CERN Accelerating science

Ensuring safer operation at higher luminosities

The TDI (Target Dump Injection) is a beam-intercepting device installed on the two injection lines of the LHC (Large Hadron Collider) to protect the superconducting elements of the machine during injection in case of a malfunction of the injection kickers.

Due to the higher bunch intensities and smaller beam emittances expected in the HiLumi-LHC phase, and following the operational experiences of the TDI, a complete revision of the design has been performed. The result of this reengineering work is the TDIS (Target Dump Injection Segmented),a key element for the safe operation of LHC at high luminosity.   

The major changes that can improve the reliability of this component are:  

  • A more efficient cooling circuit better integrated in the jaw, in order to dissipate the beam induced Radio Frequency (RF) heating.
  • A more robust and reliable motorization system and fixation points to contain and guide any possible deformation.
  • A new geometry with smaller cavities, better contacts and RF fingers to damp as much as possible the HOM.

Several other aspects were taken in consideration while reengineering the TDIS and as the letter “s” indicates, the new design is segmented! The new modular design will simplify the assembly procedure, the installation, the maintenance and will improve the robustness, setup accuracy and operational reliability of the system.

The new injection dump consists of three modules, independently movable, of equal length (each ~1.6 m long) hosting different absorber materials: two modules with low-Z absorbers blocks (graphite R4550) and one with a sandwich of higher-Z materials (Ti6Al4V and CuCr1Zr). A careful choice of the material ensures that no damage occurs in the machine as well as that the TDIS will cope with all direct beam impact conditions. Impedance, e-cloud and radiological aspects were also taken into account in the final design.

After several years of engineering and specification work, the efforts now move to the procurement of materials and components for the assembly of the TDIS prototype. As of today, most of the components required to build-up one TDIS prototype (plus one module for validation purposes at CERN’s HiRadMat testing facilities) are in the manufacturing phase, although some key elements have already been produced. Amongst them, the absorbing blocks and one back-stiffener of a jaw to be installed in the HiRadMat module. This stiffener is a structural component intended to ensure the requested flatness of the jaw’s surface exposed to the beam and is produced out of TZM (Molybdenum alloy) in order to withstand the high thermomechanical loads induced in case of beam impact.

3D view of the HiRadMat module that will be assembled in 2018 along with a full TDIS prototype (Image credit: Luca Gentini). 

Finally, it should be noted that the aforementioned manufactured parts are currently going through the qualification process at CERN. Ultrasonic inspection and metrology analysis are so far completed and the next stage is vacuum testing to confirm the compatibility of the graphite blocks and the TZM back-stiffener with an ultra-high vacuum environment.

The start date for the assembly process of the prototype and the HiRadMat module is planned for early June, right after the arrival of the vacuum vessels.

Outi Heloma (CERN), Isabel Bejar Alonso (CERN)
Education for innovation in Hilumi and FCC
6 Mar 2018

Education for innovation in Hilumi and FCC

What’s in it for innovators in Hilumi and FCC? Twenty young researchers interested in innovation and entrepreneurship participated in this two-day course.

Panagiotis Charitos (CERN)
Taking accelerators on board: Exploring unchartered waters with ARIES
11 Dec 2017

Taking accelerators on board: Exploring unchartered waters with ARIES

ARIES-Industry event brings together experts on accelerator applications for ship exhaust gas treatment.

Panagiotis Charitos (CERN)
Science transcends boundaries
8 Dec 2017

Science transcends boundaries

European and Japanese collaboration in the framework of the FCC study was highlighted during Science Agora 2017

A new step towards successful MgB2 superconducting coils

On 7th March the INFN-LASA laboratory completed the construction and successfully tested a superconducting coil in MgB2 (Magnesium di-Boride based conductor) to be used in a high order corrector magnet. Development of MgB2 coils for a Round Coil Superferric Magnet corrector was launched in the framework of the HL-LHC project IR magnets. This design, proposed in the 70s by Russian scientists, allows to create any multipole with the same round coil through a three dimensional shaping of the iron; the low curvature radius of the coil allows using MgB2 superconductor. 

Application of this design to the HL-LHC high order correctors started in 2014 by our late lamented Giovanni Volpini with CERN support. Computations showed that this option had a lower efficiency in terms of longitudinal space, and therefore the classical superferric option with Nb-Ti and standard two dimensional iron shaping was retained; INFN-LASA built three correctors based on this design in the past two years, and two more types are being built in collaboration with industry. Nonetheless, the MgB2 RCSM prototype magnet has remained in the development line to explore the manufacturing aspects of this design, and to have a MgB2 corrector available for high energy accelerators, a prima for this technology.

A single coil, wound with conductor produced by Columbus Superconductors (Genova), was tested in LASA without the iron yoke; this coil is the active part of the RCSM magnet, which will be assembled and tested in September 2019. The coil, cooled at 4.2 K with liquid helium, reached without any training quench the specification current (“ultimate current”, 160 A), passing also the stability test of one hour at the ultimate current. The coil was then energized to larger currents to investigate the limiting current, which resulted in 243 A; this is 73% of the intersection of the load line with the critical current for virgin, not-degraded, conductor. It should be noted that this current limit was reached without intermediate quench (no training).


