Update on the VDC Rotator

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Update on the VDC Rotator
Dual VDC
VDC Rotator (WMJLab)

• Rotation and Translation
• ep profile position (IN)
• Parking position (OUT)

JLab beam line support
Dual VDC
downstream
upstream
2
Just another view w/o front wall and w/o
ceiling of detector hut
downstream
upstream
3
Rotator current status

• September invitation for sealed bids sent out
• Oct 31 BL Machining in Norfolk awarded contract
  by WM Procurement. 89,025
• original estimate (Jlab engineering 30K
  MRI budget, incl. contingency 50K)
• WM purchased nuts, bolts, rods, rollers etc.
  3k
• All parts cut machined to size
• Welding starts next week
• Meeting/Inspection with Paulo Medeiros and WM
  for welding process
• Anticipated Rotator ready to ship to JLab
  mid/late March

Upcoming Rotator at JLab

• Allocate space in Test Lab
• (Re)Assemble the rotator
• Needs JLab manpower and equipment
• Needs G0 rails
• Needs beam support structure for rotation tests

Rotator offline commissioning (outside of Hall C)

• Or How precisely can we rotate and radially move
  
• and lock the wire chambers into position ?
• Needs mockup wire chamber for the load

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BL Machining Current Status
(Monday, January 29, 2007)
V-Grooved Load Runner
4 Steel Half-Rings

• Machining the V-Groove will be done after
  assembly at BL

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BL Machining Current Status
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Locking the rotation angle

• Remote locking at one octant by inserting/
• retracting a precision dowel pin into one of
• the 8 holes drilled into the upstream SS ring
• Hole diameter 1.004
• Dowel pin diameter 1.000
• Rotator will be rotated with a large chain
• driven by a motor with a small driving gear
• Optional Use a break pad system as
• a safety feature

4mil 101.6 µm
Upstream SS Ring
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Locking the radial position

• Rotate the VDCs horizontally
• Use pneumatic system to move the two arms from
• parking position into final radial
  position
• Lock the positions with two precision dowel pins
  per arm
• Hole diameter 1.004
• Dowel pin diameter 1.000

(4mil 101.6 µm)
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Alignment of Region 3

• Rotator should be fiducialized before
• the detector hut is built
• Establish fiducialized reference system
• within detector hut ?
• - mount optical targets on inner wall ?
• - leave viewholes open to Hall C
• reference markers ?
• Since the Rotator/Region 3 is relative to
• the beam line support
• Will there be a sagging of the floor
• due to extra load of
• - lead shielded beam line
• - concrete walls ?

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JLab Survey Alignment Group
Contact Person Chris Curtis
FARO Laser Tracker - Absolute Distance
Measurement Accuracy 10um 0.4um/m
Resolution 0.5um - Interferometer
Accuracy 2um 0.4um/m
Resolution 0.158 um Range up to 70m
Theodolite - Accuracy 0.25mm ?! (on
extended object size)