1. A Few Pointers from the Linac4 Beam Commissioning of Warm Linac Yngve Levinsen Beam Physics Section www.europeanspallationsource.se 05/02/16

2. Linac4 Overview 2

3. 3 Linac 4 ESS

4. Linac4 Overview 4 Figure borrowed from [4]

5. Linac4 Overview – Front End 5 Courtesy J-B Lallement

6. Linac4 Overview 6 linac4_virtual_tour.wmv

7. MEBT Schematic Overview 7 Courtesy J-B Lallement Buncher cavities Chopper cavities Collimator cone BPM FCT Wirescanner

8. 8 Test Bench Courtesy J-B Lallement

9. 9 Test Bench Taken from [5]

10. 50 MeV Commissioning 10 Courtesy J-B Lallement

11. Summary of week 45 Yngve was present for entire week, 2. Nov – 6. Nov Renato was present for entire week following A peak into an actual week of commissioning Some things will be different for us, some things will be similar 11

12. One Week of Scheduled Beam Commissioning (DTL 2-3) Monday: Delays getting access card (1 st day of month), tank 1 had been commissioned week prior, interlock problems, unfamiliar applications, logic not always understood, 50% beam lost in MEBT, quad polarity -> access Tuesday: vacuum problem during night -> source issues, 5pm first beam commissioning of day (they quit at 6), RFQ sparking, attempt to measure beam energy in MEBT with test stand Wednesday: buncher cavities calibrated, RF expert came in at end of day to warn about potential serious damage to bunchers if left on. Thursday: nothing, major intervention on buncher cavities Friday: still intervention in morning, after lunch buncher cav. Commissioned -> factor 2 improved transmission, finally trying to debug the issues with tank 2&3. 12

13. A Few Thoughts Linac4 commissioning is manpower limited. Only day shift available for beam commissioning. About 2-3 people are actually doing beam commissioning, all with other projects going on. Expert applications are typically written by experts. They will be hard to use by operators unless thorough preparations&training are done. Generic tools such as correlation tools, data collection & parameter scan tools are very useful during commissioning. 13

14. Some More Thoughts Masking interlocks is the name of the game There will be surprises Linac4 team is manpower limited, so ESS could perhaps have benefited from having one person working on the Linac4 commissioning for an extended period and gain experience. 1 week is quite short period for such a visit and most likely a lower limit. With a bit of bad luck nothing will be going on. 14

15. Display Examples – History plot (vacuum) 15 RFQ ramp up

16. Display Examples – Synoptic Viewer 16

17. Displays Examples 17

18. Display Examples 18

19. ESS Control Room Applications 19

20. ESS Control Room Applications 20

21. ESS Control Room Applications 21 Quick prototyping with scripts Many existing applications we can reuse with minimal effort

22. ToF measurements It was already used at 12 MeV commissioning stage. Measure the energy by scanning the phase of a DTL tank for different amplitudes. Compare the result by simulations and deduce the operational amplitude and phase. Repeat the procedure for each DTL tank. 22 Tank-1Tank-2Tank-3 Measurement Bench Tank-1Tank-2Tank-3 Measurement Bench Tank-1Tank-2Tank-3 Measurement Bench Slide courtesy Dimov, Lallement & Lombardi

23. Measurements Tank1: 12 MeV 23 Lines: simulation Dots: Measurement Slide courtesy Dimov, Lallement & Lombardi

24. Measurements Tank2: 31.5 MeV 24 Lines: simulation Dots: Measurement Slide courtesy Dimov, Lallement & Lombardi

25. Thanks A great big thanks to the Linac4 commissioning team, and in particular Alessandra Lombardi, Jean-Baptiste Lallement & Veliko Dimov for this opportunity and being extremely helpful during the visit! 25

26. References 1.Commissioning and Operational Experience Gained with the Linac4 RFQ at CERNCommissioning and Operational Experience Gained with the Linac4 RFQ at CERN 2.Transverse Beam Profile Measurements in the Linac4 MEBTTransverse Beam Profile Measurements in the Linac4 MEBT 3.Status and plans for Linac4 installation and commissioningStatus and plans for Linac4 installation and commissioning 4.Linac4: Progress on Hardware and Beam Commissioning 5.User Specifications for Linac4 Test Bench Diagnostics 6.http://cern.ch/linac4-project/http://cern.ch/linac4-project/ 26