Image Credit: INFN/LASA

“The test result is beyond our expectations,” says Massimo Sorbi from INFN-LASA. “MgB2 virgin conductors are very prone to degradation when they are wound and manipulated with even better procedures used for the other common superconductor magnets based on NbTi. Our cryogenic test was also complemented with the measurement of the thermal contraction of coil (literature is lacking of this data regarding MgB2 coils), which will enable a better design of the mechanical structure for the final magnet.” “This is a relevant technological spin-off of the HL LHC project”, says Ezio Todesco, in charge of HL-LHC IR magnets, “enabled by the synergy between INFN-LASA and CERN”.


Image Credit: INFN/LASA

Athena Papageorgiou Koufidou & Fiona J. Harden (CERN)
HiRadMat: testing materials under high radiation
7 Dec 2017

HiRadMat: testing materials under high radiation

The CERN test facility offers high irradiation testing to researchers.

Alessandro Bertarelli (CERN)
Workshop for extreme thermal management materials
8 Dec 2017

Workshop for extreme thermal management materials

Researchers gathered in Turin, Italy to discuss current and future work.

Marco Zanetti (INFN & Univ. Padua), Frank Zimmermann (CERN)
Workshop shines Light on Photon-Beam Interactions
7 Dec 2017

Workshop shines Light on Photon-Beam Interactions

The ARIES Photon Beams 2017 Workshop was held in Padua, Italy in late November 2017.

From first concept to the SPS: the challenge of the HL-LHC crab cavities cryomodules

The first concepts of the HL-LHC crab cavities started more than 10 years ago. They were the fruit of the discussions of a young physicist at BNL and a beam dynamics expert at CERN. The concept was not new but using it for the LHC implied a long journey of technological challenges.

The distance between the LHC beams required a new RF concept for particle deflection with a novel shapes and significantly smaller in size than conventional RF cavities. The challenge was taken with enthusiasm by the RF community resulting no less than 10 concurrent designs from RF experts across three continents. In 2013, three designs were considered to be the most adapted to the LHC and became ready for the development of a proof of principle. While this may sounds like a moment of fierce competition, in reality it showed the spirit of cooperation towards a common goal among the members of our community. The results of the RF tests of the Double Quarter Wave (DQW), the RF Dipole (RFD), and the four Rod (4R) were highly promising and analysed by an international panel in 2014 that recommended to focus the efforts on the first two designs to make a full validation of the cryomodule in the CERN’s SPS.

One of the crab cavities that will be used in the HL-LHC (Image Credit: CERN)

The entire community concentrated on the two designs and on the development of the concept of all the other required components of the cryomodule that should host the cavities. The effort that had already started in 2013 by CERN required the knowledge, experience and imagination of the collaboration.

In fact, 2015 became a decisive year that started with a collaborative design thinking of the most innovative components. Among them we can highlight the frequency tuning system, the helium tank and the RF lines, all of which required inspiration beyond the conventional wisdom to adhere to the strict needs of HL-LHC. There is a global consensus on the fond memories of the design phase in 2015, wild enthusiasm and collaboration. Effectively, during this extremely critical period every team contributed to the design before concentrating on the detail development of the different components. The result was as harmonic as the sound of a good symphonic orchestra. A robust design that was flexible to be used for the test of the cryomodule at the SPS, easily adaptable for the LHC and that could be transferred to the industry for the series production.

Today the first cryomodule is finished and under cold test without any delay on the manufacturing plan that was prepared more than two years ago. A plan that at that moment was considered almost impossible. Today, the infrastructure in the SPS is ready and just waiting for the cryomodule installation. The hard work of these last 5 years of engineers and physicists from US, UK and CERN will reap the benefits of their hard efforts.

In the meantime, the team is thinking about the future. In December the industrial contract for the series production of the cavities under CERN’s responsibility will be adjudicated. The global collaboration will be further enlarged with discussions with laboratories in Canada and in Japan willing to contribute to the construction of the cryomodule.

A global effort and we hope a global success!

Ubaldo Iriso (ALBA-CELLS)
Different techniques of emittance measurements for SLS and FELs
2 Mar 2018

Different techniques of emittance measurements for SLS and FELs

The status of different techniques and some new approaches of emittance measurements for SLS and FELs were analyzed in a topical workshop at ALBA.

Isabel Bejar Alonso (CERN) , Panagiotis Charitos (CERN)
A bright future for HL-LHC
7 Dec 2017

A bright future for HL-LHC

The 7th HL-LHC annual collaboration meeting in Madrid reviewed the current progress and set the goals for next year.

