Replacing the Coldhead:
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- The coldhead can not be removed unless IGRINS is lifted above the leg height. This was achieved with reams of paper.
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- The cryostat lid can not be removed when IGRINS is lifted on paper reams. first remove the lid, then lift IGRINS to place paper reams underneath.
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- When lifting off the cryostat lid be careful not to bind on the pins. It helps a lot to release the wheel locks.
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- Removing the cold shield can be difficult because it is covered in tape. It requires about 6 hours of labor.
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- The cold shield sides are removed in a intersecting box (pinwheel) pattern.
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- To remove the coldhead you must first remove the getter.
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- Also, remove the copper plates as shown in photos.
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- (No photos–20241206)
- The coldhead drops out when specific fasteners are removed. Review photos to see which ones. Do not disassemble entire flange. support from the bottom.
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- Disassemble the coldhead flange, based on the photos, and replace all the o rings. Clean and degrease orings.
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- Lift the bellows from the bottom to avoid over stressing.
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- Lift the coldhead back into IGRINS and fasten into place.
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- Reconnect the copper strapping and charcoal box.
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- Done.
Items to be completed in the future (was this ever completed?--20241206):bake
- Bake getters annually
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- Slit mask needs more baffles