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LARP Rotatable Collimators for LHC Phase II Collimation
18 April 2007LARP Collaboration Meeting – Fermilab
Tom Markiewicz/SLACRepresenting Gene Anzalone, Eric Doyle, Lew Keller & Steve Lundgren
BNL - FNAL- LBNL - SLAC
US LHC Accelerator Research Program
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 2 / 59
Collimator Design as of April 2006
beam
beam
•136mm diameter x 950 mm long copper jaws (750 mm effective length + 2 x 100mm tapers)
•Vacuum tank, jaw support mechanism and support base derived from CERN Phase I
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 3 / 59
EXTERNAL COIL PERMITS 1 REV OF JAW
CERN PHASE I JAW POSITIONING MECHANISM – USE IF POSSIBLE
25mm thick annular (hollow core) copper jaw backed by continuous helical cooling tube
Collimator Design as of April 2006
NLC Jaw Ratchet Mechanism assumed
Sheet Metal formed RF transition
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 4 / 59
Stop prevents thermal bowing of jaws from intruding on minimum gap. Deal with:
•Residual swelling into beam•External vertical actuator and bellows that also has +/- 5mm transverse float•Mid-jaw recess•Forces possibly unbalanced front vs. back
Leaf springs allow jaw end motion up to 1mm away from beam. Must allow:
•Thermal motion while minimizing gravity-deflection
•Axial expansion
Adjustable central aperture-defining stop and leaf spring support required to prevent jaws
from deforming 1200um into beam
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 5 / 59
One Year Later…
• New jaw-hub-shaft design which eliminates central stop & flexible springs• New reverse-bend winding concept for the cooling coil which eliminates
the 3 end loops, permitting longer jaws and freeing up valuable space for jaw supports, rotation mechanism and RF-features
• Internally actuated drive for rotating after beam abort damages surface
These concepts discussed at October 2006 collaboration meeting
Main accomplishments in the last 6 months• Several test pieces manufactured and examined• Rotation & support mechanism fully designed• All parts for first full length jaw assembly manufactured & in-house• Test lab fully wired, plumbed and equipped
BUT…– Still have not brazed nor thermally tested a full length jaw assembly– Still do not have a complete mechanical (=“RC1”) prototype
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 6 / 59
http://www-project.slac.stanford.edu/ilc/larp/
Monthly meetings with CERN
Up-to-date in labeled folders
Written version of this talk
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 7 / 59
Advances since RC1 Baseline
solid core more cooling
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 8 / 59
New Idea to Eliminate Central Stop Jaw-Hub-Shaft
1. Hub located, in Z, near peak temperature location, which lowers peak temperature, reducing gradient and bending.
2. Max deflection toward beam reduced if the shaft deflection can be minimized
3. Both ends of jaw deflect away from beam. (Note: swelling component of deflection is not corrected.)
4. Cooling coils embedded in I.D. of outer cylinder.
shaft jawhub
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 9 / 59
Max Jaw Temp
Jaw max toward beam
Coll surface sagitta
Eff length
Operating Condition
Jaw Design Deflection Reference
oC m m m Steady State Baseline stop 86.5 36 394 0.43 Baseline shaft 86.5 426 394 0.43 Refined baseline shaft 66.3 238 202 0.63 Jaw-hub-shaft shaft 70.6 84 197 0.74 Transient Baseline stop 231 97 1216 0.24 Baseline shaft 231 1260 1216 0.24 Refined baseline shaft 197 853 913 0.31 Jaw-hub-shaft shaft 224 236 781 0.39
Evaluate jaw-hub-shaft for 950mm jawsw/ 22.5mm deep cooling tubes with hollow Moly shaft
versus 750mm jaw baseline & 750mm jaw solid copper shaft refined baseline
Notes:1. Deflection means deviation from straight (um).2. Eff length is length of jaw (m) deflected <100 um compared to maximum deflection point.3. Deflection is combination of swelling and shaft bending4. Molybdenum shaft static deflection due to gravity = 68um5. 7 min allowable aperture achieved by setting jaws of first collimator at 8.5 .
