1. Findings in RF Power Couplers after operation on cavities in PXFEL2
TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy
Denis Kostin, MHF-SL, DESY.
Findings in RF Power Couplers after operation on cavities in PXFEL2
How to edit the title slide
Upper area: Title of your talk, max. 2 rows of the defined size (55 pt)
Lower area (subtitle): Conference/meeting/workshop, location, date, your name and affiliation, max. 4 rows of the defined size (32 pt)
Change the partner logos or add others in the last row.

2. RF Power Couplers Investigation Summary
Overview
RF Power Coupler
Module Test
RF Power Couplers Investigation
Summary
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

3. RF Power Coupler cavity warm 300K window cold part warm part
cold 70K window
waveguide part
RF power coupler
cavity
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

4. RF Coupler Sensors / Diagnostics
3 times e- (charged particles)
light in coupler vacuum
light in wave guide (air side)
temperature cold ceramic
temperature warm ceramic
vacuum coupler
vacuum cavity
bias voltage
cryogenic OK
interlock
low level RF gate on klystron
all sensors data is stored for the analysis
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

5. Cryo Module Test Bench
Before you start editing the slides of your talk change to the Master Slide view: Menu button “View”, Master, Slide Master:
Edit the following 2 items in the 1st slide: 1) 1st row in the violet header: Delete the existent text and write the title of your talk into this text field 2) The 2 rows in the footer area: Delete the text and write the information regarding your talk (same as on the Title Slide) into this text field.
If you want to use more partner logos position them left beside the DESY logo in the footer area Close Master View
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

6. RF Couplers Conditioning History/Data (1)
warm coupler conditioning
module PXFEL2: 20 µs pulses
warm part vacuum
at low RF power
coupler 2 e- probe signal
warm part 1,3 activity
Warm RF power coupler conditioning with 20μs pulse up to 800kW was limited by warm parts of couplers 1 and 3.
Coupler 2 electron probe current was increased.
Light.C1 IL events
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

7. RF Couplers Conditioning History/Data (2)
50, 100, 200, 400, 800, 1300 μs pulses
warm coupler conditioning
warm part vacuum
limiting
Warm RF power coupler conditioning was generally limited by warm parts of couplers 1 and 3. Coupler 2 electron probe current was increased as well.
High level of light (PM) signals with warm window temperature increase and relatively low measured electron probe current for couplers 1 and 3 points to the warm window problems.
Warm couplers conditioning was not completed: warm parts 1 and 3 activity persisted.
coupler 2 e- probe signal
warm part 1,3 activity
Light.C1 IL events
T300K1,3 is increased
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

8. RF Couplers Conditioning History/Data (3)
50, 100, 200, 400, 800, 1300 μs pulses
cold coupler conditioning
warm part vacuum
jumps
Cold RF power coupler conditioning on CMTB was also affected by warm parts of couplers 1 and 3.
High level of light (PM) signals with warm window temperature increase for couplers 1 and 3 measured.
Warm parts 1 and 3 activity persisted.
Light 1,3 IL events
T300K3 is increased
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

9. RF Couplers Warm Conditioning Time
coupler warm parts problems
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

10. Module Test Results: PXFEL2 cavities gradients
module performance was limited by the cavities, not couplers
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

11. RF Power Couplers Inner Inspection (1)
Cu-ceramics transition
inner coax – conical part
inner coax
coupler conditioning problems: light signal
warm part 1
CP3H45
outer coax
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

12. RF Power Couplers Inner Inspection (2)
warm part 2
CP3H2
cold 70K window CF100 flange
coupler conditioning problems: e- probe signal
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

13. RF Power Couplers Inner Inspection (3)
Cu-ceramics transition
ceramics
inner coax
coupler conditioning problems: light signal
warm part 3
CP3H52
outer coax
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

14. RF Power Couplers Inner Inspection (4)
Cu-ceramics transition
warm part 7, CP3H46
did not have direct impact on
the coupler conditioning
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

15. RF Power Couplers Inner Inspection Summary
Warm part 1 (CP3H45): boroscope inner inspection revealed many dark points on conical part of inner conductor at top and bottom position of mounted coupler, discoloration near EB-welding, spots near discoloration at outer conductor, on inner conductor near ceramics some black spots, at conical part of inner conductor to ceramics transition a few black lines, and a very rough surface.
Warm part 2 (CP3H2): in cold 70K window CF100 flange vicinity copper coating is deteriorated.
Warm part 3 (CP3H52): boroscope inner inspection revealed some big dark colored spots on the inside surface of ceramics with some thick lines around discolorations on the ceramics, dark colored area at o'clock position of mounted coupler on the conical part of inner conductor to ceramic transition, copper coating damage on the surface of inner conductor at 3 o'clock position, rather rough surface of inner conductor at transition to the conical part, also rough surface of outer conductor near ceramics, some small black points on surfaces of inner and outer conductors.
Warm part 7 (CP3H46): boroscope inner inspection revealed a few black lines and spots on conical part of inner conductor, in this area surface is very rough, in the area between the conical part of the inner conductor and ceramics dark colored area found, few black points on conical part of inner conductor discovered as well.
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy

16. Summary
Warm coupler conditioning was slowed down due to activity (RF discharge) in several warm TTF3 coupler parts and was not completed for PXFEL2. Some other modules (module 8, PXFEL1,3) did have similar problems during the warm coupler conditioning.
For the problem cases RF discharge was mostly concentrated near the warm window: Light (PM) signal was limiting the conditioning, in some cases the spark detector (diode) was following the light signal - detecting the discharge light emission through the ceramic window.
Coupler warm parts boroscope inner inspection revealed several surface defects: scratches on the copper or ceramics surfaces, dark spots, discolorations and copper coating deterioration in warm window vicinity. One warm part did have copper coating deterioration (flaking) near cold window flange (electron probe signal was detected for this part during the conditioning).
Coupler warm parts post-production inspection did show the marks from the circonium ceramics EBW covers on the ceramics for the parts 1,3 in this test, but not the traces on the copper surfaces.
Coupler inner surfaces deteriorations are clearly connected with performance degradation and conditioning slow-down. Post-production inspection is important for the coupler parts.
Copy & paste an element from the Clip Board to the particular slide: 1) Click on a box to mark it. 2) Position the mouse pointer on the box frame: Copy! 3) Click on the particular slide: Paste!
How you intend to use the elements is your choice. You can combine the text block style with the background colour in different manner.
How to change the height or the width (or both) of a box (including its background): Mark the box, and grip and draw the specific edge of the box frame.
You can position a text block inside a frame: 1) Mark the text block. 2) Click on the menu point “Format”: “Text box”, “Text Box”, “Text Anchor Point”.
Insert a new slide: Menu button “New Slide” For more bullet levels (max. 5) use the tab stop button  on your keyboard, back with 
The default colour scheme for font, line and fill is (1st row, from left to right): White  Violet  Grey  Black  Violet  Orange  Violet  Orange
Denis Kostin, MHF-SL, DESY TESLA Technology Collaboration (TTC) Meeting, February 28 - March , Milano, Italy