accelerating-news-arc.web.cern.ch - issue 14

Delivering impact of particle accelerators

Livia Lapadatescu — Mon, 22 Jun 2015 15:05:01 +0000

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.

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issue 14

A gender balance roadmap for FCC

Livia Lapadatescu — Mon, 22 Jun 2015 14:38:44 +0000

A gender balance roadmap for FCC
by Johannes Gutleber (CERN) with Livia Lapadatescu (CERN)

Video produced by the FCC gender equality working group, aimed at encouraging women to take part in the project. Image credit: FCC

During the FCC Annual Meeting which took place in Washington DC in March 2015, a dedicated session was organized with the objective of laying the foundation towards the establishment of a gender balance roadmap for the FCC Collaboration.

The Future Circular Collider (FCC) Study is an international endeavour that fosters cross-disciplinary research involving many knowledge domains. This setup represents an ideal opportunity to reinforce the representation of women in the European science landscape and to stimulate the attractiveness of technical and scientific projects among them. Furthermore, the FCC study through the EuroCirCol Horizon 2020 project is committed to work towards equal representation of women and men in leadership positions.

About 60 participants, including senior scientists and decision-makers from CERN and other institutes involved in the FCC Collaboration, took part in the Gender Equality Session during the FCC Annual Meeting. The session was organised to balance the sharing of experience from representatives of the engineering and physics world with best practices established by government and funding agencies and was chaired by the CERN Diversity Programme Leader, Geneviève Guinot, and the FCC Deputy Coordinator Frank Zimmermann.

Prof. Fabiola Gianotti, CERN Director-General designate, opened the session with a short introductory Q&A session and emphasized the importance of providing an environment of equal opportunities for men and women and monitoring its evolution.

Other speakers included Dr. Theodore Hodapp, Director of Education and Diversity of American Physical Society (APS), Dr. Kate Duncan, current IEEE Women in Engineering (WIE) Coordinator for the Eastern US region, Ms. Anne-Marie Horowitz from the US Department of Energy (DoE) and Dr. Jessie DeAro, from National Science Foundation (NSF). They outlined their organisations’ visions and plans to ensure gender equality.

The session closed with the projection of a video produced by the FCC gender equality working group, aimed at encouraging women to take part in the project (see video above). The video is a pilot towards further development of other FCC gender-targeted communication strategies.

“The session marked the starting point towards a common task force”, says Geneviève Guinot, “The fact that this effort is part of the study right from the beginning is a wonderful opportunity. Next steps will include the structuring of the gender equality taskforce to make our actions a sustainable part of the FCC Collaboration”.

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First hardware for HL-LHC interaction region magnets

Livia Lapadatescu — Mon, 22 Jun 2015 08:24:51 +0000

First hardware for HL-LHC interaction region magnets
by Ezio Todesco (CERN)

The coil of the sextupole corrector
Courtesy of G. Volpini and LASA laboratories

The mirror QXF entering the FNAL test station
Courtesy of G. Chlachidze and US-LARP

The Interaction Region (IR) of the HL-LHC project will be made of nine different types of new magnet, relying on three different technologies (Nb3Sn and Nb-Ti with Rutherford cable, and superferric magnets with Nb-Ti coils).

These magnets are in the design and prototype phase, developed by five international collaborations: US-LARP, CIEMAT (Spain), CEA Saclay (France), INFN-Milano LASA laboratories and INFN-Genova (Italy), and KEK (Japan). The HL-LHC design study is now approaching completion: the conceptual design is nearly finished, engineering is in progress and the first hardware that will be used in the prototypes is being manufactured and tested. This is a very exciting phase as the project shifts from paper to hardware.

In April 2015, the winding and impregnation of the first coil of the superferric sextupole corrector (see image above-left) was completed. As a stand-alone coil it was successfully tested in INFN-LASA laboratories. This collaboration has won the race towards the first test of a component of the HL-LHC interaction region magnets. The coil had a first quench at 80% of short sample limit, and reached 91% after 3 quenches, at 2.5 K. In these correctors, the operational current is set at 60% of short sample limit.

In May 2015, the first short coil of the Nb3Sn quadrupoles, manufactured by the LARP collaboration, was tested in a mirror configuration at FNAL, US. The coil had a first quench at 70% of short sample limit, a second one at 76%, and reached 90% after 20 quenches. The triplet will operate at 75% - this value has been recently reduced from the original 80% value to add some margin, following the advice of the review committee held in December 2014 and chaired by Dr. A. Yamamoto (KEK).

Since the beginning of the year, coil winding tests are going on both in KEK, for the 5.6 T Nb-Ti separation dipole (D1), and in Saclay, for the 115 T/m gradient Nb-Ti quadrupole. In KEK, an iteration of the design of the iron yoke has been performed to guarantee a better alignment of the dipole field during assembly. In CEA, first tests have confirmed the correct geometry of the end spacers and of the coil components.

