1. VISIT to DESY and SACLAY Tuners for SRF cavities XFEL cavities testing workflow Yu.Pischalnikov 05/07/2012

2. XFEL Tuner Status (XFEL have ordered 800 tuner mechanisms) (meeting with Lutz Lilje) XFEL Tuner is SACLAY-I design – Successfully used at FLASH CM1 equipped with SACLAY-I tuner Double Lever (1:17); Max forces applied to Motor/actuator /shaft unit less than 200N; Fast/fine tuner C-clamp with 2 piezo;

3. XFEL Tuner Motor/actuator/shaft status XFEL specification: – Push forces (max) 200N; – 30 million steps (anticipate 20 M steps); – min. coarse tuner hysteresis == min. backlash (bandwidth~200Hz);

4. XFEL Tuner Motor/actuator/shaft contenders Two stepper motors:  Phytron motor (Germany)--- special design for cryo-operation ($$)  Sanyo-Denki motor (Japan)--- initial design NOT for cryo-operation ($) Actuator (Gear box):  Harmonic Drive( HD, Germany)  Planetary Gear (Phytron, Germany) Shaft/nut  CuBe&SS( HD, Germany)  SS&SS(Phytron, Germany)

5. Phytron Motor/Actuator for DESY/XFEL  Major market for Phytron product- aerospace/ defense industry;  History of operation, in FLASH and elsewhere ;  More expensive of the two motors  More sophisticated design  Integrated motor/planetary drive units – standard Phytron product  Cold/insulated vacuum tests showed lifetime well beyond XFEL specification (65Mstep…)  Integrated copper ring and tab for thermal sink

6. DESY +Sanyo-Denki motor (Japan)+ Harmonics Drive (HD, Germany) R&D program to modify motor/actuator to reach XFEL requirements http://www.dicronite.com/ More detail info about selection/parameters of different coating/dry lubricant At Tom Peterson presentation “Tuner notes DESY visit, 29Feb 2012” Bearing from GRW- Gebr.Reinfur GmbH&Co

7. XFEL motor/actuator/shaft DESY will buy 820 integrated assemblies of harmonics drive and motor from the harmonics drive company - Harmonics drive company subcontracts motors to Sanyo (Stepper motor from Sanyo (XS-735-010).. I=1.1A V=3.9V) Motors/units will be tested (just several ksteps) at 80K (inside the bag???) Price of 820units ~1.5MEuro== (2.4k$ per unit) CuBe shaft

8. Piezo tuner for XFEL Piezoactuators from PI Ceramics (10*10*36mm 3 ) Company will assemble piezo inside fast tuner fixture and test for 10 6 cycles (WARM) Preload 1-2kN during assembly Order --16000 piezoactuators 430kEuro (270$ per unit….) Question/discussion: shearing forces on the piezo & damage of ceramic endplates? Answer: DESY will relay on expertise of PI Ceramics

9. Question: Why Sanyo but not Phytron? (And how we could use DESY experience to design (or modify existing design) of tuner for FNAL’s projects: CM3,4,5 SSR1, 650MHz tuners design) Cost? – Cost of Phytron option ~20-30% higher… Reliability? – Definitely Phytron has more experience in building electromechanical system for cold/vacuum environment Performances? – Backlash of planetary VS harmonics gears and how it will change of slow/coarse tuner hysteresis curve

10. Tuner Performances One the reason (main?) provided by Lutz for HD vs Planetary gear: – Backlash of Phytron planetary gear box is large than HD gear. From the catalogs backlash of Planetary gear is ~4 times larger than HD – According to Lutz “Carlo Pagani’s team probably have experimental data of tuner parameters with planetary gear and harmonics drive..” Reply from Angelo Bossoti: Unfortunately we haven't experimental comparison between planetary and harmonic drive (HD) gears for what concerns the backlash. “ Unfortunately we haven't experimental comparison between planetary and harmonic drive (HD) gears for what concerns the backlash. We did precise tests at BESSY of small range tuning behavior, but just with Phytron with planetary gear (ZSS2, GPL52). But we never evaluated it (HD) for no tuner model, neither coaxial nor xfel kind, though it was (and in principle it still is) scheduled to do at the BESSY facility, due to lack of time. ”

11. Design of cavity/tuner system rather than backlash of motor/actuator gear box will influence of Frequency VS steps curve A.Bosotti Phytron&Planetary Gear box CM2 Tuner Blade Tuner Phytron&HD

12. On going collaboration with Phytron Objectives: To deliver motor/actuator with Pull/push forces ~1300N 1) FNAL CM3,4,5.. 2) SSR1 Tuner 3) 650MHz Tuner

13. Tuner discussion at SACLAY meeting with Guillaume Devanz Starting from SACLAY II French colleagues designed several version of the Cam&Lever Tuner piezo

14. SACLAY V Tuner for ESS (CAM &LEVER)  SACLAY using “standard from shelf” Phytron product “stepper motor/planetary gear” no forces between body of the actuator and shaft – the same solution E.Borissov used for 3.9GHz tuner  Issues with backlash/hysteresis control by fine tuner/piezo  Piezo tuner for SACLAY II was definitely overdesigned… now they are using much more simple piezo  Discussion of the shearing forces on the piezo & piezo reliabilities -”they are using glue to attach piezo to piezo-holder ?!” SACLAY folks open for collaboration rather just provide drawing for this tuner… First impression: it will be good idea to evaluate this type of design for 650MHz cavity. SACLAY is open to share drawing for SACLAY II version: the same mechanics…

15. XFEL Cavities Testing Workflow (Polish work-package --- team from Poland will contribute to XFEL by testing 800 cavities at 2 VTS (under development at AMTF -DESY )

16. VTS at AMTF (XFEL facilities at DESY) VTS inserts staging area under construction Rad. Shield (concrete) Block moved on rails VTS Dewar

17. TOP PLATE

18. VTS Top Plate/Insert with 4 dressed cavities

19. Summary It is not outlined yet what DESY(XFEL) will select as a cavity testing procedure (???) – go to max. Eacc (still to contribute to ILC R&D… ) – or just reach some fix Eacc and stop.. There are some examples when they test cavities up to 30sMV/m – emitter inside cavity exploded and cavity go down to Eacc=15MV/m Goal of XFEL to have cavity performed inside cryomodule up to 24.3MV/m What will happen if cavity will not pass test at VTS– DESY Vendors will build cavities to “the print” but NOT to the performance (Eacc) DESY will maintain HPR/chemistry facility DESY will do just one shot –… if cavity not recover --- send to storage (???)

20. HTS Facility at SACLAY (example of different approach to rad. shielding)