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FP7 High Luminosity Large Hadron Collider Design Study

Final Report Summary - HILUMI LHC (FP7 High Luminosity Large Hadron Collider Design Study)

Executive Summary:

The Large Hadron Collider (LHC) at CERN is the largest scientific instrument ever designed and built. To keep the LHC at the forefront of research in high-energy physics it will need significant upgrades to increase its luminosity capabilities by a factor of ten after 2020. As part of the High Luminosity LHC (HL-LHC) programme, the FP7 HiLumi LHC Design Study achieved all of its scientific and technical goals within its four years of activity.

This project covered six EU-funded Work Packages with contributions from 15 European laboratories and universities, and partners from United States, Russia and Japan.

The development of technologies key to the HiLumi upgrade such as beam dynamics, magnets, crab cavities, collimators, and superconducting links were the core results of this Design Study. In addition, a timeline and governance for the construction and installation of the HL-LHC was established. The main outcomes of the project are outlined below:

- Networking with the LHC Experiments community to establish a reasonable timeline for the construction and installation of the HL-LHC. This resulted in the creation of the LHC / HL-LHC Plan, which foresees the upgrade installation to begin in 2024.

- A coherent set of beam parameters were established that would achieve the increase of luminosity which is tenfold the design luminosity of the LHC.

- HiLumi contributed to new technologies for the development of the magnets required to help reduce the beam focal length at the collision points. New quadrupole aperture and cooling protocols were defined, and magnets for the insertion regions of the HL-LHC were designed.

- Further technological advances of HiLumi include the development of a new material (molybdenum-graphite) to minimise the impedance of the collimators which act as a barrier between the magnets and the beam. The use of MgB2 wire allowed the development of a novel Superconducting Link system for the HL-LHC. Furthermore, new schemes for beam collision were designed and tested.

- Links with industry were cultivated through outreach events, consultation on best practice, and making European Industry aware of the opportunities for contracts at the level of 500 million euros, to become equipment and service providers during the construction phase. A new H2020 pre-commercial procurement project was launched to incentivize industry regarding the production of very challenging key technologies required for the LHC upgrade. The project brings together international infrastructures with aligned technical requirements in magnet development to act as a single buyer group.

- Beyond industrial influence, the HiLumi LHC Design Study has also had a number of societal impacts. More than 80 outreach talks were given by HiLumi LHC project members, and 35 PhD students and postdocs were involved in research and studies, resulting in six university dissertations based on the project to date. Additionally, some HiLumi LHC technologies have medical applications, which may lead to the production of more compact accelerators for use in medical imaging.

- By upgrading the LHC, Europe will be able to maintain its status as a world-leader in high-energy physics up to at least 2040. This ensures that the European Research Area remains attractive for researchers in a competitive global market.

In achieving all of its technical and scientific goals, the HiLumi design study has paved the way for the transition into the construction phase of the HL-LHC.

Project Context and Objectives:
Thanks to the LHC, Europe has decisively regained world leadership in High Energy Physics (HEP), a key sector of knowledge and technology. The LHC can continue to act as catalyst for a global effort unrivalled by any other branch of science: out of the 10,000 CERN users, more than 7,000 are scientists and engineers using the LHC, half of which are from countries outside the EU.
The LHC will remain the most powerful accelerator in the world for at least the next two decades. Its full exploitation is the highest priority of the European Strategy for particle physics. This strategy has been adopted by the CERN Council, and is a reference point for the Particle Physics Strategy of the USA and, to a certain extent, Japan. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (and thus event rate) by a factor of five beyond its nominal design value. The integrated luminosity goal is a ten-fold increase of the nominal design value. Since LHC is a highly complex and optimized machine, such an upgrade must be carefully studied. The necessary developments requires about 10 years of prototyping, testing and implementing. The novel machine configuration, the High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies representing exceptional technological challenges. These include among others: cutting-edge 11-12 tesla superconducting magnets; very compact with ultra-precise phase control superconducting crab cavities for beam rotation; new technology for beam collimation; and high-power superconducting links with zero energy dissipation.

This FP7 Design Study proposal (HiLumi LHC) was part of an overall project that federated efforts and R&D of a large community towards the ambitious HL-LHC objectives. HiLumi LHC involved 15 European laboratories, as well as participants from outside the European Research Area (ERA), in particular leading US and Japanese laboratories. This participation will be required for the execution of the construction phase as a global project. HiLumi LHC helped foster opportunities for the European industry to bid for contracts worth 300 M€ in innovative fields during the second half of this decade, and established the ERA as a focal point of a global research cooperation and a leader in frontier knowledge and technologies.

