may be fully integrated into VPP networks the cryogenic systems require further development, safety measures must be assessed and the facility must comply with additional regulations from the power network operators.

The longer operating times needed to compensate users for a loss of beam time may result in similar or higher energy consumption, and the costs for the manpower and operation of these facilities may also be higher.

Trialling for the expansion of VPP networks with accelerator facilities may allow researchers and power suppliers to identify potential obstacles to further use, which in turn may present future avenues of research and development.

“The technical and organisational obstacles which have to be overcome to qualify a complex machine like an accelerator for a VPP seem to be transferable to other scenarios und thus be of general interest for society,” said Dr Stadlmann.

ADS research workshop held at CERN
by Jennifer Toes (CERN)

Visualisation of the European Spallation Source (ESS), a neutron source driven by a linear accelerator  (Image: ESS)

In February 2017, over 70 high-energy physicists visited CERN to attend and present at a workshop on the “Status of Accelerator Driven Systems Research and Technology Development”.

Accelerator Driven Systems (ADS) refer to the use of particle accelerators in combination with subcritical nuclear reactor cores to allow fission to be sustained through the production of neutrons by spallation.

ADS have a variety of applications, ranging from the transmutation of nuclear waste, to energy generation and production of isotopes for use in cancer treatments.

The workshop, organised by WP4 of the EuCARD-2 project, focused on the following ADS-related topics: international ADS programmes, socio-economic impact of ADS, accelerator operation in ADS, coupling experiments, and future challenges for ADS research and development.

“The workshop has gathered a wide and active community, whose interest is demonstrated by the many programs that are on-going in the world. Accelerator technologies in ADS can provide important contributions to society,” said Marcello Losasso, member of the Scientific Programme Committee.

He continued: “The old cyclotron/linac opposition led to interesting discussions during the workshop. In particular, cyclotron technology was assessed as a worthwhile route of investigation for industrial applications of ADS.”

In fact, all current ADS projects across the world are based on linear machines, and therefore researchers already have benchmarks concerning their cost, time to market and technical characteristics.

This is not the case for high power cyclotrons, whose data are limited and not often as up-to-date.

Further presentations were made on the ADS programmes across Europe and in China, Japan, the United States and Ukraine. The international ADS efforts include a wide range of R&D into applications such as: nuclear waste elimination, energy production, neutron spallation sources, and the production of isotopes and high intensity beams for fundamental research.

International cooperation was stressed for the further development of ADS, which may present a challenge due to conflicting national goals in ADS R&D.

The critical aspects of accelerators for use in ADS were also discussed, touching on their technical requirements, economic feasibility and licensing issues. Ultimately, the ADS projects currently existing and in development across the world seem to suggest they are technically feasible. However, the industrial deployment of the technology depends on many interlinked factors as the licensability and cost.

Presentations on coupling experiments demonstrated that zero power facilities offer good flexibility and simplicity of execution, and are therefore of critical importance to gather validation measurements and facilitate the licensing processes. Benchmarking can also be improved by using multiple approaches to gather parametric measurements.

In addition, speakers detailed a new design for a high power target and reported on the new spallation target prototypes and sources.

Of course, as with any emerging field, new and innovative research and development is crucial. As such, the workshop also featured talks on new projects and approaches for the future.

This included CYCLADS, a recently submitted EU FET-OPEN project (not-yet approved) whose consortium, coordinated by CERN, includes major industrial and academic European partners such as iThEC, PSI, AIMA-Dev, HNI, ENEA, N-21, ASG. The aim of the project is to establish the conceptual design of an innovative high-power, compact and cost-effective cyclotron to be used for the transmutation of nuclear waste. The project should be able to provide fresh economical data and new technical opportunities on the benefits of cyclotrons as an option for an ADS.

The workshop closed with summary reports from the Session Chairmen highlighting the current status and future challenges of ADS around the world.


eeFACT2016 held in Daresbury UK
by Ralph Aβmann (DESY), Peter Ratoff (Cockcroft Institute) and Frank Zimmermann (CERN)

eeFACT2016: Participants of eeFACT2016 on the Daresbury campus (Image: Cockcroft Institute)

From 24 to 27 October 2016, accelerator experts from around the world gathered in Daresbury, UK, to discuss the state of the art, the challenges and the future directions for circular high-luminosity electron-positron factories.

