Vertical Test Facility

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Vertical Test Facility
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Radiation Shielding

• Shielding is provided by a movable shielding box
  which is placed over the vertical dewar. 
• Shielding box is about 1 foot thick, and is
  composed of lead bricks surrounded by about 1
  inch of steel plate. 
• The shielding box is moved on rails with a
  control similar to the high-bay roll-up door. 
  The end with the instrumentation and controls is
  fixed. 
• The wires and piping are passed through a
  labyrinth in the lead bricks in the false floor. 
  
• The position of the shielding box is interlocked
  in the personnel safety system.

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Vertical test dewars (3/6 shown) with movable
blue radiation shields
Shielding is 1 foot thick, composed of lead
bricks with 1 inch steel plate
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Radiation shielding moves along rails, controlled
with buttons like high-bay roll door
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Note shielding mates when closed no cracks
Movement control switches
Cables run through a labyrinth in the lead
shielding bricks in false floor
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Magnetic switches indicate radiation shield
closed/open Interlocked personnel safety system
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Moving a cavity to VTF

• Cavities (or cavity strings) are fabricated, then
  cleaned and sealed at the ends in class 10 and
  class 100 clean rooms.
• Cavities are moved to the vertical assembly area.
  No attempt is made to keep the outside of the
  cavities clean. The helium vessels are not
  cleaned.
• The assembly area is separated from the outside
  by plastic-flap walls.
• Inside the assembly area, the outer attachments
  are made and warm tests performed.
• The roof of the assembly area is a mezzanine
  containing the top of a vertical test dewar with
  instrumentation.
• Using a crane, the completed assembly is lifted
  up through the roof and over to a vertical test
  dewar in the VTF.

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Inside the VTF assembly area
Two assemblies shown
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The roof of the assembly area contains the top
plates of vertical dewars and instrumentation
The assemblies are lifted up through the
mezzanine floor (assembly area roof) and over to
the VTF
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VTF Magnetic Shielding

• Room temperature magnetic shielding AD-MU-80 (80
  Ni) outside vertical test dewar (B)
• Dewar surrounded by giant solenoidal windings
  (current 7.34 A) to buck out external field (BT).
• External field B 3-4 G reduced to 5-10 mG
• No monitoring of magnetic field in dewar
• Solenoidal coil current monitored/interlocked