The main objective of the HiLumi LHC Design Study was to determine a hardware configuration and a set of beam parameters that would allow the LHC to reach the following targets:
1) A peak luminosity of ×1034 cm-2s-1 with levelling, allowing:
2) An integrated luminosity of 250 fb-1 per year, enabling the goal of 3000 fb-1 twelve years after the upgrade. The luminosity is more than ten times the luminosity reach of the first 10 years of the LHC lifetime.
To achieve this, the HiLumi LHC Design Study included 6 Work Packages.
WP1: Project Management and Technical Coordination
Beyond the management and coordination of all Work Packages (including the WPs not included in the FP7 Program) and the follow-up on the budget and plan, the management team was in charge of installing a HL-LHC Parameter and Layout Committee that served as a common reference for the vast community, canalizing and making the efforts of the other WPs more effective. Major objectives also included the development and endorsement of a strict Quality Assurance (QA) plan for the project; assuring that safety and environmental responsibility were built-in in the design study; assuring the coherence of the project with the LHC Physics Center and the LHC detector and injector upgrade plans. Finally, WP1 was in charge of the dissemination of information and innovation inside and outside the member of the consortium and to industry.
WP2: Accelerator Physics and Performance
Work Package 2 “Optics and Layout” task focused on the preparation of reference lattice and optics files for various configurations that could be used for further beam dynamic studies, the study of the performance limitations in terms of the optics design and the specification of critical magnet parameters for the various scenarios for all linear magnet systems, including the orbit correctors for generating the crossing angle generation and the skew quadrupole correction system. Under its “Particle Simulations” task, the WP aimed at studying the dependence of the Dynamic Aperture of the machine focusing system and the separation-recombination dipole magnets next to the experiments. The objective was to determine the field quality tolerances for the new magnetic elements and specifying tolerances of the correction of circuit settings. The goal of the “Intensity Limitation” task was to define key parameters such as maximum acceptable impedance of the new components and to provide specifications of the impact of electron cloud effects and of the emittance growth rates from intrabeam scattering. The “beam-beam effects” task aimed at evaluating the performance limitations arising from the interaction between two beams with the aim to define key parameters such as minimum required beam separation and maximum acceptable beam brightness values and to identify optimum beam configurations. Last but not least, the “Beam parameter and luminosity optimization” task was focusing on the determination of the optimum choice for the beam parameters based on the experience from the first years of LHC operation.
WP3: Magnet Design
WP3 focused on the analysis of Nb3Sn quadrupoles for the LHC inner triplet and the performance parameters that could be achieved. It aimed at elaborating a conceptual design study of a very large aperture option (150mm), including all requirements for the HL-LHC inner triplet of Nb3Sn quadrupole. The "Separation Dipoles” task was focusing on the conceptual design and prototyping of separation dipoles. A major goal of the “Cooling” task was to choose the operational temperature of the inner triplet and of the separation dipoles, considering and comparing both the superfluid and supercritical He options. The “Special Magnet Studies” task had the objective of designing a two-in-one quadrupole for the outer triplet (Q4-Q6) with nominal beam separation (192mm) and aperture as large as possible (80-100mm), as well as designing a two-in-one quadrupole for the inner triplet was also to be considered. The Nb-Ti option for the inner triplet was also to be considered, taking into account the new targets in luminosity and the follow-up tests of the short model built within the SLHC-PP project. Finally, it aimed at analyse the expect lifetime of resistance quadrupoles in IR1 and IR7, studying possible solutions for the time scale of 2030.
WP4: Crab Cavities
The primary objective of Work Package 4 was to prepare for the construction phase of Compact Crab Cavities, studying the integration of the Crab Cavities in the accelerator tunnels and the preparation of the tunnels for both SPS and LHC. The “Compact Crab Cavity” task was focusing on the conceptual design for each of the proposed compact crab cavities and included the power coupler as the wrong-order-mode couplers. It included the technical design of a 2-cavity cryo-module for a planned proof-of-principle verification in the SPS, including the couplers, tuning system, shielding and ancillary equipment. Prototyping and tests have been included in the Design Study only in the absolute minimum necessary to validate the design choices.
WP5: IR Collimation
Through simulations of beam loss and energy deposition in the experimental IRs, WP5 aimed at assessing locations and magnitudes of beam losses and energy depositions for various upgrades scenarios. It also studied the impact of imperfections on beam loss and explored the interplay between IR beam losses and machine parameters (beta*, crossing angle), specifying operational tolerances related to collimation and IR upgrade. The simulations of energy deposition in the Experimental IRs aimed at further investigating the potentially requirements for shielding. Finally, the “Design of collimation in the Experimental IRs” task was focusing on the required collimation to keep losses at the same level or below before the IR upgrade, with the aim of integrating the collimators in the new layout and optics.
WP6: Cold Powering
Work Package 6 addressed the different cooling options within the LHC cryogenic system, defining the cryogenic interfaces with the other system components, elaborating the optimized flow-scheme and defining cryogenic requirements and components for operation and protection. Its “Electrical transfer and cryostat” task covered the study of the thermal and electrical performance of the multi-circuit superconducting long transfer line, cooled by supercritical helium, both in steady state and in transient conditions. It studied and defined requirements for quench protection of superconducting components and designed a cryostat for the operation of the current leads. Finally, the “Energy deposition and material studies” focused on the maps of energy deposition from collision debris and beam losses and calculated the induced radiation on the cold powering components. It also studied the potential impact on the superconducting components and the consequent requirements for in terms of maximum operating temperature.