New Baseline
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 10 / 59
Model showing 42.5 winds of coil on Mandrel with 80mm wide space for U-Bend at downstream end
Restrain each tube on centerline of bearing
200mm
136mm dia
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 11 / 59
Comparison of Hollow Mo shaft and Solid Copper Shaft to same FLUKA secondaries: Improved deflections
Solid Cu, 75cm tapered jaw, asymmetric hub
Tubular Moly, 95 cm straight jaw, symmetric hub
Steady State=1 hour
= 12 min for 10 sec
Steady State=1 hour
= 12 min for 10 sec
Gravity sag 200 um 67.5 um
Power absorbed 11.7 kW 58.5 kW 12.9 kW 64.5 kW
Peak Temp. 66.3 °C 197 °C 66 °C 198 °C
Midjaw x 100 um 339 um 83.6 um 236 um
Effective Length 51 cm 25 cm 74 cm 39 cm
Sagitta 221 um 881 um 197 um 781 um
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 12 / 59
October 2006 Version of Jaw Upstream end with actuator and cooling lines
Lundgren
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 13 / 59
Current Upstream end with actuator and cooling lines
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 14 / 59
Universal Joint Drive Axle Assembly
• Thermal Expansion of molybdenum Shaft of 0.290mm (transient) causes each diaphragm to distort by 0.145mm.
• Shaft sag causes an in plane rotation of the Shaft ends of 0.00025 radians causing an equal distortion of the diaphragm.
• Transverse displacement one of the ends of the Shaft relative to the other by +/- 1.5mm causes an angular distortion of 0.0015 radians in the diaphragm.
• Worst case is for a Vertical Collimator with maximum “slew” of 0.0015 radians added to the sag component of 0.00025 radiansfor a total of 0.00175 radians of bending of the diaphragm.
Lundgren
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 15 / 59
Jaw Mount with Geneva Mechanism
0.5mm thick diaphragm
100 Tooth Worm Gear
Geneva Driver Wheel (on ratchet shaft)
Geneva Driven Wheel(on Worm shaft)
Lundgren
Linear actuator
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 16 / 59
Upstream end vertical section
Jaw
Geneva Mechanism
Support Bearings
Worm GearShaft
Water CoolingChannel
U-Joint Axle
Lundgren
1-2mm Gap
Diaphragm
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 17 / 59
Upstream end horizontal section
Support to Support 1000mm
Overall length 930mm
Facet length ~905mm
LundgrenCollimating Surface RF Transitions
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 18 / 59
Summary of New Baseline Configuration
Jaw consists of a tubular jaw with embedded cooling tubes, a concentric inner shaft joined by a hub located at mid-jaw
– Major thermal jaw deformation away from beam– No centrally located aperture-defining stop– No spring-mounted jaw end supports
Jaw is a 930mm long faceted, 20 sided polygon of GlidcopShorter end taper: 10mm L at 15o (effective length 910mm)Cooling tube is square 10mm Cu w/ 7mm square aperture at depth = 24.5 mmJaw is supported in holder
– jaw rotate-able within holder– jaw/holder is plug-in replacement for Phase I jaw
Nominal aperture setting of FIRST COLLIMATOR as low as 8.5 – Results in minimum aperture > 7 in transient 12 min beam lifetime event
(interactions with first carbon primary TCPV)– Absorbed power relatively insensitive to aperture: for 950mm long jaw
p=12.7kW (7), p=12.4kW (8.23)Auto-retraction not available for some jaw orientationsJaw rotation by means of worm gear/ratchet mechanism “Geneva Mechanism”
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 19 / 59
RF Shielding: Baseline DesignTie-Rods with Fingers Connect Jaws & Tank
Issues:– At a few 10s of grams per finger (.1 mΩ/contact) force causes
excessive deflection of the tie-rod holding fingers– Cooling required
Discussions with CERN and PeP-II experts in progress
Tie-Rods
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 20 / 59
Revised RF Spring configuration
Double Wedge Adapters mountacross Tank ceiling & floor
2 RF springs mount to each Adapter
Jaw facet RF springs mount on Tank ceiling & floor
Shorter length springs also mount to
Tank ceiling & floor
Note: Jaw facet springs are wide enough for line contact thru full transverse travel range
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 21 / 59
Alternate Sheet Metal Transition configuration
NORMAL CONTACTS TO TANK CEILING & FLOOR
ROUND
RECTANGULAR
HOURGLASS
RETRACTED 22.5MM
Note: Not all Jaw facets are shown
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 22 / 59
BrazeTest #1 Cooling Tube
Jaw Center Mandrel
~100 mm
~70 mmdia
~100 mm dia
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 23 / 59
Aluminum Mandrel for Coil Winding Test and to test 3-axis CNC Mill before cutting 200mm and
950mm Copper Mandrels
200mm
Cooling Tube aligner
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 24 / 59
Development of Winding Tooling
Vise-Type Roller-Type
Aluminum Mandrel with Coil Wound
Test Winding the 200mm Copper Mandrel
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 25 / 59
Fabrication of Quarter Jaws for 2nd Braze Test
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 26 / 59
Final Wind of 200mm Copper Mandrel
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 27 / 59
First 200mm PrototypeBefore-After Brazing Coil to Mandrel
4 braze cycles were required before part deemed good enough to do jaw braze
Learned a lot about required tolerances of cooling coil and mandrel grooves
Pre-Coil-Braze
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 28 / 59
More Winding Tooling Developed
1m winding tooling Mill vise as precision bender
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 29 / 59
1mm raised shoulder (Hub) at center
Full Length Molybdenum Shaft
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 30 / 59
Braze Test#2 Delivered 19 Dec 2006
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 31 / 59
Vacuum Bake Test Results: 4/1/07
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.
