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#1
Seal 10mm ID - 12mm OD trubore tubing to 500ml round bottom flask. Seal 16mm OD tubing to top side of flask. After flame annealing, this tube will be cut at 3/4". |
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#2
Seal 10mm OD tubing to 1 liter round bottom. On opposite end, seal 2 1/2" of 14mm ID - 16mm OD trubore tubing. To this, seal 4" of 41mm OD tubing. Blow slight buldge on top side of flask to accommodate fill port. Oven anneal. |
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 | #3
After annealing, score and hot crack 1 liter flask. Cut 41mm tube just past the shoulder. Carefully wrap uncoated copper wire around 12mm OD trubore. Insert this through 16mm trubore. A proper fit is achieved when the wire just fits, holding the two tubes tightly and concentrically. Align the fill port with the buldge and secure bottom of 1 liter flask with masking tape. |
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 | #4
Seal 24/40 female joint to 12mm inside tube. Take care that the tube and joint rotate on the same axis before sealing. A dog leg here will render the dewar useless.
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 | #5
Slide a short length of 41mm tubing over the 24/40 female and fix with masking tape at the back side. Make a quick dewar seal, remove tape and seal at shoulder. Add 8mm side arm and flame anneal. Remove masking tape from 1 liter bulb and reseal it. Make ring seal for fill port and add 19/22 female to complete it. Flame anneal and then oven anneal.
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 | #6
Removal of the copper is accomplished by filling the dewar with a mixture of aqua regia (1 part HNO3 - 3 parts HCL). This operation must be done in a fume hood. Once the copper is dissolved, drain and rinse with distilled water. |
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 | #7Silvering is accomplished in 2 steps. First with the dewar held as shown, silver up to the ring seal. Invert and silver to shoulder of 41mm and 16mm.
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 | #8
Completed dewar is shown potted to metal base along side copper sample holder. Capillary sample is held in cut out section of rod. Rod is lowered into LN2 to freeze sample. Sample is held concentrically in viewing area and analyzed by laser. |
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