The eeFACT2016 workshop was organized under the umbrella of ICFA and co-sponsored by the EuCARD-2 “Extreme Beams” accelerator network. An international committee co-chaired by Yoshihiro Funakoshi from KEK, Qing Qin from IHEP, and Frank Zimmermann from CERN had assembled a programme reflecting the breadth of the ongoing worldwide efforts.

The Cockcroft Institute, with the hospitality of its Director Peter Ratoff and the outstanding support from Liz Kennedy and Sue Waller, proved a perfect host for this event. Participants hailing from China, Italy, Japan, Russia and the United States appreciated the smooth organization, wonderful venue, plus the chance to visit nearby historical Chester. The timing of the workshop could not have been better, including for the weather: during all four days the sun was shining, in what seemed like a British Indian summer.

Circular colliders have been a frontier technology of particle physics for half a century, with more than a factor 10 luminosity increase every ten years. Several lower-energy factories are in operation, continually improving their performance: BEPC-II at IHEP Beijing, DAΦNE at INFN Frascati, and VEPP-2000 at BINP Novosibirsk.

The Super-B-factory SuperKEKB, presently under commissioning in Japan, will be the next big upward step in luminosity. Among other future projects, a Super-charm-tau factory is being developed in Russia, while two ambitious highest-energy circular Higgs-Z-W (and top) factories are under design: the Circular Electron Positron Collider (CEPC) in China, and the electron-positron version of the Future Circular Collider (FCC-ee) on the Franco-Swiss border.

At eeFACT2016, DESY leading scientist Ralph Assmann recognized the continuing high level of innovation, even after an already 50-year long history of colliders, and a wealth of novel concepts. Over the last couple of years, several game-changing schemes have been introduced, for example colliding beams with a crab waist, large Piwinski angle and extremely low emittance.

The crab-waist concept was presented by its inventor Pantaleo Raimondi, now Director of the Accelerator and Source Division at the ESRF. This crab-waist scheme has already demonstrated its great merits in actual beam operation at DAΦNE. Other novel concepts include the use of a double ring or partial double ring, magnet tapering for the energy sawtooth, top-up injection, cost-effective 2-in-1 magnets, ultra-low beta function, “virtual crab waist” and asymmetric interaction-region optics.

The last two concepts were rather recently developed by Katsunobu Oide, former Director of KEK’s Accelerator Laboratory. Upcoming colliders like SuperKEKB will test the limits of these new schemes and manifest their positive impact. The upgraded VEPP-2000 collider will push the concept of round beams. In parallel much progress is being made in the design and operation of storage-ring light sources. An excellent review by ESRF’s world expert Dieter Einfeld revealed numerous topics of common interest with the collider world. Lastly, not to be forgotten is the built-in synergy of a future large circular high-energy lepton collider, such as CEPC or FCC-ee, with a subsequent hadron collider installed in the same tunnel, called SPPC and FCC-hh, respectively – as was highlighted by Alain Blondel from the University of Geneva.

The projected performance of the future factories is further lifted by a dramatic progress in accelerator technology. An entire session, convened by JLAB’s Bob Rimmer, was devoted to the radiofrequency (RF) system, which, working in continuous wave mode, needs to transmit a large power and support high beam currents at a high efficiency.

An essential component of this system is superconducting RF (SRF) cavities, whose overall efficiency is revolutionized by novel production schemes such as nitrogen doping and thin-film Nb3Sn coating. Several novel klystron concepts are on track to boost the power conversion efficiency of RF power generators. Thanks to this type of innovation, when compared with previous colliders the next generation can be considered truly green facilities.

The luminosity-energy plane of past, present and proposed future e+e- colliders. Combining successful ingredients of recent colliders and adding further innovative concepts promises extremely high luminosities at energies ranging from the Z pole to the tt threshold as illustrated by the plotting symbols for FCC-ee and CEPC (Image: Marica Biagini and Frank Zimmermann).

Alex Chao, an eminent physicist from SLAC, summarized that with performance being pushed so hard at the future factories, more subtleties that were unimportant in the past now arise. Indeed new effects keep being discovered for the beam-beam effects, such as the requirement of crab waist, residual nonlinearities after the crab waist cancellation, beamstrahlung, 3D flip-flop instability, interplay with lattice nonlinearities, and the possible interplay with collective effects. Alex Chao underlined that the beam-beam issue will become more critical than ever.

