Task 2: High-gradient normal-conducting technology development W. Wuensch EUCARD2 rf program review 18 July 2011

Task 2: Overall objectives Advance high-gradient, normal-conducting rf technology through development of: two types of high-gradient CLIC structures - main linac accelerating structures and crab cavities high-power and beam-based X-band test infrastructure. Spread X-band and high gradient expertise to many labs – has been concentrated at CERN/KEK/SLAC

Rapidly spreading X-band and high-gradient technology Linear colliders: CLIC Compact FELs: KVI Groningen, Trieste, Frascati, MaRIE Compton-scattering light sources: MEGARAY Medical accelerators: TERA, X-ray sources Instrumentation: rf based high performance streak cameras

Task 2: Activity structure CLIC main linac accelerating structures with wakefield monitors CEA Manchester PSI X-band crab cavities Lancaster Manchester STFC High-power and beam test infrastructure CEA PSI (Valencia) Overall coordination: CERN

4. CLIC_DDS_A E-field Match-out the full, tapered structure E-field and S11 shown Beam Port11 Port 2 E-field ~198.6mm Matching cell Surface E-Field Axial E-Field 7.5 7 Ez (V/m x104) Es (V/m x104) 5.0 z (mm) 300 z (mm) 225

2. Work in Progress +Future Plans CLIC_DDS_A is equipped with mode launchers –aim is to demonstrate ability to sustain HP CLIC_DDS_B includes full HOM ports Matching the HOM coupler for CLIC_DDS_B (dipole band ~ 15.9 GHz – 18 GHz) I/P at /2=15.9GHz Construct pair of structures with full damping features Moving to a high phase advance (HPA) structure allows other parameters to be optimised 5/6 phase advance structure design in progress In the HPA design further features being explored Additional manifold (8), add SiC? Standard DDS Manifold Additional Manifold Sic EnhancedCoupling Sic 6

Accelerating structures (fabrication in progress) Context of the X-band activities at CEA Saclay CEA entered in the CLIC collaboration with the construction of the Probe Beam Linac CALIFES in CTF3 (in 2005) Exceptional contribution of France to CERN CTF3 contributions: HV modulator and RF components for the CERN klystron test stand and TBL line Accelerating structures for the Two Beam Test Stand Period : 2008 – 2012, Budget = 1 M€ - 48 persons-months (p.m.) HV Modulator Accelerating structures (fabrication in progress) RF Components

Hybrid HEM modes in the cell generated by an offset beam Wakefield monitor development for CLIC accelerating structures Wakefield Monitors = Beam Position Monitors integrated to the accelerating structures Allows beam-based alignment of structures to remove wakefield effects and emittance growth Emittance growth very well improved by aligning the structure to an accuracy of 5 µm GdfidL simulation of TM modes, beam offset dx = 1 mm 18 GHz DX DY Accelerating Structure features : TD24 (CERN design) without RF absorbers 100 MV/m accelerating gradient 24 tapered cells with 2/3 phase advance at 12 GHz with mean aperture of 5.5 mm dipole mode above 16 GHz WFM features : WFM = Two coaxial rf pick-ups on the middle cell damping wg on large side wg for TM-like modes on small side wg TE-like modes Hybrid HEM modes in the cell generated by an offset beam

CLIC Crab Cavity R&D CLIC-CC R&D: LLRF R&D: Multi-cell 11.9942 GHz dipole-mode cavity developed. Various mode damping schemes investigated: Choke Waveguide An optimised 7-cell, waveguide damped design being investigated further. LLRF R&D: CLIC-CC and LHC-CC phase control models under development.

The 12 GHz Power station project at CEA Saclay Independant operation to CTF3 Proximity with chemical lab and clean room Main features: Modulator HT 430 kV Klystron 50 MW – 1.5 µs RF Pulse compressor SLED LLRF with fast phase modulation Specifications : RF Frequency: 12 GHz Peak power: 120 MW Pulse length: 300 ns Repetition rate: 50 Hz Klystron Test structure area RF Pulse compressor Modulator 10

WP tasks Design and fabricate multi-purpose RF Front Ends for WFM. Should be easily adaptable to different frequencies; 15 GHz, 18 GHz, 24 GHz Build hard-ware for CTF3 and SwissFEL injector. Design and fabricate alternative WFM(s) for other structures (collaboration with CERN). 3. Test and commission the different RFFE and pick-ups with beam at CTF3 and SwissFEL injector. Resources: Hardware: 6 RFFE ~ 120 kE; WFM ~ 80 kE. Manpower (PSI): Scientist/engineer 6 months, post-doc 2 years, technician ~ 2 years. + CERN manpower (?) Participating laboratories: CERN, PSI Infra-structures involved: CTF3, SwissFEL Injector

CLIC Crab High Power Distribution Need to understand long term phase stability of the distribution scheme Requires an experiment to measure phase transients. Laser interferometer travelling wave cavity Dual Output or Magic Tee Control 12 GHz Oscillator Main beam outward pick up Waveguide with micron-level adjustment Waveguide with micron-level adjustment LLRF LLRF Phase Shifter From oscillator 12 GHz Pulsed Klystron ( ~ 20 MW ) Pulsed Modulator Vector modulation Control main beam outward pick up

Broad range of participants, many activities Extension of ongoing EUCARD activities Recent expression of interest also by the University of Valencia

CERN request reduced to coordination manpower only Roughly flattens €/lab/activity to 350-400k Activities are stretched, posts are lost, but primary deliverables are maintained

Participation of certain participants in certain activities have been eliminated. Some deliverables are eliminated Need to ask the question whether we are below minimum worthwhile level for further participant-activities.