Plan to discuss vacuum results with SLAC experts (Dan Wright) and to possibly incorporate vacuum pumpout drill holes into the design.
Next step: Sectioning & braze quality examination
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 32 / 59
Aluminum Test Mandrel with 80mm Gap for Downstream U-Bend (11/17/06)
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 33 / 59
Braze Test #3: 200mm Cu mandrel with U-Bend
Upstream end
Downstream end
Minor re-machining required to engage drive pins of coil
winding tooling
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 34 / 59
Tubing Wound and Tack Welded to Mandrel at the U-Bend
Note stub ends of cooling tube
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 35 / 59
Braze Test #3: Ready in Braze Lab for coil-mandrel braze
Next steps:
-Braze 8 quarter-round half-length jaws
-Vacuum test?
-Section & examine braze quality
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 36 / 59
Cut-away of Cu-Mo Hub CAD Model
#1 - Mandrel Dummy#2 - Mo Shaft Dummy#3 - Mo Backing Ring#4 - Cu Hub with braze wire grooves
#2#1
#3
#4
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
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 37 / 59
Cu-Mo Hub Braze Test parts
#1 - Mandrel Dummy (not shown)#2 - Mo Shaft Dummy#3 - Mo Backing Ring#4 - Cu Hub with braze wire grooves
#2
#3 #4
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 38 / 59
Sectioned Cu-Mo Hub Braze Test Assemblyafter 3 additional heat cycles to mimic full
assembly procedure
#1 - Mandrel Dummy#2 - Mo Shaft Dummy#3 - Mo Backing Ring#4 - Cu Hub
#2
#3 #4
#1
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 39 / 59
Moly-Cu Joint Declared “Good” by SLAC Braze Shop Experts, but…..
Small holes held braze wire
•Grain boundary issues?•Possible fracturing?
Samples being sliced & polished and sent to Physical Electronics lab for analysis
Cu-Mo joints we care about
1mm expansion gap
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 40 / 59
More Coil Tests Planned
• Twist a length of actual cross-section to failure for a measure of the margin of safety and maximum torque requirements.
• Bend samples of actual cross-section into required configurations.
• Section samples to inspect for internal distortion shapes and smoothness of transitions.
4-1/2 Turnswithout failure
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 41 / 59
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.
out of specification grooves
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 42 / 59
Up Beam Flex Mount Assembly components
Geneva Wheel & Actuator
(Ultimately, bearings will be ceramic; these steel)
SLAC Shops will fab first Universal Joint/Axle and Geneva Wheel Rotator Assembly by June 5
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 43 / 59
RF Contact Springs for Investigation
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 44 / 59
Main Steps Still Needed for Full Size Single JawFor Thermal-Mechanical Tests
After 200mm Jaw tests Completed Satisfactorily
– Jaw 1/4 sections (16 needed of 24 now at SLAC) require slight modifications for braze gap requirements.
– Moly shaft (at SLAC) will need to be cut in two pieces and brazed to copper hub
– Drill Cu mandrel for Moly Shaft
– Decide to use in-house SLAC Copper, or order our own (Finland 20 week delivery) or use CERN order of Ni-Cu alloy, anneal & wind mandrel
– Winding and Braze Cycles
– Drill jaw to accept resistive heater• Understand (ANSYS) any change to expected performance
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 45 / 59
Test Lab Preparation ~Finished
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 (!!!)