Project Results:
In this chapter we summarize the main scientific and technical results. Since this program is a Design Study, we will underline the results that have enabled the passage of the High Luminosity LHC project form the conceptual phase to a phase of prototyping and initial construction
Goals of the HL-LHC
First of all, the main goals of the design study have been all confirmed by the project and by the operation of LHC and by the main results obtained so far. The priority to fully exploit the potential of the LHC has been adopted as first priority among the “High priority large-scale scientific activities” in the new European Strategy for particle physics – Update 2013 , with the following wording: “Europe’s top priority should be the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with a view to collecting ten times more data than in the initial design, by around 2030”.
HiLumi LHC has become the most important project for particle physics in Europe for the next decade. The initial goals defined in the proposal (Section 2.2.) have also been confirmed, namely:
- A peak luminosity of 5×1034 cm-2s-1 with levelling, allowing:
- An integrated luminosity of 250 fb-1 per year with the goal of 3000 fb-1 in about a dozen years after the upgrade. This integrated luminosity is about ten times the expected luminosity reach of the first twelve years of the LHC lifetime.
These goals are based on a solid physics case which is well illustrated in the paper by M. Mangano in the HiLumi Book .
Timeline and scheduling
A key result of the FP7 Design Study has been the networking with the LHC Experiments community to envisage a reasonable timeline and proper scheduling of the project, suitable both in terms of physics and technical and financial feasibility. This has resulted in a new project time line that is illustrated in Figure 1.
Formal approval of the project
Following the Cost and Schedule HL-LHC review in March 2015, the CERN Council approved in September 2015 the financing of HL-LHC in the frame of the MTP (5-year Medium Term Plan) with an integrated long term profile for the HiLumi Project (till 2025). This is summarized in a CERN press release on occasion of the last FP7-HiLumi Meeting at the end of October 2015 .
Project structure and governance
In terms of project structure and governance; the collaboration board and committees set up for FP7 Design Study have proven to be very efficient. In practice the organization scheme and project governance that has been established for the FP7 part have been transposed and extended to the whole project. This organization proved to be very suitable and will continue all along the project construction phase. The PLC, Parameters and Layout Committee, will now be called Technical Coordination committee (unifying the function of PLC and of the Technical Committee): now the parameter and layout is basically frozen and only minor changes can be foreseen. The Steering Committee is now redefined into a Project Management Meeting, while the Coordination Group (making the link with the Experiment Upgrade Projects) will continue all along the project life. The new governance for the construction phase, approved by CERN and by the major stakeholders, has been an important results of the FP7 Design Study and is illustrated in the Figure 2 where it is clear the centrality of HL-LHC in the CERN Accelerator structure.
The work package structure of the HL-LHC upgrade as devised at the beginning of the design study is now complete. The non-FP7 funded WPs have been added directly to the already existing numbering. At the end of the design study, the project enters construction phase with 17 work packages, out of which the 6 FP7 funded ones will be kept as well. The Work Package structure, the technical core of the project is illustrated in Figure 3. The fact that FP7 structure has been retained also for the construction phase and that is open and flexible enough to easily support extensions is to be considered also a very good result of the FP7 program.
Technical management
The FP7 HiLumi study had the ambition to provide management frame for technical coordination equally for the FP7 funded WPs and for the not funded ones as well. This has been very successful, especially in some critical areas for a project which proceeds to the construction phase: Quality Assurance, Safety, industry dissemination. Usually these topics are rarely covered in design phase of a physics oriented projects since they are not directly linked to increase the scientific and technical output of the project. The FP7 HiLumi has put these topics as key element of WP1. On the Quality assurance front the most important results have been:
a) Definition, at an early stage, of the life cycle of the equipment, of their documentation and of the various responsibility, which has been the base of the Preliminary Design Report, a key deliverable for FP7, and the technical base of the Cost & Schedule review;
b) Definition of equivalence among applicable standards, an important tool for a friendly and long-standing collaboration among institutes providing in-kind contributions. To set this frame a 3-day long QA & Standards workshop has been organised in 2014.
In the area of Safety, the priority has been given to radioprotection. Besides carrying out an early study to assess the dose for people intervening on the HiLumi machine the most tangible result is the institution of a new Working Group to merge the experience of Experiment and machine to face the formidable radiation challenges. The working group called ITHACA is now the frame where various innovative technology form remote manipulation to augmented reality are discussed for application in the HL-LHC.
In the area of the Industry outreach two workshops with Industry have greatly contributed to raise awareness of the project in the European industry. With more than 100 participants, they have been a real success and now a portfolio of future orders, classified by typology and size. The portfolio is being organized in collaboration with the Industrial Liaison Industry Officers of all EU Member States with CERN purchasing service. Various participation to national meetings, workshops and industry fairs and exhibitions has also been among the results of the project.
A brief description of the design study and how it is evolving toward the construction phase as well as the complete description, is in the Technical Design Report, which is the most important deliverable of the FP7 HiLumi .
The first important outcome of WP2 is a coherent (coherent internally, with LIU and with LHC operational experience) set of beam parameters in the HL-LHC machine. This has allowed fixing the goals of the companion project LIU (LHC Injector Upgrade), a critical component for CERN injector complex. This set, illustrated in Figure 4 allows meeting the goal of the project of 250 fb-1 per year, which is the key ingredient to reach the final goal of 3000 fb-1 collected in a reasonable time. Actually, the table of Figure 4 is a short form of the beam parameter list and the complete table, which is available at the PLC website:
Together with the beam parameters list, a key results of WP2 is a complete set of optics, with all optics files, that should generate the required beam characteristics. The optics design is complemented by many studies of beam-beam and other collective effective effect like impedance. Both Beam-Beam effects and Impedance evaluation have a strong implication on the hardware.
From the scientific point of view a key outcome of WP2 is the “invention” of the ATS (Achromatic Telescopic Squeeze), a new optics for reaching small beta star (β*), making the maximum profit of the large aperture quadrupoles provided by WP3. It is maybe the jewel of the project, since it is an original idea emerged in the study for the LHC upgrade. It is likely to become a built-in feature in the design of all next generation circular colliders. Figure 5 shows the beta wave generated in the arc (that are used as a giant matching section) and in the collision point.
Another interesting feature, emerged in the Coordination Group and studied in WP2, is the possibility of controlling the pile up density level. This requires a complex beam manipulation making use of crab cavity in crab-kissing mode and of a new SCRF harmonic system. This pile up density control is illustrated by Figure 6 and can increase the quality of thee data collected by the Experiment. With pile up level of 140, four times what has been seen during Run1, spreading uniformly the events over a longer luminous zone can be an asset to avoid data taking degrading in the detector. This feature, called crab-kissing is not in the baseline, since it requires hardware that is not included in the Cost-to-Completion, and in one of the remaining topics of study, in close collaboration with LHC Experiments, for the luminosity upgrade.
A key result of WP2 is the evolution of the robustness of the upgrade vs. variation of various parameters, not considered fixed value like in the table of Figure 4. This has brought to the concept of the enhanced, or ultimate, performance. HL-LHC might have the possibility to generate more collisions, if the Experiments can deal with higher pile up (up to 200 events/crossing) and if more collision time for proton is allowed. The results are summarized in the luminosity profile spanning from LHC starts until HL-LHC end of life in Figure 7. This is an upper limit that could be met (but not guaranteed) in case the hardware behaves as predicted and if there will not be unforeseen beam limitations in the new regimes.
