Status of Accelerator R&D at ILC 2013 년 8 월 12 일 경북대김은산 1
The Beginning an idea A Possible Apparatus for Electron-Clashing Experiments (*). M. Tigner Laboratory of Nuclear Studies. Cornell University - Ithaca, N.Y. While the storage ring concept for providing clashingbeam experiments ( 1 ) is very elegant in concept it seems worth-while at the present juncture to investigate other methods which, while less elegant and superficially more complex may prove more tractable. M. Tigner, Nuovo Cimento 37 (1965) 1228 2
Two Linacs, No Bends! e + e - ~15-20 km For a E cm = 1 TeV machine: Effective gradient G = 500 GV / 15 km = 34 MV/m real-estate gradient Cost scaling: storage ring $ tot E 2 linear collider $ tot E 3
Requirements from Physics Basic requirements: Experiments Luminosity : Ldt = 500 fb -1 in 4 years E cm : 200 500 GeV and the ability to scan E stability and precision: < 0.1% Electron polarization: > 80% Extension capability: Energy upgrade: 500 1,000 GeV 5GeV e-, e+ Damping Ring (3.2km) E+ production Bunch compression e- ML E+ ML Bunch compression IP E- production 4
ILC layout not too scale - injectors (sources and damping rings) - final focus system and interaction region 5
Central Region Central Region 5.6 km region around IR Systems: electron source positron source beam delivery system RTML (return line) IR (detector hall) damping rings Complex and crowded area common tunnel Damping Rings detector RTML return line e+ source e+ main beam dump e- BDS muon shild e- BDS 6
LC Parameters Linear Collider Design Issues L Luminosity: Effectiveness of collider N particles in a bunch n b bunches in a machine pulse f Energy Reach rep pulses per second σ x,y x (and Ey) beam = 2b sigma Lat IP G H CM fill linac RF D disruption of one beam caused by the fields of the other E CM collision Center of Mass Energy Luminosity b_ fill the fraction L = n of the b N 2 machine length f actually used for acceleration rep L_ 4ps s H * D linac the length of the linac x* y G_ RF the average accelerating gradient 7
500 GeV Parameters Physics Beam (interaction point) Beam (time structure) Max. E cm 500 GeV Luminosity 1.8 10 34 cm -2 s -1 Polarisation (e-/e+) 80% / 30% d BS 4.5% s x / s y 574 nm / 6 nm s z 300 mm ge x / ge y 10 mm / 35 nm b x / b y 11 mm / 0.48 mm bunch charge 2 10 10 Number of bunches / pulse 1312 Bunch spacing 554 ns Pulse current 5.8 ma Beam pulse length 727 ms Pulse repetition rate 5 Hz Accelerator (general) Average beam power Total AC power (linacs AC power 10.5 MW (total) 163 MW 107 MW) 8
ILC in a Nutshell 200-500 GeV E cm e + e - collider L ~2 10 34 cm -2 s -1 upgrade: ~1 TeV central region SCRF Technology 1.3GHz SCRF with 31.5 MV/m 17,000 cavities 1,700 cryomodules 2 11 km linacs Developed as a truly global collaboration Global Design Effort GDE ~130 institutes http://www.linearcollider.org/ilc 9
25 year long effort towards a very high performance e+ / e- collider Year 1987 1992 1998 2004 2006 2012 Phase SLC @ SLAC LC Design Global Design Effort - ILC 500 GeV Linear Collider R & D 8 schemes 4 2 Comparative Reviews Beam Test Facilities - Linac (cost-driver) Beam Test Facilities - Emittance (SLAC) Technolog y Review 1995 Technology Review 2002 International Technology Review Panel 2004 NLCTA, TTF / FLASH FFTB ATF CesrTA ATF2 General issues ILC/CLIC NML, STF, CTF
Reference Design - 2007
Technical Design Report Completed TDR Part I: R&D ~250 pages Deliverable 2 ILC Technical Progress Report ( interim report ) AD&I TDR Part II: Baseline Reference Report ~300 pages Deliverables 1,3 and 4 Reference Design Report Technical Design Report * end of 2012 formal publication early 2013 12
RDR (2007) to TDR (2012) Cost Containment Effort Single acc. Tunnel Reducing # bunches w/ smaller damping rings Allowing gradient spread 31.5 MV/m +/- 20 %, Site-dependent RF system: Clustered on surface (KCS), Distributed in tunnel (DKS) RDR 07 (Reference Design Rep.) TDR 12 (Technical Design Rep.) 5 m Flat-land or Mountainous Tunnel Design 13