The next step is the test of the Nb3Sn quadrupole short model in autumn 2015, made up of two CERN coils (just shipped to the US) and two LARP coils. At the end of the year a test of the first corrector sextupole is foreseen in LASA, and a test of the first short model of the separation dipole will be carried out in KEK, Japan.

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Hollow electron lenses for enhanced LHC beam collimation

Livia Lapadatescu — Fri, 19 Jun 2015 11:09:45 +0000

Hollow electron lenses for enhanced LHC beam collimation
by Stefano Redaelli (CERN) with Emma Cooper (STFC)

Design of the LHC hollow e-lens. Courtesy of D. Perini for the EN/MME team at CERN

Loss spikes have already affected the operation of the LHC, and control of beam losses is recognised as a critical concern for performance at higher beam energies and intensities.

Hollow electron lenses are the most promising of a number of methods being considered to improve the beam collimation system, and are expected to boost the performance of the LHC and of its High-Luminosity (HL) upgrade through active control of halo particles’ diffusion speed and tail population. This is achieved with a low-energy, intensity-modulated hollow electron beam that runs co-axially to the circulating hadron beam, over a few meters, and acts on the halo particles at large transverse amplitudes without perturbing the beam core. Particles outside the core that see the electromagnetic field of the electron beam are driven unstable and disposed of by the present collimation system at controlled loss rates, rather than at larger loss rates and at unpredictable moments.

Following a successful experience at the Tevatron, where a hollow e-lens was used for collimation beam tests for the LHC, a conceptual design of a hollow e-lens optimized for the LHC was produced. At CERN, this is an effort across all departments of the Accelerator and Technology Sector. The conceptual design is rapidly evolving into a technical design for implementation into the LHC. While a detailed timeline for deployment will be established after accumulating some operational experience at 6.5 TeV, the aim is to prepare a technical design by the end of 2015 in order to be ready for LHC needs beyond Long Shutdown 2.

The present baseline design of the LHC hollow e-lens was worked out in collaboration with the Tevatron team. The electron beam parameters achieved in a test stand for LHC collimation studies at Fermilab indicate that a 5 A electron beam current can be achieved with a 2.5 mm radius gun at 10 kV. In order to stabilize the hollow beam and squeeze its inner radius to the required dimensions around the ~300 micron rms size hadron beams, a precise superconducting solenoid of up to 6 tesla is required. An ‘S’ shape design, with injection and extraction of the electron beam on opposite sides of the proton beam, is proposed to compensate edge effects that might otherwise perturb the beam core particles that ‘see’ asymmetric e-beam distributions at the injection and extraction locations.

Scheme illustrating the conceptual integration of a hollow elens in the present collimation system hierarchy. This device controlled the loss rates while the standard collimation remains in place to dispose of the halo particles. Credit: CERN

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issue 14

Forging links between industry and fundamental science

Livia Lapadatescu — Fri, 19 Jun 2015 09:34:10 +0000

Forging links between industry and fundamental science
by Johannes Gutleber (CERN) with Alexandra Welsch (UNILIV)

Industry participation - exhibitor stand
Image credit: FCC

A future energy frontier research infrastructure requires current technologies to be pushed far beyond the state-of-the-art. Achieving collider parameters in an affordable and sustainable manner calls for breakthroughs in technologies, such as high-field magnets, superconducting radiofrequency cavities, and efficient RF power sources. This creates unprecedented opportunities for partnerships between academia and industry to the benefit of society.

The FCC study is committed to involving industry partners from the beginning, to jointly define the research and development roadmaps and to launch knowledge transfer programs. Starting collaboration at an early stage creates a mutually beneficial situation. It helps industry carry out strategic planning and provides the research community with better confidence in product quality and enhanced cost control. Nine key players from industry joined FCC Week as sponsors and several more attended the technical sessions, giving a glimpse of both the technical capabilities and economical needs that are required to overcome today’s technical limits.

For example, the R&D program of a 16 Tesla superconducting accelerator magnet, suitable for a 100 TeV hadron collider, calls for focused activities around the improvement of Nb3Sn based low-temperature superconductors in sufficiently large quantities and with ample performance margin, never produced before. Potential suppliers not only face the obvious challenges with respect to an increase of the critical current density and the sustained delivery of large quantities at high quality levels, but also the need to deliver improved materials and quantities at affordable cost for high-energy physics applications, as well as for other solid business cases.

To better understand the opportunities for high field applications in all relevant domains, dedicated technical R&D will be required together with business-case scouting, as foreseen by the EuroCirCol knowledge and innovation management task.

