1. LARP Phase II Secondary Collimator RC-1
LARP CM12 Napa, CA
April 9, 2009

2. Introductory Statements
Your comments and/or questions are welcome at any time . There will also be time at the end for an in-depth discussion of any and all aspects of our design.
Sub-title of this talk:
“The Rotatable Collimator from the inside out”
Basic format I hope to follow:
Internal component detail (CAD models and photos of real pieces (RC-0 / RC-1)
Fabrication photos of components of the RC-0 Jaw aka Heater Test Jaw.
Fabrication photos of some of the RC-1 components that are currently in work.
Specifications and physics requirements and how we meet them.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 2 /64

3. Collimator Jaw-Hub-Shaft Concept
Jaw heats up along the side facing the beam and lengthens causing
each end to deflect away from the beam and into the 2mm annular gap
between the Shaft and the Jaw.
The Jaw also swells a bit causing the Jaw face move towards the beam.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 3 /64

4. Jaw heating and deflection characteristics for
Some Calculations
Jaw heating and deflection characteristics for
Steady State (SS) and Transient (TR) conditions
Component SS TR units
Max jaw temp C
Max deflection toward beam μ m
Surface Sagitta μ m
Effective length m
Water temp rise C
Water pressure drop bar
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 4 /64

5. Cutaway of Jaw Assembly
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 5 /64

6. RC-1 Half Shaft and Hub Assembly
This Outer Keeper Ring
is machined off after brazing
in order for Shaft
to pass through Mandrel ID
Cu-Au alloy
braze wire
This Outer Keeper
Ring acts as a stop to
position the Shaft
longitudinally
Outer Keeper Ring
Keeps moly outer finger tips
from splaying out and away from Glidcop during brazing
Inner Keeper Ring
Forces moly inner fingers
to keep up with Glidcop
expansion during brazing
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 6 /64

7. RC-1 Molybdenum Shafts
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 7 /64

8. Details of Ends of Molybdenum Half Shaft
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 8 /64

9. RC-1 Hollow Glidcop Hub (prior to Cu plating & grooving)
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 9 /64

10. Grooving details of Glidcop Hub
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 10 /64

11. RC-0 Half Shaft and Half Hub Brazing
The two Half Hubs
are now one. We
originally
needed to machine out
a copper inner keeper plug
that forced the moly
fingers out with the
Glidcop during brazing
to provide an opening for the tubing.
RC-1 uses a thinner SST
ring that can remain
inside the Shaft with
room for the tubes to pass
through.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 11 /64

12. Mandrel with Cooling Tube
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 12 /64

13. RC-0 Mandrel at QC
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 13 /64

14. RC-1 Mandrel in work
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 14 /64

15. RC-1 Mandrel almost finished (March 15th)
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 15 /64

16. Completed RC-1 Mandrel March 25th
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 16 /64

17. No Vacuum to Water Joints
Tubing is wound into Mandrel groove while free ends pass through the hollow center parallel to each other yet exiting on Shaft centerline. When Collimator rotates the tubes twist on their own axis but not around each other.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 17 /64

18. Tubing coil on turntable for winding
16m of tubing are removed from “loose coils”
UHV cleaned and placed on a turntable for payout.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 18 /64

19. Winding tubing on the RC-0 Mandrel
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 19 /64

20. Nearing the end or… forming the bend
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 20 /64

21. RC-0 Mandrel Brazing Setup
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 21 /64

22. Machining the RC-0 Mandrel to size
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 22 /64

23. Collimator Jaw Brazed to Mandrel
RC-1 Jaw has 5 cylindrical sections.
End sections are tapered.
RC-0 has 16 quarter sections, none are tapered.
The RC-0 Jaw to Mandrel fit up for brazing was quite time consuming & expensive.
Each quarter section had to be reworked to fit Mandrel final diameter!
Changing to full cylinders, to save time & cost, meant they should be a somewhat shorter to be easier to slide over the Mandrel with the tight brazing tolerances.
Robustness test will use 1 RC-0 and 1 RC-1 style Jaw
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 23 /64

24. 16 Jaw Quarters with Cu/Au alloy foils
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 24 /64

25. Jaw Braze preps continue
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 25 /64

26. RC-0 Jaw Brazing Success
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 26 /64

27. RC-1 Jaw braze Assembly
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 27 /64

28. Section of Revised Jaw Cu-Au braze wire go here ~ 40 snap
rings
Braze wires replace foils simplifying
braze preps
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 28 /64

