- Freeze cotton leaves sample at -70 C in a deep freezer.
- Transport the sample in an ice chest box.
- Check to see that drain plug is closed (left side of condenser) and be sure that switch is off and ballast open.
- Turn on bottom switch of the condenser.
- Turn on top switches of chamber and set "shelf temperature control" to -400 or -50 C. Then, wait for chamber temperature to drop to set level (it usually takes 1 to 3 hr).
- Turn on bottom switch.
- Place the frozen samples on trays. Arrange in even layers. Placing second layer of tubes in bottom 2 trays is OK). It may be fun to place the probes into samples to watch the changing temperature.
- Close the chamber and wait for 1 to 2 minutes till the samples and chamber temperature equalize. During this time, ice crystals will coat metal parts of the chamber.
- Turn on switch and close ballast, and wait for vacuum to reach <100 mT (about 5 to 10 min). In the mean time, condenser temperature should be at least -40 C.
- Set "shelf temperature control" to -20 C and let run for 3 hr at least or overnight.
- Check the condenser periodically to be sure that the coil has not collected enough ice to lug it up (rarely a problem on a fresh run).
- After the run is complete, turn off switch and open ballast.
- Turn on and turn off vacuum switches simultaneously.
- Remove the samples and turn off top switches.
- Turn off switch.
- Close the cap of samples tightly immediately.
- Place samples in dry, air tight environment as soon as possible and store out of direct sunlight.
