ILC Main Linac Design Status Lutz Lilje desy de

ILC Main Linac Design Status Lutz. Lilje@desy. de -MPYBangalore 9. 3. 2006 • General layout – Cryogenic layout • Module layout • Segmentation – Tunnel sizes Lutz Lilje DESY -MPY-

ILC Lutz Lilje DESY -MPY-

Main Linac: Towards an Reference Design Report (RDR) • Since Frascati and the appproval of the BCD several things happened in the main linac layout to get the RDR done – Must-link by C. Adolphsen: • Main Linac RDR Wiki: – http: //www. linearcollider. org/wiki/doku. php? id=rdr: rdr_as: main_linac_home – Cryomodule & Cryogenics Groups are defining cryomodule length and cryoplant layout • First pass generated at Jan 16 -17 CERN meeting, has since been updated – RF Group to work with Civil Group to define the size/layout of support tunnel • Some detailed analysis is under way – diameter is going down again… • Alternate cross section? – Magnet group with specifying the linac quad and corrector package • Reviewing issues • Seperated corrector design Lutz Lilje DESY -MPY-

RDR Linac Definition (Cont) • LET Group has been working resolving beam dynamics related issues at Feb 8 -11 CERN meeting • Work with Instrumentation Group to define diagnostics – List of instruments and issues generated at Jan 17 FNAL meeting • Discussing implications of MPS and availability requirements with Himel et al. Lutz Lilje DESY -MPY-

• Must-read by T. Peterson: Cryogenics – http: //tdserver 1. fnal. gov/peterson/tom/SRF/ILC-cryo-8 Feb 06. ppt – Cryogenics is not only the main linac…. • Heat load revisited – More conservative estimates of static heat leak than in TDR • based on TTF measurements (where all module have a warm-cold transition) – Higher dynamic load due to higher gradient – Keeping the plant sizes below 25 k. W total equivalent 4. 5 K capacity leads to maximum plant spacing of ~2. 3 km • Cryo-segmentation every 560 m – warm or cold? – Use segments to isolate insulating vacuum sections • Not necessarily a warm-cold transition – Introduction of a cold-warm transition could be used for shortening regions that are warmed up for repair work • Faster cooldown • Could be used for Instrumentation and MPS – From the beam dynamics standpoint not absolutely needed – Main disadvantages are • cost • contamination issues – e. g. need to add fast valves at very short distance from cavity surface • increased vulnerability to insulating and beam pipe vacuum failures – MPS issue Lutz Lilje DESY -MPY-

BCD Description -500 Ge. V Layout(Slide lifted from “Positron Source Configuration” by KURIKI Masao and John Sheppard, January 2006. Cryogenic device description in red added by Tom Peterson) Primary esource Up to about 500 Me. V via special SRF cavity/magnet modules totaling about 25 m x 20 MV/m Then up to 5 Ge. V with 21 standard SRF modules 650 MHz SRF, about 10 -15 cavities plus 200 m of CESR-c type SC wigglers, all 3 damping rings e. DR Standard modules (starting at 5 Ge. V) 150 Ge. V Beam Delivery SC magnets and crab cavities System (no quatities yet) Positron Linac 100 Ge. V Helical Undulator In By-Pass Line RTML includes SC solenoids plus 61 SRF modules Photon Collimators IP Target e- Dump 250 Ge. V Standard modules Photon Beam Dump 200 m of SC undulators Auxiliary e- Source Photon Target Adiabatic Matching Device RTML includes SC solenoids plus 61 SRF modules e+ pre-accelerator ~5 Ge. V Up to about 500 Me. V via special SRF cavity/magnet modules totaling about 25 m x 20 MV/m Then up to 5 Ge. V with 21 standard SRF modules e+ DR

Lengths and Packing Factor (from spreadsheet originated by Chris Adolphsen and revised by Tom Peterson) Lutz Lilje DESY -MPY-

Cryoplant Layout in e- Linac Tom Peterson For ILC 500, total of ten 25 k. W @ 4 K plants requiring 52 MW of AC power. Lutz Lilje DESY -MPY-

Towards an ILC Cryomodule (4 th generation) • International Effort between the three regions • Design changes are towards nailing down slot length of components – Costing should be straight-forward from TTF (and possibly XFEL) experience Lutz Lilje DESY -MPY- Slides from Talks by Don Mitchell, Tom Peterson and Others at Jan 16 -17 CERN Meeting