The Inner Triplet quadrupole magnets are - from the hardware point of view - the cornerstone of the High Luminosity LHC project. The upgrade itself is triggered by the necessity to change the present at around 300 fb-1 of integrated luminosity, which gives the opportunity of a long stop (necessary also for the LHC Detectors) and then to install much larger aperture quadrupoles in the low beta luminosity insertion of ATLAS and CMS. The main results of the design study for the quadrupoles are:
a. The definition of the aperture, fixed as early as 2012 at 150 mm, entailing the necessity of using novel Nb3Sn technology. Fixing the aperture so early has allowed making a cascade of study and choices. The design of the quadrupole MQXF could be launched very early and the International Review called to assess the design itself at end of 2014, see , found the design in very good stage, even one year earlier than the end of FP7 design phase. Figure 8 shows the cross section of the MQXF.
b. The definition of the type of cooling. The decision in favour of HEII cooling, while more expensive heavier from the technical infrastructure, has favoured the maximization of the performance. HEII is also the best for heat removal in the coils and heat transport out of the magnet, which are key issues in a high radiation environment like the one of the insertions of HL-LHC. The heat generated at 1.9 K is about three times the one of the present LHC.
c. Use of thick tungsten shield in the inner magnet bore (actually to the beam screen), to limit the radiation heat deposition density in the coil at the same level as the LHC, a few mW/cm3. This reduce to increase in temperature to a few K, an acceptable value for Nb3Sn. In addition the W-shield limits the radiation damage. The dose in the triplet region magnets (IT quadrupoles, correctors and D1 magnet) is the same in HL-LHC at 3000 fb-1 as it is in the LHC at 300 fb-1.
The project MQXF is well advanced and first test of the real magnets (thought short length, 1.5 m) is foreseen beginning of 2016. In Figure 9 the first Nb3Sn is shown during winding (the white colour is due to S2-glass fibre insulation).
Another main result is the design of all magnets of the insertion region. This has required an impressive work, comprising various dipoles and corrector magnets besides the IT quadrupoles. In Figure 10 the cross section of all magnets that need to be manufactured for HL-LHC is shown.
Crab cavity is a new type of Superconducting radiofrequency (SCRF) equipment that is essential to boost the performance of HL-LHC to the desired level. Crab cavities have never been tested on a proton beam. Classical elliptical cavities used in crab-mode have been used for a short time in the Belle electron-positron ring at KEK in Japan. In HL-LHC the novelty is accentuated by the fact that they must be of compact type. Indeed one result of the design study has been to rule out the use of elliptical cavity, in favour of the compact crab cavity. This was a key decision taken very early in the project that has initiated a contractual amendment, allowing WP4 to concentrate all resources on the compact type, thus going beyond the initial scope of the design of a complete cryo-module.
Another critical result of this WP has been the progressive down selection of the various types of compact cavity. Rapidly the WP members agreed to consider three types of cavity, the 4-rods, the RF dipole and the double quarter wave design, see Figure 11. After a thorough campaign of test of the Proof-Of-Principle cavities and with then support of an international review held in BNL, see , the project was able to make a choice in favour of the RFD and of the DQW. Figure 12 shows the test results of the RF dipole the first cavity to be tested. Keeping two designs is the optimal choice since they better suit the different crossing scheme of ATLAS (vertical, RFD) and CMS (horizontal, DQW). Having two designs is consider also a safety measure: in case one of the two would show unexpected shortfalls, the other one can be used as a back-up solution, provided an adaptation of the cryo-module. The 4-Rod type is kept as an option.
Many important results have been obtained in the design study, which cannot be discussed here for brevity but are well documented in the various milestone and deliverable reports of WP4. Here it suffices to mention the big work to understand the field quality of the crab cavity and to reduce their impedance.
As mentioned above thanks to the early decision, the cryo-module concept is already advanced and as shown in Figure 13, we have now a full concept of the entire assembly and the engineering design is well advanced to meet the goal of the test in the SPS in 2018, an important milestone of the HL-LHC project.
In a high intensity machine like LHC, collimators (the ultimate barrier between beam and fragile superconducting magnets) are key equipment for machine protection and for machine availability. In HL-LHC the importance is enhanced by the increase in beam intensity by a factor of two with respect to the LHC and by the five-fold increase of the experiment radiation debris (these last proportional to luminosity). The main results of this WP can be summarized in the following three points:
1. New lay-out of the insertion region collimators, suitable for the 150 mm magnet aperture and beam with brilliance increase by a factor of four (two coming from intensity and another two from emittance). Higher energy density is even more difficult to deal with, since the impact tests in the HiRadMat facility show that very few material and special design are needed to withstand it. Figure 14 shows the new layout in the HiLumi insertion regions (around IP1 and IP2) as defined by FP7 Design Study. A complete new design has been also produced for the betatron cleaning of IR7.
2. The collimators account already now for half of the total beam impedance in the LHC (despite they are less than 50 m long in a 27 km beam pipe!). By doubling the beam intensity, the collimator impedance may degrade the beam quality and even to raise severe instabilities. For these reason WP5 has conducted careful investigation on mew materials, also based on results of previous the FP7-EuCARD programme. Among various options, a solution based on substituting the present graphite collimator with a new composition of molybdenum-graphite (MoGR) coated with a thin Mo layer seems the most promising one. Simulation and beam studies has shown that replacing about ten secondary collimators with new MoGR collimators would reduce the total impedance by a factor two, at least, providing an effective solution to “digest” a double intensity beam.
3. The study has shown the necessity of a new special collimation system in the LHC cold region (Dispersion suppressor), to shield the first dipoles of the continuous cryostat. The study, conducted in conjunction with the 11 T dipole WP (not Hilumi) has produced a full layout based on a collimator at warm temperature laying on a Cold-Warm-Cold bypass in between two 5.5m long 11 T dipoles. These unit of 11 T dipole, bypass and collimator replace an entire 15 m long 8 T LHC dipole. At the moment four such units, see Figure 15, are foreseen for HL-LHC.
The main item of this WP is the design of the superconducting links that are the new element of the HL-LHC magnet cold powering. Indeed, in obedience to the ALARA principle we want to remove the HL-LHC magnet power supplies from the tunnel into a lateral technical gallery that will be excavated for HL-LHC project. This measure helps avoiding people taking up unjustified radiation during machine maintenance. However, this measure also should greatly increase the machine availability since the power and the control electronics will not suffer of single event effects that are unavoidable in the LHC tunnel (unless developing expensive ad hoc rad-hard electronics). These superconducting links started to be developed in FP7-EuCARD. In FP7-HiLumi, because of its lower cost and of the advantage for European Industry, the decision to develop SC link in MgB2 was taken already at the beginning.
The main results of this WP can be summarized as following:
1. Round wire MgB2 has been developed, under CERN guidance and monitoring, by the company Columbus (Genova, I). This is a unique result that did not exist in 2010, paving the way for other Industrial applications (long and high current power transmission cable for electric distribution). Not only the MgB2 has been developed but also deeply characterised in terms of critical current and also in term so magnetization and losses, which is again a very original result, see Figure 16.
2. Design of the integration of the whole system, from Power converter to connection to the magnet bus bar, for Point 7, Point 1 and Point 5. Many technical and scientifically issues have been faced. One of the most interesting challenge were the joints capable of very high current (each link can carry 20 to 100 kA, with single cable of up to 20 kA for the inner triplet) with material resistive element, like the Monel barrier and the nickel matrix used for MgB2 wires. Another item that has been developed and designed is the 20 kA current leads, the end toward the warm end of the Sc links, with new solution illustrated in Figure 17.
3. A further novelty is the new original design of the distribution feedbox, the cryostat that accommodates the current leads and make the transition between cold and warm powering. The solution devised (see Figure 18) is simpler and more elegant than the one of the LHC. It seems also much easier to operate and as such can constitute a new paradigm for future accelerator feedboxes.