The large future collider concepts FCC-ee and CEPC build upon the recent innovations and are planning to exploit their full potential at the precision frontier, measuring the properties, couplings and decays of the Higgs and several other high energy particles with extreme accuracy. New ideas for compact low-energy crab-waist colliders, possibly based at universities, are emerging as well and these might offer attractive alternative paths for research and science.

The ARIES project has been approved by the European Commission under the Horizon 2020 Framework Programme for Research and Innovation and will receive €10M in EU funding as requested in its proposal.
The full title of the project is Accelerator Research and Innovation for European Science and Society. It will serve as the spiritual successor to the EuCARD-2 Integrating Activity project, which is due to end in April 2017. The start date for ARIES is yet to be agreed upon, but is foreseen for May 2017, to allow a smooth transition between the two projects.
The total budget of the project will be €24.8M over the four-year study period, which includes the EU contribution and €14.8 M from the involved beneficiaries. The overall evaluation score of ARIES was 14.5 out of 15. This is the highest score compared with previous EU funded accelerator R&D projects such as CARE, EuCARD and EuCARD-2.
ARIES aims to develop novel concepts and improve existing accelerator technologies; to provide access to top-class accelerator research and test infrastructures to European researchers and industry; to further integrate the European accelerator community; and to develop a joint strategy towards sustainable accelerator S&T.
ARIES will bring together 41 beneficiaries from 18 different European countries, one International European Interest Organization (CERN) and one European Research Infrastructure Consortium (ESS). The beneficiaries are based in the following 18 countries: Austria, Belgium, France, Germany, Hungary, Italy, Latvia, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
The evaluators of the project highlighted the clarity of the project’s innovation strategy, the integration such a large variety of partners, the extent of the Transnational Access programme, the intended creation of an e-learning course, the proof-of-concept fund, and the development of compact accelerators as particular areas of interest within the proposal.
During its grant preparation, the Project Coordinator, Maurizio Vretenar (CERN), will agree on a start date for the project with the European Commission and a kick-off meeting for all project collaborators will be arranged.

New milestone for High Temperature Superconductors at UNIGE
by Carmine Senatore & Panos Charitos

Details of the innovative superconducting coil, conceived and manufactured by researchers from UNIGE and Bruker BioSpin. (Image: © L. Windels, UNIGE)

High field superconducting magnets are the enabling technology for particle colliders, modern magnetic medical imaging, magnetic resonance spectroscopy and fusion reactors. To further push the boundaries of science, enhancing resolution or energy, these devices call for ever increasing magnetic fields. However, solenoidal coils built with the Low Temperature Superconductors (LTS) NbTi and Nb3Sn are limited to around 23.5 T while accelerator dipole magnets based on LTS will most likely reach their ultimate performance at about 16 T.

Recent progresses in the technology of High Temperature Superconductors (HTS) and, in particular, in REBa2Cu3O7-x (REBCO, RE = rare earth) coated conductors (CCs) have paved a way for the development of all-superconducting solenoids capable of generating fields in the range of 30 T, i.e. well beyond the limits of the present technology. However, the development of REBCO magnets still poses several fundamental and engineering challenges.

Carmine Senatore, Professor at the University of Geneva (UNIGE) is actively working in the study of applied superconductivity and through EuroCirCol is working for the development of high-field magnets for a future circular collider based on Nb3Sn under the scope of the FCC Study and EuroCirCol project. Senarore, also works on the development of HTS magnets. He is deputy leader of one of the working packages of EuCARD2 (WP 10.2) exploring different HTS conductor concepts and aiming to manufacture conductor prototypes to feed the HTS accelerator magnet demonstration program, which is the scope of WP10.

Recently his research group in the University of Geneva achieved the goal of generating a magnetic field of 25 T and, thus, obtaining the European record of highest superconducting generated magnetic field. Researchers at UNIGE worked closely with Bruker BioSpin to combine a Bruker laboratory magnet producing 21 T, already installed at UNIGE, with an innovative superconducting insert coil that allowed to increase the field by an additional 4 T. This means that in total, a field well beyond the 23.5 T reachable with conventional superconducting coils could be generated.

