TD24 R05 N1 after high-power test analysis plans A. Degiovanni, M. Aicheler, N. Mouriz Irazabal, A.T. Perez Fontenla, R. Wegner CLIC RF Structure Development Meeting 23/04/2014

Outline History of the structure:  EDMS: – traveller of structure  EDMS: – RF tuning ( , Vasim+Rolf)  EDMS: – post high power operation analysis Observations:  detuning of coupling cells (last cell frequency decrease, opposite to T(D)18)  hot cell developed during high power operations (  Wilfrid’s analysis) What needs to be done? 1.metrology measurements (for better understanding detuning effect) 2.hot cells analysis (BD distribution) 3.B-arc features (EDMS: , TD18 KEK/SLAC post mortem observations) 4.samples (octant/quadrant) for collaborators Possible cutting methods Proposal(s) for TD24 23/04/20142

Cells nomenclature 1: input coupler 26: output coupler 5 2: first regular cell 25: last regular cell 23/04/20143

Cells nb. 8h. Records nb. time TD24R05 normalized BD distribution Hot cells (5 and 6) have appeared from record #50 The very high peak values are an artifact of the normalization (if only 2 BDs during a record these cells will result very active) 23/04/20144

Comparison of Beadpull measurements 23/04/20145 Re  coupling; little changes Im  detuning; strong 25,26; some 1,2 Preliminary RF measurements analysis of TD24 from CLEX, Rolf Wegner,

Comparison of detuning of different structures T18 SLAC N1TD18 SLACT24 SLACT18 CERN N2TD24 CLEXTD24 R05 N1 XBox1 Analysed atSLAC CERN byJ.W. J.S.R.W. Output matching Standing Wave (VSWR) R [%] R [dB] df end [MHz] df end-1 [MHz] Regular cells Total phase shift [°] ~ -6 avg(df) [MHz] std(df) [MHz] notes  19  20 ~ 100° structure retuned Rolf Wegner 23/04/20146

Cutting methods Turning and ripping apart Milling and grooving Abrasive saw cutting Water-jet cutting Wire Electrical Discharge Machining (EDM) 23/04/20147 Sawing

Cutting methods Cutting method Cutting issues Indicated for type… Example 1Saw High deformation High velocity chips and pollution* into the cavity (*The pollution due to cooling liquids could be reduced or even suppressed) damped TD18 KEK/SLAC 2 2.a Milling- 2.b Turning (and ripping apart) Very clean method (for undamped only) Possible small deformation undamped T18 KEK/SLAC 3 Wire EDM cut (Electrical Discharge Machining) No deformation Sparks in the cutting plane and possible oxidation; Pollution into the cavity (de-ionized water) Damped/ undamped T18 CERN 23/04/20148

Cutting methods Cutting method Cutting issues Indicated for type… Example Metrology check BD distribution on iris SEM chemical analysis Detailed SEM exploration 1Saw High deformation High velocity chips and pollution* into the cavity (*The pollution due to cooling liquids could be reduced or even suppressed) damped TD18 KEK/SLAC nodifficult 2 2.a Milling- 2.b Turning (and ripping apart) Very clean method (for undamped only) Possible small deformation undamped T18 KEK/SLAC limitedyes 3 Wire EDM cut (Electrical Discharge Machining) No deformation Sparks in the cutting plane and possible oxidation; Pollution into the cavity (de-ionized water) Damped/ undamped T18 CERN yes no could be affected by pollution 23/04/20149

Cutting methods Cutting method Cutting issues Indicated for type… Example Metrology check BD distribution on iris SEM chemical analysis Detailed SEM exploration 1Saw High deformation High velocity chips and pollution* into the cavity (*The pollution due to cooling liquids could be reduced or even suppressed) damped TD18 KEK/SLAC nodifficult 2 2.a Milling- 2.b Turning (and ripping apart) Very clean method (for undamped only) Possible small deformation undamped T18 KEK/SLAC limitedyes 3 Wire EDM cut (Electrical Discharge Machining) No deformation Sparks in the cutting plane and possible oxidation; Pollution into the cavity (de-ionized water) Damped/ undamped T18 CERN yes no could be affected by pollution 4 Abrasive saw slow cutting Slow rotation speed implies long time (~days) «clean» method No deformation Damped/ undamped Never done before Aquistion of suitable machine... yes maybe 5 Water jet cutting No deformation Pollution into the cavity Damped/ undamped Never done before yes no could be affected by pollution 23/04/

Cutting issues copper-air transition due to the damping waveguides iris thickness + holes for dimple tuners length of the structure for rotating support … 23/04/201411

5 Overall cutting scheme for TD24 Remove the flanges transverse cutting of the two extremities longitudinal cut for metrology of input and output coupler slicing of cells number 4-5-6& for iris inspection (cut of central cells and metrology check for comparison with couplers) 23/04/201412

5 Cutting scheme 1 for TD24 1.Remove the flanges by EDM 2.transverse cutting of the two extremities by EDM 3.longitudinal cut for metrology of input and output coupler by EDM 4.slicing of cells number 4-5-6& for iris inspection by EDM 5.(cut of central cells as for step 2 and 3) 23/04/201413

5 Cutting scheme 2 for TD24 1.Remove the flanges by mechanical sawing 2.transverse cutting of the two extremities by mechanical sawing 3.longitudinal cut for metrology of input and output coupler by EDM 4.slicing of cells number 4-5-6& for iris inspection by mechanical sawing 5.(cut of central cells as for step 2 and 3) 23/04/201414

5 Cutting scheme 3 for TD24 1.Remove the flanges by mechanical sawing 2.transverse cutting of the two extremities by milling/turning and ripping apart 3.longitudinal cut for metrology of input and output coupler by EDM 4.slicing of cells number 4-5-6& for iris inspection by milling/turning and ripping apart 5.(cut of central cells as for step 2 and 3) 23/04/201415

5 Cutting scheme 4 for TD24 1.Remove the flanges by mechanical sawing 2.transverse cutting of the two extremities by abrasive low speed sawing 3.longitudinal cut for metrology of input and output coupler by EDM 4.slicing of cells number 4-5-6& for iris inspection by abrasive low speed sawing 5.(cut of central cells as for step 2 and 3) 23/04/201416

Conclusion and discussion Desired measurements: – Metrology on input and output coupler to better understand the observed frequency shift – BD distribution on cell 5 and adjacents to find and locate possible hot spot – other possible surface exploration and analyses (also samples to collaborators) Four proposed options to be chosen from Do we want to study the option of a low speed abrasive saw? Do we want to study the option of the water jet cutting? STEPoption 1option 2option 3option 4 1 removing the flanges EDM mech. sawing 2 transverse cutting EDM mech. sawing milling/ turning abrasive slow sawing 3 longitudinal cutting EDM 4 slicing of cells 4-5-6& EDM mech. sawing milling/ turning abrasive slow sawing 23/04/201417

THANK YOU FOR YOUR ATTENTION 23/04/201418

From presentation 14/08/ /04/ re-tuning of last 2 cells (25, 26) ? pro: clearer picture of detuning of regular cells contra: cell 26 detuned in opposite direction than previous structures. Why? Re-tuning could cover tracks. investigations by cutting, metrology, SEM, etc. geometry changes of last cells => why df 26 = +2 MHz and df 25 = -1.7 MHz investigation of cell 24 (higher dS 11local ) investigation of input side – cells 1, 2 – similar effect as on output side? investigation of cells 4, 5, 6 (slightly abnormal dS 11local, hot cell in this region)

TD24_vg1.8_R05 input ports 23/04/201420

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