Potential Impact:
4.1.1. Impact on technological development capacity of the ERA
HiLumi LHC involved 15 European laboratories, as well as participants from outside the European Research Area (ERA), in particular leading US and Japanese laboratories.
The most important impact of the design study is the preparation of the LHC for the High Luminosity upgrade construction phase.

The LHC High Luminosity Upgrade contributes to the implementation of the new European Strategy for particle physics, of which the top priority is the full exploitation of the LHC. Consequently, the CERN Council confirmed the priority status of the High Luminosity LHC (HL-LHC) project in the CERN scientific and financial programme in 2014, securing funding in CERN’s medium term plan, until 2025.
The importance of the LHC luminosity upgrade for the future of High Energy Physics has been also re-affirmed by the May 2014 recommendation by the Particle Physics Project Prioritization Panel (P5) to the High Energy Physics Advisory Panel (HEPAP), which in turn advises the US Department of Energy (DOE) . The recommendation, a critical step in updating the USA strategy for HEP, states the following: “Recommendation 10: … The LHC upgrades constitute our highest-priority near-term large project.”
In Japan the updated KEK roadmap in 2013 states that “The main agenda at LHC/ATLAS is to continually participate in the experiment and to take a proactive initiative in upgrade programs within the international collaboration at both the accelerator and detector facilities.”
The project delivered a number of important technological impacts, concerning the development of High Energy Physics (HEP) research infrastructures, medical and industrial applications of accelerators, and certain technologies not directly related to accelerators. The potential technological impact is exemplified in the following major areas: Development of superconducting technology for magnets
The target of the project proposal was to 1) finalize a high quality superconducting Nb3SN cable; 2) make it suitable for large current compact cables; 3) trigger industrialization by bringing its cost down.
1) After having overcome many issues including instability, field quality and cabling degradation, thanks to the HiLumi LHC Design Study, Nb3Sn based superconducting cables are now reliably working in collider magnets. The Nb3Sn triplet will be the first accelerator magnet to use a bladder and key mechanical structure. This concept, initially developed at Berkeley Laboratories, allows a more precise control of the mechanics of the high field magnets, and proving its efficiency in a small series can pave the way to extend it to other applications.
2) The project is currently in the process of placing a large order of several million euros of high quality and high current density Nb3SN cable. The current density reaches over Jc=2500 A/m2 at 12T, 4.2K. This is three times beyond the requirements and orders of the ITER project. The Nb3Sn triplet will use a novel protection system based on Coupling-loss Induced Quench (CLIQ). The principle is to uniformly heat the coils in case of quench through the rapid discharge of a capacitor. This concept, developed at CERN, has been proved on short models. In HL-LHC we will have the first application to an accelerator of this system that can also be extended to the protection of solenoids, NMR and MRI magnets.
3) The project also made industrialization possible, e.g. Bruker EAS (a European company based in Germany) is currently using routinely this type of material for their high field NMR magnets.
Development and Industrialization of MgB2 wire
A major breakthrough was achieved for the development and industrialization of the MgB2 wire: the first Powder-in-Tube (PIT) round wire with electrical and mechanical characteristics enabling cabling after reaction was developed in collaboration within CERN and industry (Columbus Superconductors, Italy). A procurement 80 km of wire was launched by CERN at the end of the development program in 2015.
Development of superconducting transmission lines for energy saving
The activity delivered a world record current of 20 kA at 24 K in a 40 m long electrical transmission line made of magnesium diboride (MgB2). This development, performed for the powering of the Hi-Lumi magnets, has been proposed to be used also for innovative transmission lines used for long-distance transport of GW of green power. The test results show that the MgB2 cables can be operated at high currents and at the temperature of liquid hydrogen and that the basic related technology is now proven. This has led first to a collaboration between CERN and the Institute for Advanced Sustainability Studies in Potsdam, and finally to an Industry-led FP7 European project (BEST PATHS), with CERN as a partner, that is very promising for the future of high power transmission cable for electrical industry. The French Transmission System Operator (RTE) is contributing to the BEST PATHS project. The success of the MgB2 and HTS superconducting lines will enable to move the power converters supplying current to the superconducting magnets either to the surface or to radiation free underground areas and to use superconducting transmission lines operated at higher temperatures to connect them. Paving the way to a future increase of LHC energy
The future LHC upgrades critically depend on the success of high field accelerator magnet technology, beyond 10 teslas. Large accelerators can be made more compact with considerable savings in infrastructure and land occupation. The 11 Tesla dipole project aims to replace around 30 8T dipoles in the LHC tunnel with shorter, stronger 11T magnets. Thanks to this project, the space requirement of the magnets decreases significantly, which allows the installation of additional collimators for the HL-LHC upgrade. The first model magnets based on Nb3Sn technology have been already completed and tested. Currently, the full-scale prototypes are being tested. The success of this technology under the umbrella of HiLumi is a significant milestone towards the LHC energy upgrade, which became the FCC (Future Circular Collider) design study, for which 11-13T magnets are essential.
With the 11 Tesla dipole project, the first model magnets based on Nb3Sn technology have been completed and successfully tested. This activity aims to replace some 8T dipoles in the LHC tunnel with shorter, stronger 11T magnets. With this the space requirement decrease significantly, which allow the installation of additional collimators for the HL-LHC upgrade. More compact accelerators for medical and industrial applications
A common requirement for medical and industrial applications is to reduce the volume and weight of accelerators, together with their cost. High field, and therefore more compact, accelerators and gantries could be a real breakthrough making hadron therapy centres smaller and hence more accessible to city hospitals or less wealthy countries. HiLumi contributed to the ongoing development of the first effective and small-sized PET superconducting cyclotron.
Accelerators and MRI (Magnetic Resonance Imaging) have followed parallel development, usually MRI profiting from accelerator technology.
In the same way that the LHC has reached the limit of Nb-Ti technology with its 9 T field magnets, MRI is designing to reach it with the 11.7 T of the solenoid of ISEULT . Within the ISEULT MRI project many companies had been thinking of pushing for beyond 11-12 T. The HiLumi efforts contributed significantly to come to the conclusion that pushing beyond 11.7T is less efficient and therefore efforts are moving towards staying between 9-10T, based on Nb3Sn.
