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 Meeting23/04/2014

2

Outline

• History of the structure: EDMS: 1258457 – traveller of structure EDMS: 1239394 – RF tuning (22-24.08.2012, Vasim+Rolf) EDMS: 1306038 – 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: 1096980, TD18 KEK/SLAC post mortem observations)4. samples (octant/quadrant) for collaborators

• Possible cutting methods• Proposal(s) for TD24

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Cells nomenclature1: input coupler

26: output coupler

5

2: first regular cell 25: last

regular cell

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Cells nb.8h. Records nb.

time3

8

13

18

23

1

5

TD24R05 normalized BD distribution

Hot cells (5 and 6) have appeared from record #50The very high peak values are an artifact of the normalization (if only 2 BDs during a record these cells will result very active)

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5

Comparison of Beadpull measurements

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5 10 15 20 25

-2

-1

0

cell number

Re(

S11

,loca

l) [%

]

Analysis of S11,local

, calculated by Jiaru's tuning program

5 10 15 20 25

-4

-2

0

2

cell number

Im(S

11,lo

cal)

[%]

5 10 15 20 250

2

4

cell number

|S11

,loca

l| [%

]

2012 before HPO

2013 after HPOdifference

Re coupling;little changes

Im detuning;strong 25,26;some 1,2

Preliminary RF measurements analysis of TD24 from CLEX, Rolf Wegner, 14.08.2013

Comparison of detuning of different structures

 T18 SLAC N1 TD18 SLAC T24 SLAC T18 CERN N2 TD24 CLEX TD24 R05 N1

XBox1

Analysed at SLAC SLAC SLAC CERN CERN CERN

by J.W. J.W. J.W. J.S. R.W. R.W.

Output matching    

Standing Wave (VSWR) 1.06 1.22 1.05 1.11 1.05 1.15

R [%] 3.0 10 2.5 5.0 2.6 7.0R [dB] -30 -20 -32 -26 -32 -23

dfend [MHz] +2.0 +7.0 +2.5 +3.0 +0.1 -2.2

dfend-1 [MHz]         +1.0 +1.7

Regular cells    

Total phase shift [°]   -16 6   -9.2 ~ -6

avg(df) [MHz]   +1.0 -0.3   +0.4 +0.2

std(df) [MHz]         +0.2 +0.3

notes Dj19®20 ~ 100° Dj19®20 ~ 100°   Dj19®20 ~ 100° structure retuned

 

Rolf Wegner

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7

Cutting methods

Turning and ripping apartMilling and groovingAbrasive saw cutting

Water-jet cutting

Wire Electrical Discharge Machining (EDM)

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Sawing

8

Cutting methodsCutting method Cutting issues Indicated

for type… Example

1 Saw

High deformationHigh velocity chips and pollution* into the cavity(*The pollution due to cooling liquids could be reduced or even suppressed)

damped TD18KEK/SLAC

22.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 deformationSparks in the cutting plane and possible oxidation;Pollution into the cavity (de-ionized water)

Damped/ undamped T18 CERN

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Cutting methodsCutting method Cutting issues Indicated

for type… Example Metrology check

BD distribution

on iris

SEM chemical analysis

Detailed SEM

exploration

1 Saw

High deformationHigh velocity chips and pollution* into the cavity(*The pollution due to cooling liquids could be reduced or even suppressed)

damped TD18KEK/SLAC no difficult difficult difficult

22.a Milling-2.b Turning (and ripping

apart)

Very clean method (for undamped only)Possible small deformation

undamped T18 KEK/SLAC limited yes yes yes

3

Wire EDM cut

(Electrical Discharge

Machining)

No deformationSparks in the cutting plane and possible oxidation;Pollution into the cavity (de-ionized water)

Damped/ undamped T18 CERN yes yes no

could be affected by pollution

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Cutting methodsCutting method Cutting issues Indicated

for type… Example Metrology check

BD distribution

on iris

SEM chemical analysis

Detailed SEM

exploration

1 Saw

High deformationHigh velocity chips and pollution* into the cavity(*The pollution due to cooling liquids could be reduced or even suppressed)

damped TD18KEK/SLAC no difficult difficult difficult

22.a Milling-2.b Turning (and ripping

apart)

Very clean method (for undamped only)Possible small deformation

undamped T18 KEK/SLAC limited yes yes yes

3

Wire EDM cut

(Electrical Discharge

Machining)

No deformationSparks in the cutting plane and possible oxidation;Pollution into the cavity (de-ionized water)

Damped/ undamped T18 CERN yes yes no

could be affected by pollution

4Abrasive saw slow cutting

Slow rotation speed implies long time (~days)«clean» methodNo deformation

Damped/ undamped

Never done before

Aquistion of suitable

machine...

yes yes maybe maybe

5 Water jet cutting

No deformationPollution into the cavity

Damped/ undamped

Never done before yes yes no

could be affected by pollution

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11

Cutting issues

• copper-air transition due to the damping waveguides• iris thickness + holes for dimple tuners• length of the structure for rotating support• …

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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&21-22-23 for iris inspection • (cut of central cells 12-14 and metrology check for comparison with couplers)

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13

5

Cutting scheme 1 for TD241. Remove the flanges by EDM2. transverse cutting of the two extremities by EDM3. longitudinal cut for metrology of input and output coupler by EDM4. slicing of cells number 4-5-6&21-22-23 for iris inspection by EDM5. (cut of central cells 12-14 as for step 2 and 3)

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5

Cutting scheme 2 for TD241. Remove the flanges by mechanical sawing2. transverse cutting of the two extremities by mechanical sawing3. longitudinal cut for metrology of input and output coupler by EDM4. slicing of cells number 4-5-6&21-22-23 for iris inspection by mechanical sawing5. (cut of central cells 12-14 as for step 2 and 3)

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5

Cutting scheme 3 for TD241. Remove the flanges by mechanical sawing2. transverse cutting of the two extremities by milling/turning and ripping apart3. longitudinal cut for metrology of input and output coupler by EDM4. slicing of cells number 4-5-6&21-22-23 for iris inspection by milling/turning and ripping apart5. (cut of central cells 12-14 as for step 2 and 3)

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5

Cutting scheme 4 for TD241. Remove the flanges by mechanical sawing2. transverse cutting of the two extremities by abrasive low speed sawing3. longitudinal cut for metrology of input and output coupler by EDM4. slicing of cells number 4-5-6&21-22-23 for iris inspection by abrasive low speed sawing5. (cut of central cells 12-14 as for step 2 and 3)

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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?

STEP option 1 option 2 option 3 option 4

1 removing the flanges EDM mech.

sawingmech. sawing

mech. sawing

2 transverse cutting EDM mech.

sawingmilling/turning

abrasive slow sawing

3 longitudinal cutting EDM EDM EDM EDM

4 slicing of cells 4-5-6&21-22-23 EDM mech.

sawingmilling/turning

abrasive slow sawing

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THANK YOU FOR YOUR ATTENTION

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https://edms.cern.ch/file/1093645/2/CLIAAS120079_-_ASSEMBLY.pdf

TD24_vg1.8_R05

input ports

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https://edms.cern.ch/file/1093645/2/CLIAAS120077_-_STANDARD_CELL.pdf

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