Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department 9 th Sept’14 1 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Mandate Study the special technologies including conceptual aspects required for the FCC accelerator and identify the possible design and performance limitations for the accelerator. Identify challenges, opportunities for technological breakthroughs and set the R&D program. Understand impacts of technologies Prioritize R&D topics Define scope, schedule, cost guidelines Reporting on Specific Technologies R&D Programs Set up collaborations to address standard FCC issues and R&D opportunities The R&D activities will then be followed in the frame of the Accelerator R&D Work Package which is sub-divided in three Sub- Work Packages: High field Magnet Program Superconducting RF Program Special Technology Program (all except Magnet and RF) 9 th Sept’14 2 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies List of technical systems for FCC-hh, FCC-ee and FCC-he Machine detector interface system needs and conceptual design Superconducting magnet and cryostat requirements and conceptual design Normal magnet requirements and element conceptual design Quench protection and stored energy management requirements and concepts Power converter requirements and conceptual design RF system requirements and conceptual design Proximity cryogenics for superconducting magnets and RF Vacuum system requirements and conceptual design Beam diagnostics requirements and conceptual design Machine protection system requirements and conceptual design Control system requirements Beam transfer elements requirements and conceptual design Dump and stopper requirements and conceptual design Element support, survey and alignment requirements and concepts Collimation systems and absorber requirements and conceptual design Shielding 9 th Sept’14 3 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies European Circular Energy-Frontier Collider Study (EuroCirCol) WP4 Cryogenic Beam Vacuum System Conception Objectives Evaluate the impact of the arc design on technology requirements Develop an overall, integrated design for the cryogenic beam vacuum system consisting of (1) beam-screen, (2) proximity cryogenics, (3) magnet cold bore and (4) vacuum system Determine the needs for advancing individual technologies to meet the requirements Study synchrotron radiation heat load absorption and mitigation of the photo-electrons generation Consider novel mitigation techniques, e.g. based on frequent discrete photon absorbers Description of Work Task 4.1: Work Package Coordination (ALBA) Task 4.2: Study beam-induced vacuum effects (ALBA, CERN) Task 4.3: Mitigate beam-induced vacuum effects (STFC, CERN) Task 4.4: Study vacuum stability at cryogenic temperature (INFN, CERN) Task 4.5: Develop conceptual design for cryogenic beam vacuum system (CERN, CIEMAT) Task 4.6: Measurements on cryogenic beam vacuum system prototype (KIT, INFN, CERN) * Collaboration with KEK Photon Factory for warm of photo-desorption and photo-electron yields of different materials under variable angle of incidence. * similar studies cryogenic temperature being discussed with BINP Novosibirsk. 9 th Sept’14 4 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Beam & Thermal Insulation Vacuum Studies Insulation vacuum tightness Reliability optimisation of multiply bellows for superfluid helium applications Leak tightness is a major issue: hundreds km of welding and thousands of bellows. Welding concepts and testing must be worked out with Laboratories specialised in Materials and Mechanical Engineering. Industrial Partners are also welcomed. Helium pumping by cryosorption. Compensatory measures in case of leaks as an alternative to mechanical pumps. Considering Helium cryosorption onto special materials, possibly cooled by helium gas from the cryogenic return loop. Vacuum modelling using computing tools Molflow code needs to get upgraded for cryogenic beam vacuum simulations Introduce more flexibility and time-dependant bean-induced phenomenon. 9 th Sept’14 5 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Beam Transfer Systems Semiconductor switch designs Silicon carbide technology (MOSFET, IGBT, FHCT) compared to silicon devices, individual switch technologies and stacked performance limits, parallel/series stacking topologies, high reliability design aspects, power triggering, optically triggered devices, radiation resistance for tunnel integration. Kicker magnet designs Impedance shielding, advanced magnetic materials, HV design, magnet segmentation, cooling, transmission line designs. Massless septa Electromagnetic design, mechanical design, radiation resistance, coil design, field quality, stray field. Superconducting septa Electromagnetic design, mechanical design, quench behavior, field quality, stray field, radiation resistance. Massively distributed controls systems Timing and synchronisation, reliability design, redundancy, operability, maintenance aspects. 6 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Beam Instrumentation Beam loss monitors (BLM) for FCC-hh: Use existing technology (LHC) dynamic range, resolution and response time should be fine acquisition system to be developed (later) Development of alternative technologies e.g. “fiber based” BLMs (CLIC development) Emittance measurement for FCC-hh: Study of the limits of synchrotron light measurements (towards X-ray diagnostic?) Study and development of alternative methods (beam Vertex Gas monitors - BGV) Other topics being considered: Beam orbit measurement system (BPM) for FCC-hh (and FCC-ee) Beam intensity monitors (BCT) for FCC-hh (and FCC-ee) Polarimeters for FCC-ee Longitudinal profile measurement for FCC-hh and FCC-ee Luminosity monitors: for FCC-hh (and FCC-ee) Tune measurement for FCC-hh and FCC-ee Chromaticity measurement for FCC-hh Energy measurement for FCC-hh and FCC-ee 9 th Sept’14 7 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Superconducting RF (for ee) RF system requirements are characterized by two regimes. High gradients for H and ̅ – up to ~11 GV. High beam loading with currents of ~1.5 A at the Z pole. RF system must be distributed over the ring to minimize energy excursions (~4.5% energy 175 GeV). Optics errors driven by energy offsets, effect on h. Aiming for SC RF cavities (x570) with gradients of ~20 MV/m. RF frequency, a combination of 200, 400 or 800 MHz (current baseline). Conversion efficiency (wall plug to RF power) is critical. Aiming for 75% or higher  R&D ! (100 MW RF power) 9 th Sept’14 8 Preparation Meeting for the FCC International Collaboration Board J. Wenninger, A. Butterworth, E. Jensen, et al.

