1. LCLS-II Button-type BPM (Review) Nikolay Solyak Review, FNAL, Dec. 12, 2014

2. Outline Introduction Specifications XFEL BPM design and performance overview LCLS-II button-type BPM design Assembly and heating issues QA/QC Status of procurement Conclusion

3. Introduction For XFEL two types of “cold” BMP are accepted : button type (70%) and reentrant cavity type (30%), total number is 104. DESY start button-type cold BPM development for XFEL in ~2007, -several design iterations (button design, copper plating, thermo-cycling, type of sealing, etc.) and prototypes are built and tested Industrial studies, process of qualifying of companies, cost optimization. Collaboration with Saclay/CEA and PSI (electronics) Developing QA/QC documentation, tooling and process.

5. LCLS-II Physical requirements (cont.)

6. LCLS-II Physical Requirements (cont.) 6.3 Installation Roll Angle All button-type BPMs will be unrolled (as shown at the left) 6 6. Alignment, Drift, and Electrical Offsets 6.1 The linac BPMs are cold button-types L-band cavities with one BPM inside each cryomodule at the downstream end. 6.2 Position and Charge Resolution Requirements (quoted at 10 pC )

7. European XFEL Button BPM specifications Two BPM types are accepted for XFEL; re- entrant cavity BPM developed by CEA in collaboration with DESY, and a button type BPM, length 170mm. Button-type BPMs will be the standard BPMs for all beamlines, cold (cryomodules) and warm. “Cold BMP“ is rigidly connected to the quadrupoles at the end of the accelerator module string. Button BPM for the CMs, assembled to the SC quadrupole package.

8. XFEL BPM requirements

9. Reentrant cavity

10. BPM design details “Cold" button pickups (linac cryo modules): 78 mm aperture, 20 mm buttons, k = 17 mm First order model of beam position from electrode voltage magnitudes (near origin);

11. Design details (2)

12. CoorTek feedthrough, designed by DESY Button (Copper) Flange (Ti)

13. 13 LCLS-II Planning Meeting, Oct 9-11, 2013

14. 14 LCLS-II Planning Meeting, Oct 9-11, 2013

15. Feedthrough testing at DESY 10 thermocycles from 300K to 4.5K (cold 30 min; warm~30min). A continuous leak check during the test cycles show if there is a broken feedthrough or a leak gasket. This procedure is controlled by a PC.

16. D. Lipka et.all, BUTTON BPM DEVELOPMENT FOR THE EUROPEAN XFEL, DIPAC2011 https://accelconf.web.cern.ch/accelconf/DIPAC2011/papers/mopd19.p df Cu was chosen as the surface of the button to minimize losses The wake loss factor of this BPM with 4 buttons results in kloss= 0.8 V/pC for a beam with 25 μm length.  XFEL Loss at the BPM = 78.7mW at 1nC x 3250 bunches x 30 Hz (wake loss).  LCLS-II: 72.3 mW at 300pC x 10 6 /sec = 0.3.mA Thermo-cycles: Button position changes ≤ 50 μm (300K  4K) Dissipated power and Thermal Properties Heating from wakes T max =11.4K Temperature gradient in ceramics 1.9 K

17. 17 Beam Test at FLASH (2) For 0.2-1 nC charge measured resolution < 30 μm. Dynamic range of ±12 mm demonstrated, Charge resolution of 1%. Summary of tests (2007- 2008) Good linearity ± 12 mm @ 1 nC ± 15 mm @ 0.45 nC

18. About the performance of the button BPMs see: http://ibic2013.org/prepress/papers/wepc21.pdf http://ibic2013.org/prepress/papers/wepc21.pdf Beam Tests (2012)