Piotr Komorowski, R&D engineer at Bruker and Professor Carmine Senator (UNIGE) pointing to the record field of 25T (Credits: UNIGE)

Concerning the scope of the project, Senatore says: «high magnetic fields are an indispensable tool for research in physics and material science as well as medical applications. This technological need represents the driver for the development of HTS, as they are the only means to generate fields well above 20 T». Riccardo Tediosi, manager of Bruker BioSpin’s Superconducting Technologies group adds: "the successful test of the 25 T coil represents a positive test-bench of ideas that we are developing for the next-generation HTS-based NMR magnets. We see that commercial breakthroughs in this field are at reach and 2017-2018 is going to be a very exciting period for Bruker and the NMR community."

The REBCO tapes used to achieve the 25 T in the solenoidal magnet are also studied under EuCARD-2 to build a dipole demonstrator able to generate 5 T in standalone configuration. It is then planned to use the same dipole demonstrator in a background field allowing to reach fields of up to 20 T. The 20 T target in the dipole compared to the 25 T reached in the solenoid should not generate confusion. Compared to solenoids, accelerator magnets are different “animals”: they need compact windings for reason of efficiency and cost, very high currents to ease protection, and they experience large forces transverse to the cable. Simple electromagnetics tells us, they require the double of ampere-turns to generate the same field.

However, there is much in common between the 25 T development based on REBCO coils and the goals of EuCARD-2. Senatore explains: We investigated the electrical, mechanical and thermo-physical properties of commercial REBCO tapes from all over the world. The results of these studies guided the choice of the commercial tape to be used for our insert coil and at the same time provided important inputs to the development of the conductor for the dipole prototype of EuCARD-2. The EuCARD-2 dipole will use these tapes in the form of a Roebel cable, a century old technology used for electrical machines. First winding tests have been performed, in various geometries, and a small coil is presently in test at CERN to validate the manufacturing process that will be used for the final magnet, planned for 2017. 

EuCARD-2 3rd Annual Meeting highlights
by Jennifer Toes (CERN)

EuCARD-2 Project Coordinator, Maurizio Vretenar, opens the 3rd Annual Meeting at University of Malta, April 2016 (Credit: CERN)

In the last week of April 2016 international collaborators of the EuCARD-2 project gathered in Malta to share their news and results from the past year.

The project’s 3rd Annual Meeting was hosted by the University of Malta, one of the project participants, and was attended by over 80 participants from 13 different European countries, the United States and Japan. The opening address to the meeting was given by the Foreign Minister of Malta  and the French ambassador joined project participants at the evening dinner reception.

The meeting consisted of a series of plenary presentations from each Work Package (WP) to disseminate their work to other WPs, of invited presentations on recent important developments in accelerator R&D and dedicated sessions for members of each WP to meet and discuss results most relevant to their work.

The Networking activities (WPs 2-7 focused on catalysing innovation, energy efficiency, accelerator applications, extreme beams, low emittance rings, and novel accelerators) provided updates on their work from the past year, including the results of workshops and meetings set up by individual WPs.

Extreme Beams analysed the future operation of the LHC and effects relevant for future high-intensity storage rings, colliders, boson factories and lepton-hadron colliders. Low emittance rings identified and analysed techniques for increasing the brilliance of synchrotron light sources. Novel accelerators presented the strategy for the design and construction of a first pilot plasma accelerator laboratory in Europe. Energy efficiency presented a new generation of high-efficiency Radio-Frequency devices. Finally, Accelerator Applications presented the results of investigating applications of accelerator technology which may have practical use in society (such as waste water treatment, radioisotope production with compact accelerators, and novel techniques and delivery systems for cancer therapy).


All participants in the EuCARD-2 Annual Meeting at University of Malta

The three Transnational Access (TA) activities (WPs 8 and 9, ICTF at STFC and the HiRadMad and MagNet facilities at CERN) presented updates on the status of the uptake of the access units offered and the most recent developments made at the facilities. All facilities have proved popular and are already approaching the total number of access units offered within the proposal.

Finally, the four Joint Research activities (WPs 10-13, focused on future magnets, collimator materials for high density energy deposition, innovative radio frequency technologies and novel accelerator techniques) demonstrated their substantial progress in the development of advanced accelerator technologies over the past year.

