LARP Rotatable Collimators for LHC Phase II Collimation

1
LARP Rotatable Collimators for LHC Phase II
Collimation
US LHC Accelerator Research Program
BNL - FNAL- LBNL - SLAC

• 09 July 2007
• SLAC RD Status Meeting
• Gene Anzalone, Eric Doyle, Lew Keller, Steve
  Lundgren, Tom Markiewicz

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Braze Test2 Delivered 19 Dec 2006
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Vacuum Bake Test Results 4/1/073x over LHC Spec

• 1st Jaw Braze Test Assembly has been vacuum baked
  at 300 degrees C for 32 hours.
• LHC Requirement 1E-7 Pa 7.5E-10 Torr
• Baseline pressure of Vacuum Test Chamber
• 4.3E-7 Pa (3.2E-9 Torr)
• Pressure w/ 200mm Jaw Assy. in Test Chamber
  4.9E-7 Pa (3.7E-9 Torr)
• Presumed pressure of 200mm lg. Jaw Assy.
  6.0E-8 Pa (4.5E-10 Torr)
• Note above readings were from gauges in the
  foreline, closer to the pump than to the Test
  Chamber. Pressures at the part could be higher.
• New
• SLAC vacuum group has suggested longitudinal
  grooves be incorporated into the inner length of
  jaws incorporated into next prototype
• Next steps
• Sectioning examine braze quality

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6/25/07-7/2/07 Slice Dice Braze Test2
Interior slice polished etched
Longitudinal slice
Evidence of fracturing along grain boundaries
presumed due to too-rapid cooldown after braze
- areas near ends and OD look better Braze
of jaws to hub GOOD 3 of 4 jaw-jaw brazes GOOD
Same fracturing patterns as in other slice
Braze of cooling coils to jaw ID good Braze of
cooling coil bottom to mandrel so-so
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Braze Test 3 200mm mandrel with U-Bend
Upstream end of Mandrel
Tubing Wound and Tack Welded to Mandrel at the
U-Bend
6
Braze Test 3 Coil-to-mandrel braze
23 Apr 07 After 2 braze cycles, OD braze wire
grooves machined
13 Apr 07 Prepped for 1st coil-mandrel braze
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Braze Test 3 8 ¼-round jaws to mandrel/coil
19 June 2007 After 1st Jaw BrazePrepped for 2nd
Braze to fillup jaw-jaw joints
Next steps -Vacuum test (July 15) -Section
examine braze quality
14 June 2007 Jaw Fit Up
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Fear of Copper-Moly Braze Joint Leads to Mini
RD Cycle Devoted to Issue

Initial plan to braze one long Mo shaft with
raised hub to inner radius of Cu mandrel deemed
unworkable Brazing HALF-LENGTH shafts to a COPPER
hub piece and THEN brazing the Cu hub to the Cu
mandrel deemed possible First test if Mo backing
ring sufficient to keep Mo and Cu in good enough
contact for a strong braze joint
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Cu-Mo Hub Braze Test parts
28 Feb 2007 Cu-Mo Braze Test Parts

2
3
4
1 - Mandrel Dummy (not shown) 2 - Mo Shaft
Dummy 3 - Mo Backing Ring 4 - Cu Hub with
braze wire grooves
27 Mar 2007 Cu-Mo Braze In Oven
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Apr 6 Cu-Mo Hub Braze Test Assembly after 3
additional heat cycles (to mimic full assembly
procedure) then sectioned. Cu finger fractured

• Grain boundary issues?
• Possible fracturing?

Cu-Mo joints we care about
1mm expansion gap
Samples sliced polished and sent to Physical
Electronics lab for analysis 4/23 Fractures
evident
Small holes held braze wire
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Two Other Cu-Mo Joints Under ConsiderationParts
for both in fabrication now
Interference Fit
Braze Hub improvement includes a flexible
Molybdenum end that prevents the copper Hub stub
from pulling away from the Mo.
Copper Jaw is constrained on the outside diameter
with Carbon and when heated to 900 degrees C is
forced to yield so that upon cooling to 500
degrees C the inner diameter begins to shrink
onto the Mo Shaft resulting a substantial
interference fit.
Improved Joint with Thick Copper and
Thin-Weakened Mo
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21 Mar 2007 Full length Mandrel In-House
Inspected

• Most groove widths meet specification except for
  a few at each end.
• Positioning of distorted areas could indicate
  damage was done by excessive forces imparted by
  hold down fixturing during machining.
• Future Mandrel drawings will include a note
  warning about potential damage caused by
  excessive clamping forces.

