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Chemistry building

Using the Plasma Reactor

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The Plasma Reactor can be used to form an oxygen plasma for cleaning gold electrode surfaces. The general procedure is detailed below with a rough sketch of the reactor itself. The reactor can also be used to oxidise the gold surface or to form polymers on a surface (the monomeric unit being introduced via the Youngs Flask).

Plasma Reactor wide view

Oxygen is introduced into an evacuator reaction chamber at a low flowrate. An induction coil (in blue) is used to "ignite" the plasma.


Standard Operating Procedure for cleaning electrodes:

1) Close the Large Vent (on left, going to high-vacuum pump).

2) Open the Small Vent to vent system.

3) Unscrew Right-hand Steel Plate.

4) Turn on Coaxial Power System (at back), allow ~1 minute to power up. Ensure steel switch at back is down - CW (Continuous Wave) position

5) Load samples onto glass plate.

6) Replace Right-hand Steel Plate.

7) Close Small Vent.

8) Open Large Vent.

9) Allow to pump down until vacuum is less than 10x10-3 mbar.

10) Open oxygen cylinder at cylinder head.

11) Open oxygen valve until pressure = 1 mbar.

12) Turn GEC-Marconi regulator until oxygen flow rate = 40.

13) Open Inlet Valve, adjust until pressure = 1x10-1 mbar.

14) Switch off fume cupboard light.

15) Press RF ON.

16) Turn Output Set dial until INCIDENT = 50.

17) Use LOAD and TUNE dials, until REFLECTED = 0.

18) NB. Plasma should be "spectral blue" (O2 plasma) NOT pink. If pink reduce O2 flowrate.

19) Wait 30 minutes.

20) Press RF OFF.

21) Turn Power System off at back.

22)Turn Output Set anticlockwise until it cannot turn any further.

23) Close all valves on oxygen cylinder.

24) Close Flowmeter valve.

25) Close Inlet Valve.

26) Close Large Vent to isolate from pump.

27) Open Small Vent to release vacuum.

28) Reset vacuum gauge by switching on and off.

29) Unscrew Right-hand Steel plate and remove samples.

30) Replace plate, close Small Vent and open Large Vent - system should be under vacuum when not in use.

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