These results included progress towards the first prototype magnet based on High-Temperature Superconductor (HTS) technology, and the production and testing of HTS tapes and cables. In addition, new material grades which may improve performance against irradiation and high-energy deposition for the LHC upgrade were identified and validated. New thin film superconducting coatings were developed and tested. Important achievements were registered in the experimental validation of Novel Acceleration Techniques.

As well as the spectrum of research news and results presented during both plenary and parallel sessions, during the meeting two outreach talks were given to the public by Maurizio Vretenar, Frank Zimmermann and Ralph Assmann. Both events were well attended. In addition, the Maltese television station ‘TV Malta’ invited the Project Coordinator and attendees from the University of Malta to be interviewed for their breakfast broadcast.

EuCARD2 WP3 Workshop on Proton Driver Accelerator Energy Efficiency
 by Jennifer Toes (CERN) 

The Paul Scherrer Institut (PSI) in Villigen, Switzerland hosted a workshop on the energy efficiency of proton driver accelerators in late February.

Proton driver accelerators have a broad range of applications, ranging from neutron sources over accelerator driven systems for transmutation to particle physics, muon and neutrino production. As these accelerators consume large amounts of electricity, improving their energy efficiency is crucial in addressing the economic and environmental concerns of both the public and research funding agencies.

The goal of the workshop was to bring together experts to collaborate and exchange ideas and research in pursuit of higher efficiency proton drivers. Over four sessions, the participants discussed four topics of particular interest: beam targets, RF generation, accelerator concepts and auxiliary systems..

The workshop identified several promising technologies for improving the energy efficiency on which future R&D should be focused:

Neutron Spallation Targets and associated components like moderators and neutron guides have a potential for efficiency improvements by large factors for certain applications. The studies on a second target station for SNS give an example for such optimizations.

Magnetrons as RF sources exhibit a high efficiency but currently aren’t well suited for use in accelerators due to their instable phase and amplitude behaviour. Ongoing studies at Fermilab show promising results to overcome these problems. Eighty years after its invention the Klystron represents a matured and widely used concept. Nevertheless, new ideas on improving the electron beam dynamics in klystrons may boost the efficiency towards 90%.

The cryogenic systems used in continuous wave superconducting linacs represent a major contribution to the energy balance of the entire facility. The recent success in producing High Q0 Superconducting Cavities may help to reduce the cryogenic power significantly.

Energy Management should be coordinated in a comprehensive way at larger research facilities. Important parts are cryogenic plants but also conventional cooling and air conditioning. With large fluctuations from sustainable power production flexible and intelligent operating scenarios may become important for energy intensive research facilities.

Mike Seidel, the workshop chair said: “A common meeting for experts on such diverse fields as beam targets, RF generation or conventional facilities was an experiment. But all these areas contribute to energy efficiency. We received a lot of positive feedback from the participants and finally one can say: the workshop was a success and the community will benefit from the outcome.”

The “kladistron project” for high-efficiency klystrons
By Juliette Plouin, Antoine Mollard and Franck Peauger (CEA)
Figure 1: Schematic view of the standard 5 GHz TH2166 klystron (top) and of the 5 GHz kladistron (bottom)

Under the framework of EuCARD-2, the study of high efficiency - high frequency klystrons is in progress in close collaboration between CEA Saclay and Thales Electron Devices. The “Kladistron project” aims to design a high-power 12GHz klystron to be used in CLIC.  

The objective of the Innovative RF Technologies activity is to propose affordable and reliable solutions to increase efficiency and thus save high amounts of energy in accelerators. These will be essential for future testing capabilities for the CLIC accelerating structures. To achieve this, a new klystron concept is required. A new electron beam bunching technique has been proposed to increase the beam-to-RF interaction efficiency above the state-of-art limits (> 65%). This method is inspired by the Radio Frequency Quadrupole (RFQ) based injectors which bunch adiabatically a CW (continuous mode) hadron beam with more than 95% transmission. The new proposed device, called kladistron, includes a large number of bunching cavities (typically 15 to 20, which is twice as many as in a conventional klystron) separated by short drift tubes. This enables giving a “soft kick” to the beam in a large number of cavities instead of a “large kick” to the beam in a small number of cavities. The coupling between these cavities and the beam (r/Q) is lower than in a standard klystron. Preliminary calculations at this frequency, made with a 1D code, have given efficiencies around 60 % with 10 cavities and 70 % with 20 cavities.