19. CONSIDERING THAT DESY has for several years been researching technologies relevant to design, construction and operation of the European XFEL project, Fermilab is planning to launch a tendering procedure for the manufacturing beam position monitors to be used inside the accelerator modules, which is considered as a contribution to the SLAC National Accelerator Laboratory LCLS-II Project, DESY and Fermilab cooperate in the framework of the LCLS-II Project, DESY is the creator and owner of secret Know-how relevant for the procurement module beam position monitors, and therefore Fermilab wishes to make use of the Know- how to fulfil its obligations within the LCLS-II Project. The Parties have agreed that before such secret Know-how is made available for the use in a procurement procedure, a License Agreement has to be entered into; License Agreement for the use of DESY know-how between DESY and and Fermilab

20. Article 1 Scope of the License Agreement 1.DESY herewith grants to Fermilab a non-exclusive and royalty-free license to use the Know-how on the unmodified production documents for the cold button BPM including Feedthroughs, as it is used in the E-XFEL accelerator modules, as listed below and attached in Appendix 1 to this Agreement subject to the conditions stated in the present Agreement. Production drawings and 3D CAD model respectively of the BPM body. Technical information on the copper plating process for the BPM body, including naming the company that has produced the copper coating for DESY. DESY drawings of the feedthrough of the button, as they were used in the procurement process. Names of vendors involved in the production process of BPM body and feedthroughs. Permission to procure the same custom made feedthrough from the producer of the XFEL cold button BPM feedthroughs. Simulation results about the dissipated power on the cold button BPMs due to HOM fields inside the accelerator module and signal generation due to the simulated beam Cleaning and assembly procedure

21. LCLS-II BPM Housing

22. Copper plating details

23. LCLS-II BPM housing (3D) Teamcenter

24. LCLS-II BPM design (3D model) Alignment pin holes

25. BPM assemble string in cryomodule BPM MagnetCavity Gate Valve

26. Integration to Cryomodule

27. BPM alignment (with Quadrupole)

28. BPM alignment (details)

29. Documentation (Describe Procurement, QA/QC, cleaning, assembly, packaging & shipping: workflow) (8 Pages)

30. Detailed description of the preparation of the BPM feedthroughs from the acceptance tests to the final checks after installation to the BPM body. Work flow diagrams Description of the handling procedures of the body of the cold button BPM from the acceptance test of the body to the installation to the quadrupole and shipment. Reference to the other documents and workage packages LCLS-II BPM ERD/TRD in preparation (based ob XFEL documentation) Documentation (1)

31. Documentation (2)

32. Cable information has been reviewed by cryomodule instrumentation group and Incorporated in CM instrumentation package. Instrumentation are ready for procurement for pre- production CM RF Cables information

33. BPM Procurement Status BPM housing (incl. copper plating) Bidding process is ends on next Dec. 15, 2014 DESY proposed to built 3 prototypes in house with QC, cleaning, assembly and delivery to FNAL for pre-production CM’s. Preparing purchase order. UHV -feedthrough (with button). -Quotation from CoorsTek (US company) for 12 feedthrough (pre-production) and ~150 (series production). -Start procurement for 12 buttons Next step: – Design tooling for BPM QC, handling, cleaning and thermal cycling - Complete ERD/TRD.

34. UVH-”cold” BPM feedthrough (button) Former PMB, reliable, affordable price, good history, in schedule delivery Titanium Copper Laser welded

35. Conclusion LCLS-II “cold” Button type BPMs are based on XFEL design. This design was tested in cold and warm conditions with beam. Test prove that BMP performance will satisfy LCLS-II requirements (100µm @ 10pC for single bunch resolution) Signed License Agreement between DESY and Fermilab provide LCLS-II access to know-how technology: information, drawings, documentation; vendor information and approval to use this drawing for bid with other vendors Design is completed (minor changes in design were made to fit in CM. It will not affect BPM performance) Drawings are released, integration in CM is done All quotations are received for BPM parts (Dec.15 – last one) Procurement of BPM prototypes for preproduction CM’s in progress. BPM design is ready for procurement BPM ERD/TRD are under development. All documentation will be available thru Teamcenter