1. CERN Grooved Chamber Review
SLAC

2. CERN Requirement

3. Extrusion from ALMAG

4. Design Options Extrude (ALMAG) Minimum groove dimensions
2 mm deep, 1.21mm wide,
overall depth 4mm, 22 degree angle
Groove radii, top 0.003in (0.076mm), bottom 0.005in (0.127mm)
Rework bottom radius with saw cutter
Length 1 meter
Saw: (ROBBJACK)
Machine with special profile gang cutter

5. Possible Mfg Options Extruding (Vendor ALMAG)
Slitting saw type cutter with profile to match groove form (Vendor ROBBJACK)
Electro Discharge Machining (EDM)
Casting
Press forming
Laser for reforming bottom groove
Roll forming/metal folding
Textured metal forming

6. CERN Option Use existing PEP II extrusion
Cut out existing grooves in extrusion
(approx 34 mm wide)
Grooves are approx 3.7 mm deep
Overall depth approx. 7mm but can
be reduced
Weld several sections together
Length as required

7. Existing PEPII Extrusion

8. Mfg Comments Options limited due to very precise requirements
Roundness tolerances beyond normal mfg
1 mm type groove depth/radii are very
small

9. Mfg Comments Extruding Almost meets requirements
Can secondary operation reduce bottom groove radius ?

10. Mfg Comments Slitting Saw Type Profile Cutter
Can very thin profile cutter be mfg & survive metal cutting ?
Gang cutter possible for multi-cut mf

11. Mfg Comments EDM Not a continuous mfg process Short length (15 in max)
Sharp top & bottom groove radii yet to be proven
Relatively expensive

12. Mfg Comments Roll Forming/Metal Folding
Similar to auto radiator cooling fin mfg
Very small pitch would be as issue
Very sharp corner radii would be an issue

13. Mfg Comments Casting Minimal radius may be an issue
Not a continuous mfg process
Limited length capability
Casting material may be an issue
Possible Vendor : Precision Cast Parts in Portland, OR

14. Mfg Comments Press Forming Very sharp corners are a problem
Length may be a problem - dependant on
press platen size
Not a continuous mfg process

15. Mfg Comments Textured Metal Forming
Can groove embossing provide adequate e-cloud profile ?
Would be inserted into chamber
Inexpensive

16. Solution Planning
Saw Cutting : Rework extrusion or full machining with saw
Experiment with new saws
For long range approach : Cerro
Will they license or develop their mfg process for larger bore sizes ?
Who designed their extruder ?
Contact them & arrange a visit (St Louis)
Estimate cost

17. Solution Planning Textured Metal Forming
How close can textured metal be formed to form grooves ?
Will a textures pattern perform the electrical requirements ?
Contact & visit a couple of textures metal manufacturers

18. Solution Planning Chamber Coating
Microwave tube industry has experimented with many coatings – are any applicable to the EC Cloud problem ?
Are nanotubes applicable ?