9 cell Vender Qualification test for LCLSII Fulfillment

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9 -cell Vender Qualification test for LCLS-II Fulfillment of contract Phase 1 - RF

9 -cell Vender Qualification test for LCLS-II Fulfillment of contract Phase 1 - RF tests and flux expulsion measurements Ari D. Palczewski, SRF Scientist Jefferson Lab, USA 2/25/2016 - Contract data and slide courtesy of Frank M. High Q 0 working group

Outline • • Venders and Phase 1 contract requirements 9 cell RF results Surface

Outline • • Venders and Phase 1 contract requirements 9 cell RF results Surface resistance fitting to verify doping Flux expulsion measurements – initial results and why this may be a important factor being overlooked in Phase 1

Do. E Subcontract Awardees for Cavity Fabrication (contracts executed 5/29/2015) – Same as X-FEL

Do. E Subcontract Awardees for Cavity Fabrication (contracts executed 5/29/2015) – Same as X-FEL venders • Ettore Zanon, S. p. A. Schio, Italy • RI Research Instruments Gmb. H Bergisch-Gladbach, Germany 3

Phase I – Vendor Qualification (VQ) – N-doping is part of the usual high-temperature

Phase I – Vendor Qualification (VQ) – N-doping is part of the usual high-temperature vacuum furnace degassing of cavities, vendors already own furnaces – What is required by vendors to complete VQ ? • Upgrade of furnace hardware and software controls to perform N-doping in compliance with specifications defined by the project • Vendors need to strictly adhere to N-doping recipe (‘N 2 A 6 EP 5 μm’) – EP final temperature is controlled below 25 C - JLab verifies process parameters after N-doping - Vendors need to demonstrate successful N-doping ( RF results) on 2 cavities in a row Step H degassing N-Doping Soak Period (‘Annealing’) Temperature (°C) 800 ± 10 Duration 180 ± 5 min 2 min ± 6 sec N-Pressure(m. Torr) 0 26 ± 4 800 ± 10 6 min ± 6 sec 0 4

Phase I – Vendor Qualification (VQ) – ‘Dummy’ Cavities for risk mitigation prior N-doping

Phase I – Vendor Qualification (VQ) – ‘Dummy’ Cavities for risk mitigation prior N-doping of VQ cavities • • Dummy cavities are used to demonstrate proper N-injection and automated N pressure control Each vendor will N-dope 1 dummy prior to VQ cavity Dummy cavities will not be RF tested Dummy cavities are 9 -cell TESLA-type cavities with total surface area similar to LCLS-II cavity 5

Qualification • • Cavity sent to JLab under vacuum Cavities are undressed (no HV)

Qualification • • Cavity sent to JLab under vacuum Cavities are undressed (no HV) Cavities do not have HOM couplers JLab will test at 2. 0 k 1. 8 k and 1. 6 K to “extract” doping amount from RF tests Passing unconditionally 3. 0 e 10 @ 18 MV/m no field emission – i. e. goal Passing any other way - contract states Jlab will decide if doping/EP was correct and can pass without meeting goal if other issues arise. 2 cavities must pass in a row to qualify vender

9 cell test results Zanon passes phase 1 Unconditionally RI phase 1 was under

9 cell test results Zanon passes phase 1 Unconditionally RI phase 1 was under discussion, now passed (see fitting next)

Surface resistance fitting example 1. 6 K 1. 8 K 2. 0 K

Surface resistance fitting example 1. 6 K 1. 8 K 2. 0 K

Fitting from Q vs. Eacc – Temperature dependant “A” to qualify doping The extraction

Fitting from Q vs. Eacc – Temperature dependant “A” to qualify doping The extraction of “A: allows verification of doping

Fitting from Q vs. Eacc – “Temperature Independent”

Fitting from Q vs. Eacc – “Temperature Independent”

Cavity history – none standard, RI 023 closest • TB 9 AES 014 ATI

Cavity history – none standard, RI 023 closest • TB 9 AES 014 ATI Wah Chang material Looks like ~12 hours at 800 C Total material removal ~ 250 -300 microns Was doped once before Zanon doped by accident – only 40 microns removed after doping • TB 9 AES 023 ATI Wah Chang material Cavity fully re-crystallized Cavity had bulk EP, CBP and unknown amount of furnace treatments Most likely >400 microns removed Doped @ Cornel 800 c 5 h N 20 A 0 @ 40 torr At least 8 hours in furnace @ 800 C • TB 9 AES 025 ATI Wah Chang material Heat treated at Cornell ~ 3 Days in furnace @ 850 C+3 hr JLab 800 c, ~ 250 microns total removal • TB 9 RI 023 ATI Wah Chang material ~ 250 microns removal time in furnace 7 hours @ 800 c

Measuring Flux Expulsion During Transition Poor expulsion: BSC/BNC ~ 1. 1 Good expulsion: BSC/BNC

Measuring Flux Expulsion During Transition Poor expulsion: BSC/BNC ~ 1. 1 Good expulsion: BSC/BNC ~ 1. 6 Sam Posen | TTC Meeting, SLAC, 2015 – strong material and history dependence on flux expulsion

Flux expulsion ratio – base temperature to 4 k Flux expulsion ratio 1. 8

Flux expulsion ratio – base temperature to 4 k Flux expulsion ratio 1. 8 Flux ration (unit less) 1. 7 1. 6 1. 5 ri 23_cell 2_full RI 23_cell 8_full 1. 4 AES 023_cell 2_full aes 023_cell 8_full 1. 3 aes 014_cell 2 1. 2 aes 014_cell 8 1. 1 1 0 2 4 6 8 10 12 14 Delta Temperature - iris to iris (K) when eq=9. 25 K The data is from averaging the three magnetometers and the iris to iris temperature when the equator was at 9. 25 K.

RF results – TB 9 AES 014

RF results – TB 9 AES 014

RF results – TB 9 AES 023

RF results – TB 9 AES 023

RF results – TB 9 RI 023

RF results – TB 9 RI 023

Final thoughts • • • In my opinion both venders are fully qualified to

Final thoughts • • • In my opinion both venders are fully qualified to move to phase II It is clear to me that both venders will be able to “dope” cavities during production using the standard recipe without issue It is unclear to me how good the vender doped cavities will be because of the material used in production is not like any used during the R&D phase or vender qualification phase.

Backup

Backup

Phase I – Vendor Qualification (VQ) • E. ZANON: – Dummy cavity N-doping completed

Phase I – Vendor Qualification (VQ) • E. ZANON: – Dummy cavity N-doping completed (9 th October) – We expect N-doping of 1 st VQ cavity mid/end October – 2 nd VQ cavity scheduled for end October/early November • RI: – Dummy cavity N-doping scheduled for 14 th October – 1 st VQ cavity scheduled for 26 th October, 2 nd VQ cavity early Results: November • N 2 injection sequence executed correctly • Pressure range inside required N 2 A 6 limits, i. e. 26 m. Torr ± 15% 1 st furnace N-doping with dummy cavity at E. ZANON (October 2015) 1