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Proximity Cryogenics Proximity cryogenics for RF system for FCC-ee: Study of magnetic refrigeration stage (L. Tavian / CEA Grenoble) at 1.6 K the pressure ratio increases from 40 -> 170 stability with charge variation Proximity cryogenics for magnets for FCC-ee and FCC-hh: Parametric study of LHe distribution (L. Tavian / PHD student) operating temperature (4.5 vs 1.9 K, large cost and power increase) what is the max sector length ? => how many pits/intermediate cryo plants? study of cooling and distribution schemes over 7 – 10km sectors Proximity cryogenics for the beam screen cooling for FCC-hh: Conceptual design of the cooling and distribution schemes (L. Tavian / PHD student) dedicated beam screens operating at around 50K will be needed to cope with the high heat deposition by the beam: up to 44 W/m in the cryogenic system (5MW total) integration of the cooling circuits in a narrow space. compare the performances of Helium and Neon (piping dimensions, efficiency,..) technical challenges related to Neon: “Pipe heaters”, high operating pressures ( bars),.. 9 th Sept’14 9 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Proximity Cryogenics – Interface with WP4 (EuroCirCol) 9 th Sept’14 10 Preparation Meeting for the FCC International Collaboration Board Cryo beam vacuum system

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Proximity Cryogenics – Interface with WP4 (EuroCirCol) 9 th Sept’14 11 Preparation Meeting for the FCC International Collaboration Board Beam-Screen cooling

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Proximity Cryogenics – Interface with WP4 (EuroCirCol) 9 th Sept’14 12 Preparation Meeting for the FCC International Collaboration Board Total cryo power for SR cooling

