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Linear Collider – Next Steps in R&D. Nan Phinney SLAC. many slides courtesy of G. Geshonke EPS 2009 C. Adolphsen, F. Zimmermann and others. Linear Collider Luminosity. n b : bunches / train N: Particles / bunch A: beam cross section at IP H D : beam-beam enhancement factor. where.
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Linear Collider – Next Steps in R&D Nan Phinney SLAC many slides courtesy of G. Geshonke EPS 2009 C. Adolphsen,F. Zimmermann and others
Linear Collider Luminosity nb : bunches / train N: Particles / bunch A: beam cross section at IP HD: beam-beam enhancement factor where BUT Pbeam = Pwall plug * ηconversion efficiency two-linac length 2L ~ ECM/(Ffilling factor x Ggradient) This points to the critical issues in optimizing the cost of the collider →Efficiency sets the electrical power required for a given beam power →Accelerating gradient sets the length required for a given energy ILC & CLIC take different routes to high efficiency and high gradient 2009 SLUO Meeting Sept 17, 2009
The ILC Reference Design ~31 km N.Walker 2009 SLUO Meeting Sept 17, 2009 200-500 GeV centre-of-mass Luminosity: 2×1034 cm-2s-1 Based on accelerating gradient of 31.5 MV/m(1.3GHz SCRF)
SCRF Technology Required A. Yamamoto 2009 SLUO Meeting Sept 17, 2009
BREAKING NEWS !!!! JLAB press release today announced the first US built cavity to reach ILC specs R. Geng, JLab 2009 SLUO Meeting Sept 17, 2009
SRF Test Facilities DESY KEK, Japan FNAL NML facility Under construction first beam 2010 ILC RF unit test STF (phase I & II) Under constructionfirst beam 2011 ILC RF unit test TTF/FLASH ~1 GeV ILC-like beam ILC RF unit(* lower gradient) A. Yamamoto 2009 SLUO Meeting Sept 17, 2009
New L-Band Station at ESB: Marx Modulator and 10 MW Toshiba Multi-Beam Klystron C. Adolphsen 2009 SLUO Meeting Sept 17, 2009
Sheet Beam Klystron Development Magnetic Shielding Lead Shielding RF cavity Electron Beam Permanent Magnet Cell An elliptical beam is focused in a periodic permanent magnet stack that is interspersed with rf cavities Gun in assembly 2009 SLUO Meeting Sept 17, 2009
Coupler Assembly and Processing Processed in pairs – shipped to FNAL Class 10 Cleanroom @SLAC 2009 SLUO Meeting Sept 17, 2009
RF Distribution Modules with variable tap off Variable tap off allows power adjustment to each cavity 4 2-cavity modules sent to FNAL 2009 SLUO Meeting Sept 17, 2009
RDR Baseline Tunnel Layout Two 4.5 to 5.5 m diameter tunnels spaced by ~7 m. Penetrations (every ~12 m) Accelerator Tunnel Service Tunnel one klystron feeding 26 cavities C. Adolphsen 2009 SLUO Meeting Sept 17, 2009
Klystron Cluster Concept Same as baseline C. Adolphsen 2009 SLUO Meeting Sept 17, 2009 RF power “piped” into accelerator tunnel every 2.5 km Service tunnel eliminated Electrical and cooling systems simplified Concerns: power handling, LLRF control coarseness
ILC R&D plan 14 2009 SLUO Meeting Sept 17, 2009
The CLIC Two Beam Scheme CLIC parameters: Accelerating gradient: 100 MV/m RF frequency: 12 GHz Pulse length 240 ns, 50 Hz active length for 1.5 TeV: 15 km • Two Beam Scheme: • Drive Beam supplies RF power • 12 GHz bunch structure • low energy (2.4 GeV - 240 MeV) • high current (100A) G. Geshonke 2009 SLUO Meeting Sept 17, 2009
CLIC Drive Beam generation Accelerate long bunch train with low bunch rep rate (500 MHz) with low frequency RF (1 GHz) (klystrons) interleave bunches between each other to generate short (280 ns) trains with high bunch rep rate (12 GHz) G. Geshonke 2009 SLUO Meeting Sept 17, 2009 EPS 2009 G.Geschonke, CERN
The full CLIC scheme Not to scale! G. Geshonke 2009 SLUO Meeting Sept 17, 2009
optimum CLIC: 100 MV/m at 12 GHz Optimisation: • Structure limits: • RF breakdown – scaling • RF pulse heating • Beam dynamics: • emittance preservation – wake fields • Luminosity, bunch population, bunch spacing • efficiency – total power • Figure of merit: • Luminosity per linac input power take into account cost model 100 MV/m 12 GHz chosen, previously 150 MV/m, 30 GHz A. Grudiev 2009 SLUO Meeting Sept 17, 2009
CLIC Accelerating Module Drive Beam Main Beam Transfer lines Drive Beam Main Beam G. Riddone 19 2009 SLUO Meeting Sept 17, 2009
CLIC Accelerating structures • Objective: • Withstand 100 MV/m without damage • breakdown rate < 10-7 • Strong damping of HOMs Technologies: Brazed disks - milled quadrants Collaboration: CERN, KEK, SLAC W. Wunsch 2009 SLUO Meeting Sept 17, 2009
Nominal performance of Accelerating Structures Design@CERN, Built/Tested @KEK, SLAC SLAC KEK CLIC target 2009 SLUO Meeting Sept 17, 2009