The NbSn technology is also being considered for Gantry (object to deliver beam to patient in hadron therapy) especially in the form of Canted Cos Theta coils.
Recently the use of very high field accelerators is being considered by security agencies and institutions for quick inspection and safety check of baggage and containers; an ultra-compact accelerator can generate penetrating beam to screen the contents of ship containers or allow fast checking of baggage, substituting intruding techniques.
The accurate design and measurement tools and simulation programmes developed for the HiLumi upgrade will also facilitate the design and optimization of accelerators required not only for medical applications but also for high intensity high brightness machines necessary for the production of intense neutron or X-ray beams for the study of the properties of existing and new materials and for the analysis of biological samples. Beam manipulation with Crab cavities
Superconducting RF is the driving technology in the many of the recent and future accelerator projects in the world. Deflecting cavities (aka crab cavities) is increasingly becoming an essential component in future colliders, light sources and Free Electron Lasers for beam manipulation. The development of novel and compact crab cavities reaching very high surface fields in the framework of the HiLumi design study has opened a new paradigm in the field of deflecting cavities and superconducting RF. The immediate benefit for the HL-LHC project is from the gain in physics peak luminosity of more than 70% from the implementation of crab crossing and dramatically increase its efficiency. The realization of these complex structures requires a multitude of new and sophisticated engineering concepts and procedures to fabricate and assemble the cavity and cryo-module components to a precision level much higher than that of the existing structures. The stringent timing requirements at the sub-picosecond level for the operation the crab cavities in the LHC will push the limits of the RF controls beyond the state of the art. Novel materials
In the quest for new materials for future collimators, novel materials with high shock resistance and excellent thermal conductivity are studied. Copper-Diamond and Molybdenum Carbide – Graphite (MoGR) composites are the two most promising examples. The latter is capable to withstand unprecedented thermo-mechanical shock as the ones induced by the HL-LHC beams. This development paves the ground for the design of performing collimators for future accelerators beyond the LHC and is also expected to have an impact on other applications in everyday life: braking systems for high-end automotives and aerospace, thermal management in high power electronics, hot parts for gas turbines and space components requiring extreme geometrical stability are but a few examples of potential applications.
4.1.2. Impact on international cooperation
The HL-LHC project has set new working methods in the area of large particle accelerators. The collaboration (see Figure 19), which involved partners from US laboratories and Japan has gone way beyond the initial design study objectives. The four year concrete collaboration within this Design Study opened the possibility of discussions among partners as to their implication in the construction phase and the choice of a sustainable collaboration model based on a concrete four years of experience. To extend future collaboration for the construction phase, collaboration agreements have been signed between CERN and almost all EU design study partners, including the US and Japanese partners. To extend the collaboration beyond the design study partners, a number of collaboration agreements were signed with universities and research laboratories and discussions are currently underway for further formalized agreements.
This collaboration model is paving the way to global Research Infrastructures in other fields of science.
4.1.3. Impact on European Industry
HiLumi LHC is preparing European industry in an optimal way to bid for industrial contracts, including in high-technology fields, with placing orders of an estimated total value of 500 M€ for the construction phase. A consistent fraction of this value is of high tech equipment. The project already placed orders of a value of 30 M€.
To enhance the co-operation with industry on the production of key technologies that are not yet considered by commercial partners due to their novelty and low production demand, HiLumi triggered the launch of the QUACO project, recently funded by the EU. This project brings together several research infrastructures with similar technical requirements in magnet development to act as a single buyer group. The efforts on the MgB2 wire has led to another EU project, which is an industry-led FP7 project, called BEST PATHS (see Section
Through task 1.6 (Dissemination of Information and Industry Outreach), HiLumi LHC involved Industry at an early stage to the needed development, in order to have industrial feedback about the Best Engineering Practice to be applied, to maximize the chance of technical success of the construction phase.
Through industrial liaison initiatives and Industrial Forums (Superconducting Technologies for Next Generation of Accelerators in 2012, and HiLumi LHC goes to Industry in 2015) the project also aimed to make European Industry aware of the opportunities to become an equipment or service provider in the construction phase. Leading companies in the fields of superconductivity, cryogenics, power electronics, electrical engineering and mechanics were invited to meet the CERN management, several procurement and legal officers and project engineers to explore the technical and commercial challenges emerging from the design and procurement of the LHC upgrade and to match them with the state-of-the-art industrial solutions.
4.1.4. Impact on European science and society
The importance of the LHC luminosity upgrade for European science was acknowledged by ESFRI and also by the P5 Panel of to the High Energy Physics Advisory Panel (HEPAP), which advises the US Department of Energy (DOE). Thanks to this project, Europe has secured to remain in front of science and research up to at least 2040 and will stay an attractive workplace for researchers from all over the world. The key result of the design study is the seamless transition into the HL-LHC construction phase.
More than 80 outreach talks given by project members of HiLumi LHC demonstrated the dynamism of fundamental sciences to the young generation. Via the project’s university partners, HiLumi LHC also involved 35 PhD students and postdocs in high-tech research and implementation. Up to date, 6 university dissertations resulted from the project. (See under publications on CDS).
By means of regular working visits and workshops with partners from the USA, Japan, Russia and other countries, the project emphasised the importance of transnational exchanges of ideas and the mobility of researchers, portraying the excitement and potential of European research for the scientists of tomorrow.
The societal impacts of the HiLumi LHC technologies include medical applications as mentioned above, in addition, very compact PET cyclotrons and enhancements to magnetic resonance imaging (MRI) scans. Technologies resulting from the project also foresee aiding the development of more compact accelerators, which save on cost, space and consumption. In addition the links with industry give the potential for more societal benefits, as spin-offs are discovered and exploited.