Chris Edmonds (University of Liverpool)
Tactile Collider
13 Mar 2018

Tactile Collider

Sensory exploration of LHC science for children with visual impairment

A bright future for HL-LHC

The 7th HL-LHC Annual meeting in Madrid took place in November. An intensive week to review the progress done during 2017 and the objectives for 2018. The HL-LHC project is moving to construction phase. The hardware models as well as the prototypes of the equipment in their final configuration are under construction or currently tested. 

In 2017, the HL-LHC project achieved a number of key milestones. The first crab cavity prototypes built in the US were successfully tested by LARP collaboration that is transforming into US-HL-LHC AUP (Accelerator Upgrade Programme) and the full cryomodule containing the crab cavities built at CERN was successfully tested at 2K; just in time to be integrated in the SPS during the winter where their performance will be studied next year by using a beam from the SPS.

The first low impedance collimators were tested and characterized in the LHC machine together with the crystal collimation concept (not in HL-LHC baseline). The test of the first long prototype of the MQXF quadrupole, manufactured by US-LARP-AUP for the new low-b HL-LHC insertions has just started in BNL. The first results are expected in February. Moreover, the construction of the first 11 T magnet and DS collimator and the test of the first long SC link, all manufactured at CERN, were among the highlights of the HL-LHC week.

In addition, the successful implementation of the ATS optics (devised for the LHC upgrade) and the tests of the full detuning operation mode of the LHC RF system during the LHC operations: are two key ingredients that increased the performance of the LHC in 2017 and pave the way for its high-luminosity upgrade.

This year we had an international review that validated technically the e-lenses and equipment that could be part of the HL-LHC baseline. Finally, we have concluded on the interface between the machine and the experiments. These above developments in all these different fields show how the HL-LHC project is making progress towards final implementation.

There are several other relevant milestones achieved by the HL-LHC collaborations. The short model of the D1 reached ultimate current in KEK. The first octupole and decapole prototypes also went beyond the ultimate current in INFN LASA. The D2 model construction in the industry is well advance, a collaboration led by INFN. Finally the short mechanical model of the nested orbit corrector and the first coil were also accomplished this year in CIEMAT

Procurement for HL-LHC

2017 was also the year for the preparation and adjudication of some of the bigger contracts of HL-LHC. The tender for civil engineering works for Point 1 and Point 5 (including large excavation and construction work) was announced in July and is presently under final evaluation. The contract adjudication will be done in March and the first civil works for HL-LHC are expected to start in summer 2018.

This year has also seen the first tender for the collimators that will be installed during the next Long shutdown 2 (LS2). The adjudication in December will ensure their delivery on time for their installation before mid-2020. In parallel to the construction of the crab cavities cryomodule to be tested in the SPS in 2019, the tendering of the Jacketed Crab Cavities DQW type has been placed. The contract will be adjudicated this December and will be complemented by the work done by AUP on the RFD type crab cavities. Also in the field of the 11T magnets, HL-LHC adjudicated the tender for the construction on CERN site of the coils for the 11T dipole. An industrial service contract where skilled employees will use the facilities built at CERN and that were used to build the first models and prototypes of the 11T dipole.

The next challenge for HL-LHC is to ensure a coherent integration lay-out that will meet the constraints imposed by the lay-out of the civil engineering and the preparation of a first version of the installation plan. Meanwhile, the optimization of the design and construction of the components is in progress. “As the window to keep various options in the planning narrows we need to work hard to make final choices for the implementation of an industrial construction roadmap” says Lucio Rossi HL-LHC Project Leader.  

The second HL-LHC Collaboration Board also took place during the HL-LHC week. HL-LHC steadily becomes a global project. 18 HL-LHC Collaboration Board members and 11 collaboration partners with R&D contributions work together with CERN to make possible HL-LHC. The gathering in Madrid showed the interest of the community on the development of the HL-LHC technologies with multiple proposals for in-kind contributions.

To learn more about the HL-LHC Project read the Technical Design Report (TDR) https://e-publishing.cern.ch/index.php/CYRM/issue/view/40 and or brand new website .

 

*AUP HL-LHC Accelerator Upgrade Project (BNL, FNAL, LBNL and SLAC)

Panos Charitos (CERN)
Charting impact pathways of Research Infrastructures
13 Mar 2018

Charting impact pathways of Research Infrastructures

Kick-off meeting of the H2020 “RI-PATHS” project in Brussels.

Isabel Bejar Alonso (CERN) , Rama Calaga (CERN), Ofelia Capatina (CERN)
From first concept to the SPS: the challenge of the HL-LHC crab cavities cryomodules
13 Dec 2017

From first concept to the SPS: the challenge of the HL-LHC crab cavities cryomodules

Crab cavities will help increase the luminosity of collisions in the High-Luminosity upgrade of the LHC.

Isabel Bejar Alonso (CERN) , Panagiotis Charitos (CERN)
A bright future for HL-LHC
7 Dec 2017

A bright future for HL-LHC

The 7th HL-LHC annual collaboration meeting in Madrid reviewed the current progress and set the goals for next year.