ILC Cryomodule Design Considerations • Move quad package to middle of cryomodule to achieve better support and alignment. • Shorten cavity-to-cavity interconnect and simplify for ease of fabrication and cost reduction. • Overall improved packing factor. • Simplify the assembly procedure. • MLI redesign to reduce hands-on labor costs. • More robust design for shipping. • Reliability of tuner motors in cold operation. • Revaluate cryogenic pipe sizes – partially done for the XFEL already Lutz Lilje DESY -MPY-

Increase diameter beyond X-FEL Review 2 -phase pipe Size and effect of slope Lutz Lilje DESY -MPY-

E. g. : Module pipe sizes increase (T. Peterson – CERN Meeting) Lutz Lilje DESY -MPY-

Inside an ILC cryomodule • Cavity package – Cavity – High power RF coupler – Tuner – Magnet package – …(time won‘t permit) Lutz Lilje DESY -MPY-

Cavity with Frequency Tuner • No BCD Tuner, some designs are very close to requirement – Generic issue to all designs: motor and piezo reliability – Deemed to be feasible, but some R&D needed • E. g Bladetuner – Issue with cavity’s magnetic shielding • Could be also another tuner that does not need inter-cavity space – Just watch out for the cryo-lines… Lutz Lilje DESY -MPY-

Existing DESY Interconnect Design Interconnect: Tesla TDR: 283 mm Currently 344 mm 344 Flange/Bellows Design Specs: • Bolted flange (12 bolts/flange) • Convoluted SS Bellows (10 waves, 54 mm free length, ± 25 mm) -Length of bellows dictated by bolt length, old elastic parameters • Bellows elastic requirements: ± 4 mm (~1 mm thermal + ~3 mm tuning) • Aluminum Alloy 5052 -H 32 Diamond Hex Seal • 7 Ton clamping force, 35 N-m torque/bolt • Mechanical analysis done @ Desy, INFN (Cornelius Martens, Roberto Paulon) Lutz Lilje DESY -MPY-

Proposed Cavity Layout Flange-to-Flange Cavity Spacing = 1319 mm Lutz Lilje DESY -MPY-

BCD assumes use of XFEL Main Coupler Graphics from Terry Garvey Lutz Lilje DESY -MPY-

BPM / Quad / Corrector Package 887 66 BPM 77 666 QUAD and Correctors ILC Preliminary Lutz Lilje DESY -MPY- 78 TDR

Shell Type ILC Dipole Corrector Vladimir Kashikhin, Fermilab Magnet Parameters Integrated field 0. 02 T-m Center field 0. 2 T Winding ampere-turns 18 k. A Current 90 A Superconductor Nb. Ti SC diameter 0. 5 mm Outer diameter 140 mm Magnet length ~ 200 mm Flux density and flux lines at max current in both dipole coils Lutz Lilje DESY -MPY-

ACD: Seperate Quad Cryo-section 1530 mm Lutz Lilje DESY -MPY-

ACD: Pros / Cons for a Separate Quad/BPM Cryostat • Pros – Allows for a common cryomodule design – Flexibility • Accommodation of different magnet packages, upgrades, etc. • Independent adjustments to the quad/BPM position – Handling • Allows independent cold testing and measurement of the magnet package • Schedule, resources, and fabrication facilities not tied to mainstream cryomodule production – Precludes the need for independent quad movers inside the cryomodule (ACD) • Cons – Design issues • Interconnect forces due to bellows could affect quad alignment • Vibrations due to interconnect might need crosscheck – Cost • One extra interconnect required at each quad location – Potentially requires more longitudinal space required in the lattice Lutz Lilje DESY -MPY-

Region between Cryomodules • Assume 850 mm Flange-to-Flange length (TTF) – 850 mm between flanges, 815 mm ‘free’ space – Length partially defined by requirements of cryo tube welding and beam tube assembly (local cleanroom) • Includes – 270 mm Broadband HOM absorber • XFEL design could be used (but likely over-designed) – Manual Gate Valves – Pump-out Ports (integrated in absorber) • Needs to be better defined Lutz Lilje DESY -MPY-

Some critical design issues • ILC specific issues – Quad/corrector/BPM package needs more work • Implication for the next generation cryomodule (type 4) that is being developed by FNAL/INFN – Cavity-to-cavity interconnect design. – Magnetic shield re-design. • Issues for both ILC and XFEL – Tuner reliability, slow and fast. – Vibrational analysis, which will be compared to measurements for verification of the model for future design work. – Development of module and module component tests. – Design of test instrumentation for the module. – Verification of cavity positional stability with thermal cycles. – Robustness for shipping, analysis of shipping restraints and loads, shipping specifications. Lutz Lilje DESY -MPY-