The “Dissemination of Information and Industry Outreach” Task 1.6 ensured the effective dissemination of information and innovation inside and outside within the HiLumi LHC consortium and to target audiences by developing and implementing effective communication tools. Target audiences included the broader scientific community, as well as the general public. A specific attention was devoted to outreach to industry.
With the end of EU-funded activities, the High Luminosity LHC project has moved on to the construction phase. Communication activities will continue to be implemented under this new phase, ensuring the visibility of the project’s outcomes and results.
4.2.1. Dissemination tools
The HiLumi LHC website was one of the main communication tools for the project. Since its creation in October 2011, the website has been the entry point not only to the HiLumi LHC Design Study, but to the larger HL-LHC project too. Due to the increased interest in the HL-LHC activities and in the website, in September 2014 the project launched a completely redesigned user-friendly website that was easier to navigate (providing easily accessible information for stakeholders) and that ensured maximum visibility of the project and its results. The website introduced new features to grab visitors’ attention, such as the colourful slideshow.
The website is activity maintained with Work packages highlights, news and event announcements. Project results were collected under the Deliverables and Milestones sections. An Education and Outreach section features educational resources related to the project and to accelerator’s luminosity, including factsheets and explanatory videos. It is to be noted that analysis of the web traffic showed that the average number of visitors per month (1500 ca) exceeded the number of HiLumi members by a factor of 3. After the transition to the construction phase, the HiLumi website will continue to be the main entry point for information on HL-LHC.