Major R&D Efforts in TD Phase SCRF technology and beam acceleration: Cavity Gradient required:31.5 MV/m ILC SCRF cavity R&D Effort for ~ 7 x Gradient (KEK-TRISTAN, CERN-LEP) Gradient Progress : < 37 MV/m> (Record:46 MV/m at DESY) System engineering: S1-Global program with global effort Industrialization of cavity production Electron Cloud Mitigation (CESR-TA) Nano-beam handling : ILC requires a beam size ~ 6 nm (vertical) and stability ~2nm: Progress in KEK-ATF2: achieved ~70 nm (at 1.3 GeV), corresponding to 10 nm (at 250 GeV, ILC) 14
Global Plan for SCRF R&D Year 07 2008 2009 2010 2011 2012 Phase TDP-1 TDP-2 Cavity Gradient in vert test to reach 35 MV/m Yield 50% Yield 90% Cavity-string to reach 31.5 MV/m, with onecryomodule System Test with beam acceleration Preparation for Industrialization Communication with industry: Global effort for string assembly and test (DESY, FNAL, INFN, KEK) FLASH (DESY), NML/ASTA (FNAL) QB, STF2 (KEK) 1 st Visit Vendors (2009), Organize Workshop (2010) Production Technology R&D 2 nd visit and communication, Organize 2 nd workshop (2011) 3 rd communication and study contracted with selected vendors (2011-2012) 15 15
1.3 GHz Superconducting RF Cavity solid niobium standing wave 9 cells operated at 2K (LHe) 35 MV/m Q 0 10 10 16
Road to High Performance Electropolishing High-Pressure Rinse (HPR) 800 C annealing and 120 C baking 17
Worldwide gradient R&D Exceeds 2005 GDE R&D goal ILC accelerating gradient spec: 31.5 MV/m ±20% GDE global database Asia KEK; Europe DESY; US JLab, FNAL, ANL Qualified cavity vendors Asia 2; Europe 2; US 1 18
Cryomodule construction 19
Worldwide Cryomodule Development CM1 at FNAL NML module test facility S1 Global at KEK SRF Test Facility (STF) PXFEL 1 installed at FLASH, DESY, Hamburg 20
RF Power Source and Distribution Marx modulator 10MW MB Klystron Adjustable local power distribution system ILC Accelerator 21 Nan Phinney, 6/12/13
shield wall removed 22
European XFEL @ DESY Largest deployment of this technology to date - 100 cryomodules - 800 cavities - 17.5 GeV The ultimate integrated systems test for ILC. Commissioning with beam 2 nd half 2015 23
Damping Rings Circumference 3.2 km Energy 5 GeV RF frequency 650 MHz Beam current 390 ma Store time 200 (100) ms Trans. damping time 24 (13) ms Extracted emittance x 5.5 mm (normalised) y 20 nm No. cavities 10 (12) Total voltage 14 (22) MV RF power / coupler 176 (272) kw Positron ring (upgrade) Electron ring (baseline) Positron ring (baseline) No.wiggler magnets 54 Total length wiggler 113 m Wiggler field 1.5 (2.2) T Beam power 1.76 (2.38) MW Values in () are for 10-Hz mode Arc quadrupole section Dipole section Many similarities to modern 3 rd -generation light sources 24
Critical R&D: Electron Cloud Extensive R&D programme at CESR, Cornell (CesrTA) Instrumentation of wiggler, dipole and quad vacuum chambers for e- cloud measurements RFA low emittance lattice 25
Positron Source (central region) to Damping Ring not to scale! 150-250 GeV e- beam aux. source (500 MeV) Photon collimator (pol. upgrade) Target Flux concentrator Pre-accelerator (125-400 MeV) SCRF booster (0.4-5 GeV) Energy comp. RF spin rotation solenoid SC helical undulator located at exit of electron Main Linac 147m SC helical undulator driven by primary electron beam (150-250 GeV) produces ~30 MeV photons Capture RF (125 MeV) converted in thin target into e+e- pairs e- dump photon dump 150-250 GeV e- beam to BDS yield = 1.5 polarisation yield e+/e- 26
Beam Delivery System and MDI Geometry ready for TeV upgrade e+ source e- BDS electron Beam Delivery System 27
TTF/FLASH (DESY) ~1 GeV ILC-like beam ILC RF unit (* lower gradient) Global Cooperation for ILC Accelerator Beam Demonstration STF (KEK) operation/construction ILC Cryomodule test: S1-Global Quantum Beam experiment DESY INFN Frascati KEK, Japan FNAL CesrTA (Cornell) electron cloud low emittance Cornell DAf NE (INFN Frascati) kicker development electron cloud ILC Accelerator ATF & ATF2 (KEK) ultra-low emittance Final Focus optics KEKB electron-cloud NML facility ILC RF unit test Under construction Nan Phinney, 6/12/13