29. RC-1 Final Machining
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 29 /64

30. 20 Facets 20 years? 20.25mm ~15 degree taper at each end
places RF contact bearings
~10mm away from facet.
Facet length = 930mm (oal) – 2x38mm (taper) = 854mm
Taper may be too generous and could be shortened for a longer facet.
Thickness of Glidcop Jaw
(facet to water) is 24.5mm.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 30 /64

31. Flatness Specification is 25 microns over full length of Jaw.
Facet Flatness
Flatness Specification is 25 microns over full length of Jaw.
How did we do?
Generally very good (4 of 5 facets checked met spec).
Worst facet has a sagitta of 43 microns.
How we will do even better!
Newer milling machine.
Competitive bid with specification of 25 micron rather than “best effort”
May suggest vendor perform test mill of dummy piece to qualify process prior to fab.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 31 /64

32. Jaw Facet Preliminary measurement for end-to- end flatness
LARP LHC PHASE II COLL RC1 - S. Lundgren 1 April No 32 /6n
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 32 /64

33. Measuring RC-0 Jaw facet flatness
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 33 /64

34. Link to RC-0 Facet Flatness data
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 34 /64

35. Up Beam end Jaw Support Version 1
Diaphragm allows Jaw end-to-end offset and Shaft sag.
Flex vanes compensate (along with the diaphragm) for Shaft expansion
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 35 /64

36. Jaw Support Development
A few thoughts:
Rigid mount would hold drive gearing in alignment with Shaft.
This would require a flexible connection to the shaft to allow for deflection (sag) due to gravity and Jaw end-to-end offset.
Or a spherical bearing. At the time we were unable to locate a full complement ceramic spherical bearing set.
So… A diaphragm was introduced to attach the gear to the Shaft.
This diaphragm, if designed correctly, should be able to distort not only for the angles but also for the change in length of the Shaft due to thermal effects.
Eventually it was determined that the End Support would need to flex to help the diaphragm absorb the longitudinal expansion. Version 1 was designed.
Finally the current version combines the diaphragm angular distortions with the flexibility of the original End Support.
The final hurdle is to find an acceptable high strength stainless steel to fabricate it from. (Restrictions may eliminate some H.S. stainless steels which contain Co as an alloying element).
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 36 /64

37. Up Beam Jaw Support Current Version
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 37 /64

38. Down Beam Jaw Support Current Version
100 1 mm dia. ceramic
ball bearings roll between
these two races
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 38 /64

39. Cutaway of Jam Nut and Support
100 1mm dia. Ball bearings roll
in “V” groove
Rotation Mechanism mounts
to tab on bearing race
Jam Nuts mate at beveled surfaces to strengthen tip of Support
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 39 /64

40. Outboard Bearing Race/Axle
Buttress Threads
100 1mm ceramic
ball bearings roll
here
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 40 /64

41. Inboard Bearing Race w/gear Drive mounting tab
Bearings roll here
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 41 /64

42. Jam Nut Two of these lock Collimator Jaw to the End Support
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 42 /64

43. Shaft Ends are grooved for ceramic ball bearings
Ceramic bearings roll here and at far end
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 43 /64

44. Shaft End bearing groove details
Bearings roll here
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 44 /64

45. Jaw End Support System w/cooling tube
~100 1mm dia. ball bearings
in End adapter for rotation
(Bellows removed to show
support detail)
Jaw Shaft End rests in slot of Support and is held by jam nuts on either side
Flexible support is high
strength stainless steel
welded to bottom of
bellows cuff at assembly
to Tank Base Plate
Bellows mounting to Drive is unchanged from CERN design
Cooling tube adapter
is tig welded after Jaw
is installed in Tank
“Beefed-up” design still permits Jaw end-to-end offsets (3mm), Shaft thermal expansion and static sag. Deflection is improved for non-horizontal collimator positions.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 45 /64

46. Jaw Rotator/Gear Drive Accuracy
Jaw face alignment specification dictates an indexing type of mechanism. This drive allows up to 8 mis-counts of drive motor steps before Jaw moves off position.
2x1 bevel reduction in combination with 80 x1 worm reduces side load on drive and support to a minimum level.
Worm also provides locking of Jaw.
Backlash is a minimized due to tubing torque load
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 46 /64