Adjacent 16.5 kW Chiller
Heater Power Supplies staged for installation in rack
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 46 / 59
Steps on Path to the Two Jaw Mechanical Prototype RC1
• Successful thermal performance of first full length jaw• Complete the design of RC1 RF features• Successful test of a working model of the Geneva wheel & universal joint• Fit-up and initial tests on 1st full length jaw• Complete fabrication of second jaw (Glidcop?, Moly??) with full support
assembly on the four corners• Remodeling of CERN parts for interface to US parts
– Models and assemblies of the various Collimator Mounting Stands are complete
– An enlarged vacuum tank has been modeled and some CERN support stand modifications have been identified
– No fabrication drawings have been done as yet• 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:
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 47 / 59
PLASTIC DEFORMATION of ENTIRE JAW after a BEAM ABORT ACCIDENT?
PRELIMINARY RESULT:– 0.27 MJ dumped in 200 ns into ANSYS model– Quasi steady state temperature dependent stress-strain
• bilinear isotropic hardening
– Result: • plastic deformation of 208 um after cooling, sagitta ~130um
– Jaw ends deflect toward beam
• Jaw surfaces at 90 to beam impact useable, flat within 5 um
Doyle
54 umBeam side
Far side Melted material removed
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 48 / 59
Boundary Conditions
During energy deposit (0 – 200 ns). All nodes (both ends) constrained in z
After energy deposit (200ns – 60 sec), z-constraints released. Original analysis used this constraint at all times.
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 49 / 59
Induced Activation of Secondary Phase II Collimators
Issue Raised by LARPAC Reviewers
Contact Dose Rate for Exposures at 4E9 p/s loss rate
1.00E+01
1.00E+02
1.00E+03
1.00E+04
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 1.E+08
Cooling Time (sec)
mS
v/h
r 30d
100d
1yr
20yr
1min 1hr 1d 1wk 1mo 1yr
Exposure
( t~1 day )
15 mSv/yr = max dose for rad worker at CERN
Work in progress by Mokhov et al
Have requested dose rate at ~1m
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 50 / 59
Inter-Lab Collaboration
Good will & cooperation limited only by busy work loads– Three video meetings since October 26, 2006 – Many technical exchanges via email– CERN FLUKA team modeling Rotatable Collimator– CERN Engineering team looking at SLAC solid-model of RC and
independently doing ANSYS calculations of thermal shock– CERN physicist
• investigating effects of Cu jaws at various settings on collimation efficiency• Participating in discussion of RF shielding design
– SLAC Participation in upcoming CERN Phase II brainstorming meeting– Ralph Assmann to visit SLAC in May/June 2007
Need to continue to pursue– Plan to bring a TCS assembly to SLAC – Plan to bring a spare support and mechanism to set gross x, y, u jaw
angles– Plans to understand scope and time scale of beam tests
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 51 / 59
Phase II – TCSM FLUKA Model @ CERNLuisella Lari
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 52 / 59
Extract from talk by Elias Metral Adressisg RF Concerns of SLAC Collimator Design
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 53 / 59
Collaboration on ANSYS Calculations of SLAC Design Performance and Damage
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 54 / 59
Collaboration on Tracking Efficiency StudiesChiara Bracco - CERN
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 55 / 59
Chiara’s (Frightening) Conclusions
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 56 / 59
CERN Collimation Plan & Schedule
0) Assume SLAC LARP develops Rotatable Collimator1) Develop TWO other complementary designs2) Develop a test stand for the three designs3) 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 R&D at SLAC (LARP) with CERN support.2006/7 Start of phase 2 collimator R&D at CERN.2008 Completion of three full phase 2 collimator prototypes at CERN and SLAC.
Prototype qualification in a 450 GeV beam test stand at CERN.2009 Installation of prototypes into the LHC and tests with LHC beam at 7 TeV.
Decision on phase 2 design and production.2010 Production of 36 phase 2 collimators.2011 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.