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issue 14

Celebrating the first LHC collisions

Livia Lapadatescu — Fri, 19 Jun 2015 09:08:44 +0000

Celebrating the first LHC collisions

by Alexandra Welsch (UNILIV)

Scenes in the CERN Control Centre (CCC) as stable beams at an energy of 6.5 TeV mark the start of run2 physics at the LHC. Image credit: CERN

On Wednesday, 3^rd June, 10.40 am, the LHC operators declared "stable beams" at 6.5 TeV, the signal for the LHC experiments that they can start taking data for the first time in 27 months, after an almost two year shutdown and an intense eight weeks of beam commissioning. This marks the official start of Run 2 physics at the LHC and the start of a new adventure.

The LHC was filled with 6 bunches each containing around 100 billion protons. This rate will be progressively increased as the run goes on to 2808 bunches per beam, allowing the LHC to produce up to 1 billion collisions per second.

Collisions seen within the ALICE, ATLAS, CMS and LHCb detectors
Image credit: CERN

The world’s most powerful accelerator is now providing collisions at the record energy of 13 TeV, almost double the collision energy of its first run. This new energy frontier will allow researchers to probe new boundaries in our understanding of the fundamental structure of matter.

"For the LHC and its detectors to work, everything has to work. And that means I take my hat off to everyone." says CERN Director-General Rolf Heuer." What comes next will, without a doubt, change the way we see the Universe we live in.”

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Laser and Accelerator Communities Converge in Mallorca

Livia Lapadatescu — Fri, 19 Jun 2015 08:39:00 +0000

Laser and accelerator communities converge in Mallorca
by Magdalena Klimontowska (UNILIV), Rob Ashworth (UNILIV)

Laser and particle accelerator scientists met in the town of Palmanova, Mallorca in March 2015. These two scientific communities were brought together with renowned speakers invited to lead sessions complemented by contributed talks from delegates. In this way, ideas at the forefront of these two fields were shared. This contributed to advancing knowledge towards the development of more functional and cheaper accelerators with ever more diverse applications from health, industrial processes and security through to fundamental research.

The meeting was held by the EU-funded project LA3NET. This large Marie Curie Initial Training Network is coordinated by the University of Liverpool to train 19 early stage researchers at doctorate level in novel projects relating to the application of lasers at accelerators. These researchers are hosted by research centres, universities and industry partners across Europe with additional training provision from other members of the network’s consortium.

Dr. Nathalie Lecesne (GANIL) giving a talk about Ion beam and laser beam diagnostics for laser ion sources. Image credit: LA3NET

The network coordinator Professor Carsten Welsch says: “Europe is investing heavily in world-class research facilities that will offer unprecedented insights into material sciences, nuclear physics and the processes of life itself, but we are not investing in the people we need to exploit these opportunities and already there is a skills shortage.”

The event created an important opportunity for early career researchers to gain from expertise of renowned scientists in the combined fields of laser and accelerators research.

The week was divided into two events with a two-day Beam Diagnostics Workshop followed by a three-day international Conference on Laser Applications at Accelerators.

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issue 14

Towards 90% power conversion efficiency of klystrons

Livia Lapadatescu — Fri, 19 Jun 2015 08:04:45 +0000

Towards 90% power conversion efficiency for klystrons

by Igor Syratchev (CERN)

General view of the 6MW, S-band MBK (40 beams) with PPM focusing with expected RF power production efficiency above 75%. Image credit: JSC ‘VDBT’, Moscow, Russia

Computer simulations confirm that RF production efficiency above 90% can be reached in klystrons with a new electrons bunching technique.

The increase in efficiency of RF power generation for future large accelerators such as CLIC, ILC, ESS, FCC and others is considered a high priority issue. It can contribute to a significant reduction of the investment and operational costs of accelerators. The vast majority of existing commercial high power RF klystrons operate in the electronic efficiency range between 40% and 55%. Only a few klystrons available on the market are capable of operating with 65% efficiency or above.

It is commonly considered the high efficiency klystrons require a low perveance. Limited by technically accessible high voltage levels, this can only be obtained by operating with low currents, thus single beam klystrons are incompatible with the need for high power. The concept of multi-beam klystron (MBK) resolved this inconsistency by introducing many single beams which interact with common RF circuits of the klystron, increasing the power with the multiple beams, whilst preserving low perveance per beam. In the standard klystron optimization procedure the target is to minimize the bunch length prior to it entering the output cavity. Independent studies concluded that in this case the 80% efficiency can be achieved and this value remains as a relatively hard limit.

To reach higher efficiency, the intrinsic limits of the bunching processes and deceleration in the output cavity need to be understood at the level of the electron bunch dynamics.

The new method to increase efficiency is based on the concept of a fully saturated bunch formation using the new bunching technique with bunch core oscillations. The first simulations proved that klystron RF power production efficiency close to 90% can be achieved. The new technology demonstration prototypeis now in fabrication in industry, with expected efficiency above 75% (see image above). The testing of this tube is scheduled for November 2015.

Wake field monitoring to improve FEL performance

Livia Lapadatescu — Fri, 19 Jun 2015 07:17:51 +0000

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.