1. WG5 Cavities Topics as listed by organizers Cavities (Baseline and Hi Gradient R&D) Materials R&D Input coupler Tuners Fabrication Processing (including.EP, HT…) String Assembly Industrialization These noted by “*” in what follows

2. Work plan Before Snowmass –Preliminary Strawman choice for “ baseline recommendation” (BCD) –And alternative(s) for Alternate Configuration Design (ACD) Baseline NEED NOT be present existence proof Enumerate justification of baseline and alternatives –Pros and cons of choices, technical advantages/disadv –Potential Mods or improvements to choices –Technical advantages, Increased technical potential –Potential cost reductions –Risk and reliability impacts –R&D necessary and time scale Of the baseline Of alternatives to supersede baseline status.

3. Proposed methodology We propose to put forward a set of “ preliminary ” reference design parameter choices and prioritized alternatives prior to the meeting. In the discussion/ presentation sessions we will ask for people who do not believe a particular reference selection correct, that they present arguments for alternative to the selected choice. Improvements to and needed design reviews of the choice would follow This discussion would be followed by discussions of alternative options and their priority, and importance. Leading to an R&D plan For instance -

4. Steps for design convergence and R&D plan  ｷ Put out a draft of tentative parameter items choices Prior to Snowmass  ｷ Encourage people to make arguments that other alternatives are better for “ base line ” choice  ｷ Change selection if appears justified-consensus –o make lists of pros & cons  ｷ Discuss work to be done or to be reviewed on the primary choice (its R&D)  ｷ Discuss and prioritize other options  ｷ Outline their needed R&D Identify potential cost reduction, technical risk, technical advantages, increased potential

5. Schedule at Snowmass Agenda WG 5 Week one Aug 15- 19 Tues Day 2 60, 120, 90 (what do the numbers mean?) WG 2- Mod, Kly, llrf, RF dist WG 5-  ｷ Review of strawman for BCD,  ｷ Cavities, geometries?  ｷ Gradient and Q0 R&D goals & LC spec,  ｷ Fab, Processing &  ｷ Industrialization Resources of cavity test

6. Wed Day 3 120, 120, GG90 WG 2&5 – Cryo module, Couplers.., Cryo temp opt WG 2 & 5? with GG3 (availability- Cryo systems, tunnel layout, modulators) WG5 and 2? with GG1? on gradient issues, and packing factor/ slot length? Thurs Day 4 120, 120, GG90 WG 5 Morning- Materials R&D – and basic research towards BCD and ACD tuners (including step motors), and mag shielding Afternoon Draft Conclusions - some with WG2? WG5 with GG availability, tuners, ?? …

7. Criteria Baseline recommendation –Need not be an existing design, but should be either A mature design or procedure A modification easy to extrapolate to without significant R&D program A design or procedure, though not completely certified, likely to be the one of choice One for which costing with contingencies is possible or available One with such significant benefit over existing concept to warrant its choice Should have a clearly defined R&D path to bring to credible stage

8. Criteria cont1 Primary alternative to baseline –Design or concept warranting aggressive R&D effort. –Likely to overtake baseline if pursued –Likely to have significant technical or cost advantages –Define R&D required to bring to credible stage

9. WG5 Cavities Topics General parameters & concepts –Gradient & Q –Goal for cavity R&D –Specification for ILC 500 –Reserve –Reliability & Risk –Cost- benefit –Linac packing factor Cavity types –Needs evaluations of all aspects. –TESLA -Mods to TESLA? Beam pipe length & diameter HOM and pickups Helium vessel & Conical end End group cooling, end group design Flanges and Sealings General design cleanup

10. WG5 topics cont 1 Cavity types continued –Low loss - impact of smaller iris?,cell to cell coupling, beam dynamics, alignment tolerances –Reentrant- or hybrid reentrant - cleaning & structural –Other variants –Superstructure *Hi Gradient R&D –Processing BCP w Ti & 1200C, EP, mechanical grinding, 120 bake BCP w single crystal, or large grain Understand process parameters to reduce spreads Discuss paths toward industrialization –Processing toward industrialization (see industrialization) –Margin & qualification specifications What gradient margin, Q margin What dark current and x-rays –Risks - vacuum accidents

11. WG5 topics cont 2 *Materials R&D –Do we need 1300 C Ti treatment? –Single & large grain Connection w processing –Nb/Cu –Basic reaserch Q improvements *Fabrication –E beam –Hydroform –Spin –Tolerances –End groups - can one improve fab efficiency? *Industrialization –Key issues toward –A plan and schedule –Quality control & reproducibility