47. Indexing the Collimator Jaw
Indexing can be 1 facet, 5 facets for 90 degrees, 10 facets for 180 degrees.
For a distortion of Jaw in the plane of the beam a 90 degree advance would render the distortion a non-problem.
After a 180 degree advance a subsequent hit might correct the distortion, if a were of the same magnitude.
Following a sequence of 10 facets (180 degrees), 1 facet then 10 facets, a total of 5.25 twists of the tubing would be needed to “use up” all 20 facets.
Tubing was twisted an equivalent of 8 times.
No visible defects observed.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 47 /64

48. Twisted Hollow Copper 10mm x 7mm
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 48 /64

49. Ratchet actuation conceptual arrangement
Wire Springs restore
Hammer after ratchet
movement
Hammer contacts
here during
over-travel of Jaw
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 49 /64

50. Jaw End Details for Image Current connection
Bearing races
fit in recess
here
300 Rhodium Plated stainless steel
ball bearings roll here
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 50 /64

51. Image Current Bearing Race (example)
Glidcop
Ring details are similar for both races
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 51 /64

52. Image Current Foil Assembly Version 1
This surface mounts to
bearing race
Height of parts was necessary to shadow the Gear Drive on top of Jaw End Support
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 52 /64

53. Current Version of Foil Assembly
Temp sensor mounts here
Reduced
height
of foil is
minimum
to shadow
“Geneva”
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 53 /64

54. Temperature Sensor/ Image Current Foil mount
Foil Brazes Here
Mounts to
Bearing Race
here
Temp Sensor
mounts here
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 54 /64

55. Current Version of Image Current Foil
1mm x 40mm Glidcop foil will be life cycle deflection tested
This end curves to
conforms to Mount
for brazing
This end curves to
conform and attaches
to Beam pipe Flange ID
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 55 /64

56. Preliminary Tank concept
Tank has tapered features
to prevent upsetting the image current
First transition from round
pipe to square geometry is machined
into the flange end of tank. Flexible Glidcop
foils (not shown) carry image current to second
transition which tapers meet Jaw end.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 56 /64

57. Why the change?
We were interested in the ability to work on the image current components after things were welded up because we may not get it right the first time.
Results from preliminary laboratory RF tests showed that geometry to be less an issue than previously anticipated so the more complicated transitions may not be needed.
We will be hand tig welding the tank together rather than e-beam welding so distortion could be less of an issue.
Pluses:
Uses standard pipe.
Thinner wall results in less radiation effects.
Camera ports for viewing the Jaw face remotely seem a bit simpler to implement.
Minuses:
However, HOM modeling has recently shown high heating loads (larger volume).
Until those issues are resolved this configuration might only be useful for the TT60 tests.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 57 /64

58. New Cylindrical Tank Concept
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 58 /64

59. Cylindrical Tank body
Tank is 355.6mm diameter x 6.35mm wall welded pipe
Material is 304 SST.
Note: Weld seam will be eliminated by cutout at bottom.
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 59 /64

60. Base Plate Base Plate is only slightly larger than CERN design
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 60 /64

61. End Flange Tank End Adapter reduces the Tank dia to a DN250 CF Flange
Material is 304LN, if required, otherwise 304L
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 61 /64

62. Beam Pipe Adapter
End Flange reduces the DN250 CF Flange to DN100 Beam pipe Flange
Material is 304LN, if required, otherwise 304L.
Note: Small hole is for the Camera Viewport Nipple
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 62 /64

63. Assembling the Tank for welding
Collimators were previously assembled to Base Plate and welded into bellows end cuff
All viewports are previously
welded in
End Flanges could be tack
welded to cylinder first
Fixturing holds Cylinder rigid
To retain shape during welding
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 63 /64

64. Proposed TT60 Robustness Test Configuration
Preferred orientation is 0 degrees.
RC-0 & RC-1 Jaws are used.
Collimator mounts on CERN stand.
Cooling water quick connect?
Cables do not?
Laser micrometers mount here
for measuring possible permanent
distortion after beam strike
End ports are 1mm thick titanium.
Vacuum pump (if needed) mounts
to tee at down beam end.
Chain tensioners used on all flanges.
Cameras mount here (both ends)
for remote viewing surface damage
to RC-1 Jaw after beam strike
Beam
DN250 flanges at ends permit access prior
to test and after “cool-down period”
LARP LHC PHASE II COLL RC1 - S. Lundgren 9 April No 64 /64