RF System: RF Unit – Solid-state switched modulator with 1: 12 step-up transformer and bouncer droop compensator – 10 MW 1. 3 GHz multi-beam klystron • Currently do not have a robust tube design • Assume horizontal mounting (could be vertical depending on tunnel height) – no such tube built yet. – Waveguide distribution system with three way split to feed 24 cavities – each feed includes isolator and phase shifter / Qext controller. – 680 RF units for cold cavities in ILC 500 – Modulator, Klystron and three-way splitter in support tunnel, rest in accelerator tunnel. Lutz Lilje DESY -MPY-

Examples of RF three-way split Leibfritz, FNAL Fukuda, KEK Lutz Lilje DESY -MPY-

TTF Waveguide Distribution Lutz Lilje DESY -MPY-

Need more compact design (Each Cavity Fed 350 k. W, 1. 5 msec Pulses at 5 Hz) Two of ~ 16, 000 Feeds Lutz Lilje DESY -MPY-

RF System Design – Work so far on • Understanding interface to LLRF system, which is in the Control’s group domain • Compiling list of actuators and signals to be monitored in the linac • Working with civil group on rf system layout in the support tunnel – Distribution system needs more design work to lower cost Lutz Lilje DESY -MPY-

Example: RF System layout Lutz Lilje DESY -MPY-

Example: Implementation using ATCA standard Lutz Lilje DESY -MPY-

Lutz Lilje DESY -MPY-

Civil Facilities: Tunnel Layout • Distance between tunnels based on construction needs, radiation protection is under investigation • Water influx • Tunnel Sizes – Component lists with sizes generated – The 4 m diameter support tunnel and 3. 2 m diameter beam tunnel in BCD are likely too small – Would help to make components narrower – work in progress • A lot of work underway on other details – – – Water and power distribution Air supply and temperature regulation Penetration size and access (e. g. crossover) Transportation and stay clear Personnel access and egress Fire Safety Lutz Lilje DESY -MPY-

Tunnel layout: Component Lists Lutz Lilje DESY -MPY-

Example: 4. 5 m Linac and 5 m Service tunnel Lutz Lilje DESY -MPY-

Service tunnel sizes under discussion: 4. 5 m, 5 m and 5. 5 m Lutz Lilje DESY -MPY-

Installation Systems Concept Development Step Installation Phases & Sequencing

Installation Systems Concept Development Step Installation Phases & Sequencing

Installation Systems Concept Development Step Installation Phases & Sequencing

Installation Systems Concept Development Step Installation Phases & Sequencing

Crossovers between the tunnels Lutz Lilje DESY -MPY-

Diagnostics: Under discussion • Aim for BPM resolution of 0. 3 micron at full charge and 3 micron at reduced charge (10%) when running with keep-alive source. Want to achieve this bunch-by-bunch with bunch spacing down to 185 ns. – Accelerator Physics might be satisfied with less ambitious goals for full charge (~1 um) • Do not implement HOM readout initially, but to bring signals just outside of the cryomodules where they would be terminated. • Use beam coupling to HOM ports to monitor relative bunch intensity and bunch phase relative to rf (use for rf phase control) • Optional: Include 6 -12 m long warm sections after every 48 cryomodules (560 m) • Use for beam line and insulating vacuum isolation. • Each would contain a laser wire: with 21 wires, have 7 independent measurements of emittance along each linac. • Could contain other instrumentation such as beam halo and dark current monitors. • Could contain spoilers for short-train beam abort. • Could be used for cryo-segmentation as discussed earlier • Penalties (as mentioned before): Cost; MPS issues, contamination • Within linacs, measure beam energy and energy spread only for the electron beam in the undulator line. Lutz Lilje DESY -MPY-

Summary • Many discussions on-going – Interplay between Area systems and Technical systems is being defined and starts to work • Very detailed information becoming available – Cryogenics – Module layout • More work needed – Tunnel layout has changed and experts are working e. g. on the component level to further reduce the tunnel size – Costing details need more work: • E. g. How to handle TESLA TDR or XFEL cost estimates? • Is there a ‘common sense‘ to do the costing? • Baseline design exists – Some of the options need more thorough discussion e. g. cryo segmentation Lutz Lilje DESY -MPY-

Thank you… • … to the many colleagues who provided me with transperencies! Lutz Lilje DESY -MPY-