Ready to wind as soon as we understand the Mo
shaft joint
out of specification grooves
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Collimator-Jaw Mounting and Rotation
SystemCompleted 27 May 2007

• Universal Joint Drive Axle Assembly
• Thermal expansion
• Gravity sag
• Differential transverse displacement

End support and rotation drive based on Geneva
Mechanism (upbeam side)
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Exploded view of CAD model of Flex Mount

U-Joint Flexes for Shaft sag and Slewing
Triple Cog Geneva Drive Wheel required for 512
clicks per facet
Water Cooling Inlet and outlet
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Up Beam Flex Mount Assembly components

Geneva Wheel Actuator (Ultimately, bearings
will be ceramic these steel)
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Up Beam Flex Mount Assembly showing Ratchet and
Actuator
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Test Lab Preparation Finished
Adjacent 16.5 kW Chiller

• Clean space with gantry access
• Basic equipment Granite table, racks, hand tools
• Power supplies to drive heaters
• Chiller plumbed LCW to cool jaw
• 480V wiring for heater power supplies
• required engineering review, safety review, and
  multiple bids (?!)
• Acquire Heaters
• 5kW resistive heaters from OMEGA
• PC Labview
• Rudimentary software tests only
• National Instruments DAQ with ADCs
• Data Acquisition and Control Module
• 32-Channel Isothermal Terminal Block
• 32-Channel Amplifier
• Thermocouples
• Capacitive Sensors
• Vacuum or Nitrogen (?)
• Safety Authorization (!!!)

Heater Power Supplies staged for installation in
rack
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CONCERN 1 Still have not brazed nor thermally
tested a full length jaw assembly

• Main Steps Still Needed
• After 200mm Jaw tests Completed Satisfactorily
  Freeze brazing protocol
• Jaw 1/4 sections (16 needed of 24 now at SLAC)
  require slight modifications for braze gap
  requirements.
• Moly shaft (at SLAC) will perhaps need to be cut
  in two pieces and brazed to copper hub or
  interference fit made
• Drill Cu mandrel for Moly Shaft
• Wind coil using in-house SLAC Copper,
• Need to order more (Finland 20 week delivery) OFE
  10mm x 10mm or use CERN order of Ni-Cu alloy,
  anneal wind mandrel
• Several braze Cycles
• Drill jaw to accept resistive heater
• Understand (ANSYS) any change to expected
  performance

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Concern2 Still do not have a complete
mechanical (RC1) prototype

• Successful thermal performance of first full
  length jaw
• Complete the design of RC1 RF features
• Fit-up and initial tests of support/rotation
  mechanism on 1st full length jaw
• Complete fabrication of second and third jaws
  (Glidcop?, Moly??) with full support assembly on
  the four corners
• Acquisition of Phase I support mover assemblies
• CERCA/AREVA REFUSES to supply SLAC
• Recent (18 APR 07) proposal to sell SLAC a
  non-functional CERN TCS collimator with damaged
  tank bellows
• Remodeling of CERN parts for interface to US
  parts
• An enlarged vacuum tank has been modeled and some
  CERN support stand modifications have been
  identified
• No fabrication drawings have been done as yet
• Acquire motors, sensors,.. Not part of CERN TCS
  purchase

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Vacuum tank, jaw positioning mechanism and
support base derived from CERN Phase I
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Agreement in Progress to Buy a damaged TCS1
collimator and stand from CERN
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Detail of Damaged Bellows Adjustment Mechanism
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Resource Loaded Schedule Showing June 2008 for
Full RC1
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LARP Collimator Delivery Schedule
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Phase II Task Summary

• There has been continued progress in design and
  excellent but slow progress on the necessary
  small scale projects to finalize procedures.
• Time estimates for thermal test of first jaw and
  construction of first 2 jaw prototype (RC1) are
  expanding. In June 2006 DOE was told
• Expect thermal tests and completely tested RC1
  device by end of FY06 and mid-FY07,
  respectively
• Now need to say
• Expect thermal tests to begin and completely
  tested RC1 device by end of FY07 and end-FY08,
  respectively
• Jeff Smith (Ph.D., Cornell) joins SLAC
  Collimation team July 23, 2007
• 25 ILC, 75 LARP

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CERN Collimation Plan Scheduleas of 22 June
200746 FTE-Years (25-28 FTEs in thru Oct-09)

• 0) Assume SLAC LARP develops Rotatable Collimator
• 1) Develop TWO other complementary designs
• 2) Develop a test stand for the three designs
• 3) Fabricate 30 Phase II collimators of chosen
  design 6 spares
• The target schedule for phase 2 of LHC
  collimation
• 2005 Start of phase 2 collimator RD at SLAC
  (LARP) with CERN support.
• 2008-01 Start of phase 2 collimator RD at CERN.
• -03 Conceptual Design prototyping of Phase II
  Design complete
• 2009-09 Completion of three full phase 2
  collimator prototypes at CERN and SLAC.
• -10 Prototype qualification in a 450 GeV beam
  test stand at CERN.
• 2010-02 Installation of prototypes into the LHC
  and tests with LHC beam at 7 TeV.
• 2010-10 Decision on phase 2 design
• 2011 Production of 36 phase 2 collimators.
• 2012 Installation of 30 phase 2 collimators
  during the 2010/11 shutdown. Commissioning of
  the phase 2 collimation system. LHC ready for
  nominal and higher intensities.