The first experimental tests will be realized on a 5 GHz demonstrator, constituted of a standard klystron from Thales, the TH2166 (6 cavities, CW mode, 4.9 GHz, 26 kV, 4.3 A, efficiency 50%), in which the intermediate cavities are modified. All the other elements: gun, solenoid, collector, input and output cavities and window, are kept as is and the 4 intermediate cavities are replaced by 14 new cavities with lower r/Q. The overall length is kept the same, to fit in the existing solenoid, and the new cavities are very close to each other. The principle is shown in Figure 1, where the cavities pattern is placed on a schematic klystron for both standard klystron and kladistron. The calculations with Magic (2D Particule In Cell code) give an efficiency equal to 50% (as expected) for the standard klystron, and equal to 60 % for the kladistron. The beam shape given by Magic at the end of the simulation is also shown in Figure 1. One can see that the beam bunching is softer for the kladistron than for the standard klystron

The design of this kladistron demonstrator is nearly ready, and the fabrication and tests are planned in 2016. The aim is to verify that a higher number of low-coupled cavities lead to higher efficiency, all other elements being the same. Once this principle is being validated, it will be possible to reach higher efficiencies with thorough optimization of the electron bunching.



 Delivering impact of particle accelerators
 by Agnes Szeberenyi (CERN)
APAE kick-off. Courtesy of University of Huddersfield

“The Applications of Particle Accelerators in Europe” project initiated by EuCARD-2 kicked-off with a very intense 2-day event in London in mid-June.

More than 90 researchers from various scientific fields gathered at the Royal Academy of Engineering in London mid-June to share and learn about each other’s area of expertise with particle accelerators, clearly demonstrating that there is more to particle accelerators than the Higgs. The event featured expert talks from academia, industry and medical representatives on the main application areas of accelerators including industry and environment (ion and electron beams), security, health, photonics, neutron scattering and energy.

The goal of this project is to demonstrate the potential of particle accelerators and the importance of continuing their development, and deliver a report to be presented to European funding bodies and policy makers. The 2-page summary of the document will be focusing on accelerator research at country level and will be tailored (including translation) to many of the European countries.

The next steps are now in the hands of the session conveners to organize a structured input from their communities demonstrating the impact and challenges of accelerator research and applications. The target publication date is end of 2016.

If you could not attend the meeting but would be interested in contributing to the document, please get in touch with the organizers or the session conveners.  



 Wake field monitoring to improve FEL performance
 by Micha Dehler (PSI), Nicoleta-Ionela Baboi (DESY)

Down stream end of X band structure with wake field monitor pickup. Image credit: PSI

Detecting structure tilts in the spectral density of a WFM signal. Image credit: DESY

Beam degradation due to RF structure misalignments poses a challenge in the operation of ultra high brightness FELs. Wake field monitors offer a direct way to diagnose and correct these effects.

Misalignment between the beam and RF accelerating structures lead to transverse wake field excitation which degrades the beam quality. Wake field monitors (WFMs) are devices which couple these fields and their components, the Higher Order Modes (HOM), and therefore enable their reduction. This is of special interest in modern free electron lasers where the beam quality is of extreme concern.

Two teams from EuCARD2 WP12 are exploring this field, one developing a front end for the WFMs of a 12 GHz RF structure used for the SwissFEL and the other dealing with 1.3 and 3.9 GHz superconducting cavities of the European X-ray Free Electron Laser (E-XFEL).

The RF front end for the 12 GHz structure employs an innovative electro-optical down conversion scheme of the HOM fields, which is attractive in terms of band width, radiation hardness and the capability of transporting signals over kilometers. During first beam tests, by using a spectral analysis method, the system could identify the beam to structure offset and tilt. With the resolution improving to micron range, the device is expected to show even finer details such as structure bends or kinks.

Until recently, the HOM based system at FLASH was only used for beam alignment, but showed drifts over time as a beam position monitor. A way to stabilize the signals has been found based on a frequency domain analysis, such that a resolution of few microns was preserved over several months.  A new direct sampling approach for the E-XFEL 1.3 GHz cavities reduces the number of electronic components and therefore their  drifts with time. At the same time these are the first electronics to offer the possibility of monitoring the beam phase with respect to the RF pulse, important for optimization of the longitudinal beam properties.