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 57 / 59
Summary of Progress since October 2006 Meeting
Design & Calculation– Mechanical design almost complete
• RF shielding concepts need finalization & testing– ANSYS calculations examining permanent deformation in case of
accidental beam abort complete
Fabrication– Fabricate and braze together a 2nd short (20cm) copper mandrel, cooling
tube and 4- quarter-round jaw pieces• Vacuum Bake test complete• To be sectioned & examined for braze quality
– Fabricate a 3rd mandrel with improved features & wind cooling coil• Await coil braze, 8-jaw braze, vacuum test, sectioning & examination
– Acquire first full length mandrel– Acquire first full length Molybdenum shaft
• Newest design will require it to be cut in half & brazed to a central copper hub– Moly-Copper test braze complete & subject to 4 braze cycles
• Visual checkout OK; await SEM analysis of Copper-Moly joint
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 58 / 59
LARP Collimator Delivery Schedule
Done Braze test #1 (short piece) & coil winding procedures/hardware
Prep heaters, chillers, measurement sensors & fixtures, DAQ & lab
Section Braze test #2 (200mm Cu) and examine –apply lessons
Braze test #3 (200mm Cu) – apply lessons learned
Fab/braze 930mm shaft, mandrel, coil & jaw pieces
2007-09-01 1st full length jaw ready for thermal tests
Fab 4 shaft supports with bearings & rotation mechanism
Fab 2nd 930mm jaw as above with final materials (Glidcop) and equip with rf features, cooling features, motors, etc.
Modify 1st jaw or fab a 3rd jaw identical to 2nd jaw, as above
Mount 2 jaws in vacuum vessel with external alignment features
2008-04-01 2 full length jaws with full motion control in vacuum tank available for mechanical & vacuum tests in all orientations (“RC1”)
Modify RC1 as required to meet requirements
2009-01-01 Final prototype (“RC2”) fully operational with final materials, LHC control system-compatible, prototype shipped to CERN to beam test
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 59 / 59
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 and completely tested RC1 device by end of FY07 and mid-FY08, respectively”
Jeff Smith (Ph.D., Cornell joins SLAC Collimation team ~July 1, 2007
Better project management needed on my part.
Need to incorporate schedule in CERN White Paper plan.
Extra Material Follows
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 61 / 59
Specification Changes Relative to April 2006 Design
RC1 Report 12/12/05 Current spec value value jaw Length 95cm including 10cm end tapers 93cm with 1cm end
tapers Diameter 136mm 20 facets, tangent to
136mm Material Copper Glidcop AL-15 cooling Embedded helical channel Reduced helix depth,
Helix pitch reversal Special features Circumferential slots to reduce
thermal-induced bending, if no RF problems
eliminated
deformation <25um toward beam; <325mm away in steady state; <750um away in 10 sec transient
Inward: 84um SS, 236um Trans – 1st coll to be set at 8.5 for clearance
Range of motion 25mm per jaw, including +/- 5mm beam location drift
27.5 mm per jaw including +/- 5mm
Aperture stop Range of motion Controls aperture from 5-15 sigma (2-6mm full aperture), must float +/- 5mm as jaws are moved to follow beam drift
eliminated
Heat load Steady state 11.3 kW 12.9kW Transient 56.5 kW 64.5kW RF contacts configuration Sheet metal parts subject to
CERN approval New geometry
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 62 / 59
Heat deposited in major components (W/m^3) in 1 hr beam lifetime operation
Component Units Upbeam Downbeam Stub shaft, aluminum W/m^3 6.5e3 52e3 Bearing, Si3N4 W/m^3 8.3e3 66.4e3 Image current bridge, aluminum W/m^3 150e3 400e3 Mo shaft (~const in z, concentrated in =120o) W 520 Jaw, Glidcop AL-15 (heat highly variable in z and ) kW 12.8
LARP Collab. Mtg. - 18 April 2007 Rotatable Collimators - T. MarkiewiczSlide n° 63 / 59
Major jaw dimensions and calculated cooling performance
Component dimension units Jaw OD tangent to 20-faceted surface 136 mm Jaw OD to facet vertices 137.7 mm Jaw ID 66 mm Jaw length, including 10mm (in z) x 15o taper on each end 930 mm Mo Shaft OD 64 mm Mo Shaft ID 44 mm Hub length (centered) 150 mm Cooling tube OD x ID (square x square) 10 x 7 mm Embedded helix – center radius 80 mm Helix – number of turns ~47 - Cooling tube length – helix + entry + exit from vac tank ~16 m Flow per jaw 9 l/min Velocity 3 m/s Water temperature rise (SS 12.8 kW per jaw) 20.3 C Pressure drop 2.4 bar