50 m ATF2 Final Focus R&D: ATF2 @ KEK The ATF2 has been designed, constructed and operated under the international collaboration. Focal Point (ATF2-IP) y~37nm Final Focus (FF) System Extraction beamline Damping Ring y~10pm ATF2 LINAC DR 120 m Formal international collaboration ATF2 Technical Review, April3-4, 2013, KEK 4 29
KEK-ATF:Progress Ultra-small beam Low emittance : KEK-ATF Achieved the ILC goal (2004). Small vertical beam size : KEK ATF2 Goal = 37 nm, 160 nm (spring, 2012) ~70 nm (Dec. 2012) at low beam current 30
Final Focus R&D: ATF2 @ KEK Test bed for ILC final focus optics - strong focusing and tuning (37 nm) - beam-based alignment - stabilisation and vibration (fast feedback) - instrumentation IP beam size monitor 31
Luminosity Upgrade Concept: increase n b from 1312 2625 Reduce linac bunch spacing 554 ns 336 ns Doubles beam power 2 L = 3.6 10 34 cm -2 s -1 AC power: 161 MW 204 MW (est.) shorter fill time and longer beam pulse results in higher RF-beam efficiency (44% 61%) 32
Luminosity Upgrade Adding klystrons (and modulators) Luminosity Baseline upgrade 39 26 cavity RF unit K K Damping Ring: Luminosity upgrade 26 cavity RF unit K K Positron ring (upgrade) Electron ring (baseline) Positron ring (baseline) Arc quadrupole section Dipole section 33
TDR Value Estimate By accelerator system BDS 4% IR 2% Common 7% Electron Source 3% Positron Source 4% Damping Rings 6% RTML 8% Controls and Compu ng Infrastructrure 6% Instrumenta on 1% Dumps and Collimators 1% Vacuum 1% Non L-band RF 1% Area system specific 1% Main Linac 66% Magnets and Power Supplies 6% Installa on 1% Cryogenics 8% CFS-Civil construc on 18% CFS-other 11% CFS-Civil construction 10% CFS-other 6% L-band Cavities and Cryomodules 32% L-band HLRF 9% Cryogenics 7% Controls 2% TOTAL Main Linac 66% L-band HLRF 10% L-band Cavi es and Cryomodules 35% By technical system 34
Unsung Heroes Not high-tech But equally important and challenging And 30% of the total project cost! 35
Japan Interests in Hosting ILC Kitakami Japanese Premiere Minister Noda December 15, 2011 Sefuri the ILC is the project that Japan should promote as a national commitment To build the world science center in Japan Science research is not only about technology and science, but also contributes to the culture and mentality of the citizens
Looking towards the East 37
Japanese plans for a Science City 38
Example Construction Schedule 39
TeV Parameters (2 sets) Beam energy GeV 500 Collision rate Hz Number of bunches Bunch population 10 10 4 2450 1.74 P AC constrained 300 MW Bunch separation Pulse current ns ma 366 7.6 RMS bunch length mm 0.25 0.225 Electron RMS energy spread 0.08 0.09 Positron RMS energy spread 0.04 0.05 Electron polarisation % 80 Positron polarisation % 30 shorter bunch length (within BC range) Horizontal emittance Vertical emittance mm nm 10 30 IP horizontal beta function mm 22.6 11.0 IP vertical beta function mm 0.25 IP RMS horizontal beam size nm 481 335 IP RMS veritcal beam size nm 2.8 horizontal focusing main difference Luminosity 10 34 cm -2 s -1 3.6 4.9 Fraction of luminosity in top 1% 0.6 0.4 Average energy loss 0.06 0.11 Number of pairs per bunch crossing 10 3 200 383 Total pair energy per bunch crossing TeV 1338 3441 low and high beamstrahlung 40
What s next? 20 years from 1 st idea to 1 st prototype SLC 25 more years to a complete ILC design 2013 TDR complete, Technical- and Cost-Reviews done Linear Collider Collaboration is being formed Japan plans to select a site this summer 2013-2016 Prepare a proposal to the funding agencies 2016 The ILC is Good to Go Quote from ILCSC chair Jonathan Bagger at LC2013 DESY 41
ILC accelerator activities at KOREA 42
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Beam test of position resolution of KNU IP-BPM at ATF2 (Feb. 2011) I signal Q signal
Position resolution of KNU IP-BPM at ATF2 ( 70 nm @ Feb. 2011) X X X Residual value = measured position predicted position Beam position prediction Convert to residual X X X Residual Gaussian fitting Beam position measurement Resolution 70.44 nm
New BPMs and Electronics are under fabrications for installation at ATF2 in Nov. 2011. Development of Upgrade version of KNU IP-BPM at ATF2 ( for position resolution of 2 nm)