Principles & Protocols

Protocols - Using Carbon Thread in Edwards 306

Vent jar by pressing vent
- If "Vent" is not allowed (red light on key not lit), press "Start" then press Vent
When vented (2MB), remove jar by first disconnecting hinge, then lifting and rotating away
Secure carbon thread in holder (cut a ~4cm piece, place between screws and screw down)
Attach the holder to rod B&D and grounded rod 7cm from grid
Insert sample
If desired, fold a piece of filter paper and place near sample -- this will let you see the carbon shadow
Hold in place with microscope slide or pennies
Lower jar and press "Process"

Move stop over sample to prevent C from coating during step 10
Pump down to 10-4
Turn dial to #0 (L)
Switch LT selector to D (30V)
Switch on LT
Turn the selector up to # 2 to make the thread glow a few seconds and off gas contamination slowly
- if thread does not glow, his "Reset" button to allow current to flow
Remove stop to coat with C
Insert LN2 trap into hole on left side of pumping station. Trap is stored in drawer below station.
Add liquid nitrogen to the LN2 trap
Allow vacuum to recover to 5x10-6 - may need to be restarted
Trip the LT (this prevent current from flowing when you increase the current value in next step)
Set selector to 6
Press reset & look away
Thread will glow brightly until it burns out, leaving a thick layer of carbon on sample.
Turn off LT

7cm from grid and 1cm of thread gives about 6 nm carbon coat

This method is very reproducible

-- DavidStokes - 18 Mar 2005