12. WG5 topics cont 3 Tuners –Types mechanical End type Saclay Blade type Coaxial Other –Piezo (range for highest gradient?) –Magnetostrictive –Motors- warm vs cold Magnetic shielding

13. WG5 with WG2 topics cont 4 *Input couplers –Varieties –New ideas –Processing –Cost drivers –R&D for cost or processing CryoModule –The string: bellows, GVs, HOM abs, BPM/Quad –The quad/BPM location –Cavity slot length –Cavity & module Interconnect and their real estate –Generic module types With quad/ without q/ separate quad module

14. Cavities WG5 key people DESY –Dieter Proch –Lutz Lilje –W-D Moeller –R Brinkmann –Detlef Reschke –J Sekutowicz KEK-Japan –Kenji Saito –Toshiyasu Higo –Yasuo Higashi –Eiji Kako –Shuichi Noguchi –Hiroshi Matsumoto –Sergey Kazakov –Kenji Ueno JLab –Peter Kneisel –Bob Rimmer –Charles Reece –Jean Delayen –Warren Funk This is just a first attempt at trying to identify people from the overall list. As I don’t know people at some Labs well there may be gross oversites Or errors For instance Cornell???

15. Cavities WG5 key people cont 1 FNAL –Pierre Bauer –Harry Carter –H Edwards –Mike Foley –Don Mitchell –Nikolay Solyak SLAC –Chris Adolphsen –J Cornuelle Saclay/Orsay –Terry Garvey –O Napoly Cornell –Hasan Padamsee (2nd week) –Mathias Liepe –Rongli Geng INFN –Carlo Pagani Industry –Michael Peiniger –Tony Favale –Tony Nelson? Other –John Corlett –Brian Rusnak

16. Couplers (with WG5) Chris Adolphsen transp Progress in processing TTF3 couplers at Orsay Status of new designs Plans for characterizing coupler performance for 35 MV/m operation Modeling of coupler multipacting Proposed tests to understand the coupler processing limits Coupler plans for the XFEL ILC industrialization and cost issues FNAL –Nikolay Solyak –Don Mitchell KEK –Hiroshi Matsumoto –Sergey Kazakov –Shuichi Noguchi –Eiji Kako Cornell –Sergey Belomestnykh LLNL –Brian Rusnak Orsay –Terry Garvey –Alessandro Variola DESY –W-D Moeller

17. Cryomodules (with WG5) Chris Adolphsen transp Status of TTF cryomodules Design changes for XFEL-cryomodules Design changes for the ILC Schedule for TTF/XFEL/SMTF prototypes Industrialization of the XFEL cryomodules Identification of critical requirements Existing and planned cryomodule infrastructures Cryomodule integration issues –Separate Quad / Cavity sections Adoption of international standards FNAL –Harry Carter, Tug Arkan, Cristian Baffo, Don Mitchell, Nikolay Solyak, Andrew Hocker, Helen Edwards –Tom Peterson (or Tom Nicol) ? JLAB –Warren Funk, Peter Kneisel, Jean Delayen, Rimmer, Reece, Preble Cornell –M. Liepe DESY –Lutz Lilje, Carlo Pagani, Dieter Proch, Detlef Reschke, B. Peterson KEK –Shuichi Noguchi, Kenji Saito, Fumio Furuta, Yuichi Morozumi, Toshiyasu Higo, Eiji Kako, Norihito Ohuchi

18. Baseline Configuration Document Chris Adolphsen transp Tunnel Layout –Cut and Cover –TDR like –Deep (> 20m) Tunnels Modulators –Pulse Transformer –Marx Generator –Other Klystron –Power Level –Multibeam tube –Sheet beam tube –Other RF Distribution –TDR like –Other configurations At Snowmass, outline linac choices, giving pro’s and con’s for various items or specifying those to which there is general agreement Quad and BPM package –Integrated at center –Integrated at end –Separate Quad –Cos(2Phi) 80 mm bore –Superferric 40 mm bore BPM –Narrow band cavity –Wide band Cryo Cooling Issues –Segmentation –Shield temperatures –Overhead Other –Modulator/Klystron Cooling –Tunnel Electronics Coupler –TTF3 –Higher power variation –Waveguide like Cavity Design –TDR –Low Loss Cavity Gradient –25, 30, 35 MV/m –Dark current limits Cavity Tuners –End –Blade –Other Cavities per Cryomodule –8 to 12