Under the Accelerating News newsletter showcases news and results from the biggest accelerator research and development projects, such as HiLumi LHC, EuCARD-2, TIARA, FCC, CERN-EC support to SESAME as well as interesting stories on other accelerator applications. The newsletter also collects upcoming accelerator research conferences and events.
The publication evolved from the EuCARD quarterly project newsletter, which was first published in June 2009 to a subscription list of approximately 200. The first edition of Accelerating News was published in April 2012, with HiLumi LHC being one of the first sponsors. A total of 29 stories from HiLumi were promoted, with highlights from several Work Packages. Over these 3 and a half years, the number of subscribers to Accelerating News rose from 800 to more than 1350 people, attesting to the success of the publication. With the transition to the construction phase, HL-LHC will remain one of the main sponsors of the publication, ensuring continued visibility of the project outputs and results.

Flyers and brochures
A factsheet was created at the beginning of the project to promote the projects at various events, such as conferences, workshops and exhibitions. The factsheet can also be found on the Education and Outreach section of the website.
4.2.2. Dissemination Activities
Publications and reports
All HiLumi LHC publications and reports are available in open access and can be browsed on the HiLumi LHC CDS collection. As of 14 December 2015, the publications logged in the CERN Documentation System (CDS) database amounted to:
papers Peer reviewed Publications Academic Dissertations Books Oral
Presentations Other
Publications Total
148 41 6 1 114 85 398

In addition, HiLumi LHC has produced 43 deliverable reports and 61 milestones reports.
All scientific advances generated by HiLumi LHC have been synthetized in the HiLumi LHC Book “The High Luminosity Large Hadron Collider : the new machine for illuminating the mysteries of Universe”. The book consists of a series of chapters touching on all issues of technology and design, and each chapter can be read independently. The first few chapters give a summary of the whole project, of the physics motivation and of the accelerator challenges. The subsequent chapters cover the novel technologies, the new configurations of LHC and of its injectors as well as the expected operational implications. Altogether, the book brings the reader to the heart of technologies for the leading edge accelerator and gives insights into next generation hadron colliders.
The project scientific and technical results were published in 41 peer-reviewed publications such as:
• Physical Review Special Topics – Accelerators and Beams (APS Physics) – 8 publications
• Physical Review Letters (APS Physics) – 1 publication
• IEEE Transactions on Applied Superconductivity (IEEE) – 32 publications
In addition, 3 publications were submitted to the Open Access database.
HiLumi LHC results were also presented by project members at major international conferences including:
• International Particle Accelerator Conference 2012 (IPAC12) – 21 presentations and/or proceedings
• International Particle Accelerator Conference 2013 (IPAC13) – 36 presentations and/or proceedings
• 16th International Conference on RF Superconductivity (SRF 2013) – 5 presentations and/or proceedings
• 2nd International Beam Instrumentation Conference (IBIC 2013) – 2 presentations and/or proceedings
• International Particle Accelerator Conference 2014 (IPAC14) – 37 presentations and/or proceedings
• International Particle Accelerator Conference 2015 (IPAC15) – 29 presentations and/or proceedings
• 12th European Conference on Applied Superconductivity (EUCAS 2015) – 2 presentations and/or proceedings
A number of HiLumi feature-articles were also published in the CERN Bulletin, CERN Courier, Symmetry newsletter, INFN Newsletter, and in several newspapers.
This large number of publications and oral presentations show the dynamism of project members. The detailed table of the publications and dissemination activities can be found in the Annex. Open access to publications and journals were continuously favoured, and WP leaders were encouraged to open WP owned websites with their key results. In addition, CERN has also bought the rights to make the HiLumi LHC book “The High Luminosity Large Hadron Collider: the new machine for illuminating the mysteries of Universe” an open access publication.
Joint HiLumi-LHC and LARP Annual Meetings
A total of 5 Annual Collaboration meetings were organized in the framework of the project. The meetings gathered on average 160 participants from about 26 institutes and laboratories and from more than 10 countries. The meetings were an opportunity for the HiLumi community to discuss the project scientific and technical achievements. Posters for the Annual Meetings were designed and then distributed to the HiLumi network so that the events could be suitably advertised.
Outreach activities
Outreach to the public has been enhanced with lectures and public talks, mostly by the Project Coordinator. Lucio Rossi has given more than 80 outreach talks with an average audience of 270 people of different ages and various backgrounds, including science festivals, schools and university seminars and colloquia. The country of the talks ranged from the United States to Japan, Italy, Germany and France. At the end of each talk, an open discussion with the public opened the floor to questions and debates. The list of events is available at Some talks had an audience that exceeded 2000 people. The Project Coordinator was also featured several articles in public newspapers, e.g. Liberta, Corriere della Sera, etc, as well as in scientific magazines and newsletters.
A general presentation has been also prepared by the Project Coordinator to ease the work of the project member when giving an outreach talk on the scopes of the HL-LHC project. The presentations are available in English, German and Italian from the public website .
The year 2015 was proclaimed the International Year of Light and light-based technologies. CERN took this opportunity to launch a communication campaign about the High Luminosity LHC project, which included special events throughout 2015. HiLumi LHC was also contributed to the popular Light2015 UNESCO blog. The HiLumi LHC contribution will also be included in a booklet produced be the International Year of Light on the topic. The booklet will be published by February 2016. Outreach to industry has been a major component of HiLumi LHC communication efforts. Liaison with industry was coordinated by an Industry and Technology Board, which aimed at preparing the participation of European Industry in the HL-LHC construction. A total of two workshops and one Industry Forum were organized to connect companies with research infrastructures, providing them with updated information on the technical and technological challenges of HL-LHC and gathering efforts to face the commercial challenges emerging from the design and procurement of the LHC upgrade. Overall, more than 400 participants took part in the events.

List of Websites:
For all communication contact Project Coordinator: Lucio Rossi (