Power Extraction : PETS Special development for CLIC Travelling wave structures Small R/Q : 2.2 kW/m (accelerating structure: 15-18 kW/m) 100 A beam current 136 MW RF @ 240 ns per PETS (2 accelerating structures) 0.21 m active length total number : 35’703 per linac 8 Sectors damped on-off possibility I. Syratchev Status: CTF3: up to 45 MW peak (3 A beam, recirculation) SLAC: 125 MW @ 266 ns 2009 SLUO Meeting Sept 17, 2009
Power Extraction Structures (PETS) (Previously considered PETS a significant risk) TBTS PETS, 140 ns flat, 25 minutes. PETS 1st run (winter 2008/09) PETS 2nd run (May 2009…) 200 266 ns 133 ns 266 ns 180 160 153 MW (CLIC 0.5 TeV target) 135 MW (CLIC 3 TeV target) Power [MW] 12.05.09 F. Zimmermann 210 Hours 150 Hours 2009 SLUO Meeting Sept 17, 2009
CLIC Test Facility CTF3 Provide answers for CLIC specific issues Write CDR in 2010 Two main missions: • Prove CLIC RF power source scheme: • bunch manipulations, beam stability, • Drive Beam generation • 12 GHz extraction • Demonstration of “relevant” linac sub-unit: • acceleration of test beam Provide RF power for validation of CLIC components: accelerating structures, RF distribution, PETS (Power extraction and Transfer Structure) G. Geshonke 2009 SLUO Meeting Sept 17, 2009
CTF3 building blocks 10 m Infrastructure from LEP PULSE COMPRESSION FREQUENCY MULTIPLICATION magnetic chicane 150 MeV e-linac 30 GHz test stand 3.5 A - 1.4 ms Delay Loop Combiner Ring Photo injector tests, laser CLEX (CLIC Experimental Area) TWO BEAM TEST STAND PROBE BEAM Test Beam Line G. Geshonke 28 A - 140 ns total length about 140 m 2009 SLUO Meeting Sept 17, 2009
Delay Loop Designed and built by INFN Frascati circumference 42 m (140 ns) isochronous optics wiggler to tune path length (9 mm range) 1.5 GHz RF deflector G. Geshonke 2009 SLUO Meeting Sept 17, 2009
Other R&D on performance issues R&D on Damping Rings and Beam Delivery in other test facilities: CESR-TA at Cornell: Electron Cloud mitigation and low emittance tuning ATF/ATF2 at KEK: Low emittance damping ring Final focus test facility to demonstrate nanometer beam sizes and stability 2009 SLUO Meeting Sept 17, 2009
Electron cloud mitigation R&D: PEP-II chicane Mitigation tests in ILC magnetic field M. Pivi Aluminum surface New 4-dipole chicane in the PEP-II LER TiN surface much reduced signal with respect to Al Observed new resonance: Electron current peaks at defined B values (n) Test chamber Al and TiN-coated 2009 SLUO Meeting Sept 17, 2009
ILC Damping Ring R&D Lattice design for baseline positron ring Lattice design for baseline electron ring Demonstrate < 2 pm vertical emittance Characterize single bunch impedance-driven instabilities Characterize electron cloud build-up Develop electron cloud suppression techniques Develop modelling tools for electron cloud instabilities Determine electron cloud instability thresholds Characterize ion effects Specify techniques for suppressing ion effects Develop a fast high-power pulser 11 very high priority R&D items to be addressed for the ILC technical design: Targeted for CesrTA Effort with Low Emittance e+ Beam Targeted for ATF Effort M. Palmer 2009 SLUO Meeting Sept 17, 2009
ATF2 Beamline, January 2008 May 2008 Summer 2007 Model of ILC final focus HA PS ATF2 goals : (A) Small beam size ~37nm (B) nm stability of beam center ATF international collaboration: MOU signed by 20 institutions ATF2 constructed as ILC model, with in-kind contributions Start of beam commissioning: October 2008 FD integration 2009 SLUO Meeting Sept 17, 2009 A. Seryi
ILC – CLIC collaboration 2009 SLUO Meeting Sept 17, 2009
GDE: ILC Timeline 2005 2006 2007 2008 2009 2010 2011 2012 2013 GDE process Reference Design Report (RDR) Tech. Design Phase (TDP) 1 TDP 2 LHC physics Ready for Project Submission We are here B. Barish April 2009 2009 SLUO Meeting Sept 17, 2009
Tentative long-term CLIC scenarioShortest, Success Oriented, Technically Limited Schedule Technology evaluation and Physics assessment based on LHC results for a possible decision on Linear Collider with staged construction starting with the lowest energy required by Physics Conceptual Design Report (CDR) Technical Design Report (TDR) Project approval ? First Beam? G. Geshonke 2009 SLUO Meeting Sept 17, 2009
Summary ILC: 500 GeV, upgradable to 1 TeV Technology quite advanced. Much recent progress. TDP plan to be ready for a proposal in 2013. Key R&D: Cavity gradient, improved RF sources, electron cloud, BDS CLIC: designed to reach 3 TeV, probably in stages Still much R&D. CTF3 just coming on line. TDR expected end 2015. Could be proposed in 2018? Key R&D: Structure gradient & damping, PETS, drive beam generation, also sources, damping rings and BDS issues 2009 SLUO Meeting Sept 17, 2009