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Normal conducting magnets  Radiation resistant insulation systems up to 200 MGy – is of interest for nuclear physics machines (e.g. FRIB), fusion (e.g. ITER) Magnets for fast exchange Work out concepts for supports, connections and services, alignment, remotely acted upon and controlled. Similar work is done in nuclear industry, for fusion (JET, ITER), and is of relevance for the LHC maintenance (triplets). Redundant magnet systems to cope with fall-outs during operation, avoiding replacement Introduce additional windings, sections that are “dormant”, but can work reliably, possibly at reduced performance Increase operating margin Compact magnets, decrease costs and footprint, may result in energy efficiency Small aperture, requires high precision and tight tolerances (impact on manufacturing and measurement methods) – this work is relevant to CLIC Alternative yoke materials (Fe-Co) to increase saturation level, reduce the yoke dimensions and weight – this work is relevant to medical applications (TULIP) Air-cooled windings, low current density for reduced energy consumption Are tunable permanent magnet/hybrid magnets an option for storage rings (fixed energy lepton collider) ? 9 th Sept’14 13 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Normal conducting magnets Development of radiation hard easily pluggable normal conducting coils and ancillaries for HL-LHC and FCC Objectives Develop coil insulation materials and schemes for accelerator normal conducting magnets capable of withstanding operational voltages of up to 5 kV after having been exposed to radiation doses of 300 MGy, in presence of humidity and possibly of ozone. Develop fast connectable radiation resistant hydraulic and electrical joints Integrate the above mentioned connection in global solution to enable the construction of “plug-in” magnet units, which would possibly be remotely handled and aligned. Role of participants (very preliminary) Technologies developed here shall be applicable both for dipole and for quadrupole magnets. KEK-JPARC [Kazuhiro Tanaka Integration and alignment BINP [Anatoly Utkin MgO technology, including electrical and hydraulic connections. COCKCROFT [Jim Clarke Electrical and hydraulic connections for impregnated coils To BE DEFINED Impregnated coils (cyanate ester and/or other radiation resistant resin with fiber-glass or mica) FRAUNHOFER Irradiation tests in the BGS facility CERN Coordination 9 th Sept’14 14 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department FCC Special Technologies Quench protection system Quench detection/protection of the main ring (LTS) is a challenge because of Large stored energy density (a factor 3 larger than in LHC) Large operating current density (same as in LHC, at half of the copper fraction) Large circuit inductance (at least 3 times the LHC ?) Quench detection of the LTS magnets/outsert must be on the ms time scale Classical methods, voltage based, requires high noise rejection, fast measurement and decision times Alternative methods would be interesting (optical, magnetic, acoustic, radio-frequency) Quench detection of the HTS insert (very high field option) is so far unresolved Voltage detection based on a threshold possibly too slow/not sufficiently sensitive Develop alternative voltage instrumentation (high sensitivity), and detection method, based on precursors and pattern recognition (catch a quench before it starts) Develop alternative detection principles (optical fibers, magnetic, acoustic, radio- frequency) Quench protection concept to be defined, components to be developed/qualified Diodes and dump, as for the LHC ? Subdivision of the magnet layers ? Large current (in excess of 20 kA) diodes, switches Coupling-Loss Induced Quench (CLIQ) Optimisation of the system, implementation at the design stage of the magnets. 9 th Sept’14 15 Preparation Meeting for the FCC International Collaboration Board

Dr. José Miguel JIMENEZ CERN, Technology Department Dr. Olivier BRUNNER CERN, Beams Department Technical Challenges and Breakthroughs for the FCC-hh Collimation Systems(1/2) Challenges New optics concepts and IR layouts to be developed in order to achieve at least 20x better cleaning with larger collimator gaps Inter-alignment: if the hierarchy of different collimators depend on micrometer or submicrometer alignment from collimator to collimator is necessary, it will be necessary to further develop position measurement and control solutions based on new technologies (piezo, optical, etc…) Operational aspects: how often will we have to change the collimators? Radiation issues? Remote handling? disposable collimators should be developed (quick and fully automated collimator replacement) Breakthroughs New collimator design to withstand much larger energy loads with reasonable transient deformation and no permanent damage. And: Compatible with Impedance and Vacuum requirements Explore new collimation concepts like crystal collimation. Crystal collimation will however push even further the material challenge. 9 th Sept’14 16 Preparation Meeting for the FCC International Collaboration Board