FIELD-EMISSION ARRAY EXPERIMENTS RELEVANT TO COLD-CATHODE GYROTRONS

A collaboration between the University of Strathclyde and GEC-Marconi Ltd aims to develop an electron cyclotron maser/gyrotron using GEC-Mar coni Ltd silicon microelectronic field emission arrays (FEAs) as a col d cathode source. As part of this collaboration, novel sets of experim ents have been undertaken to show that the total I/V characteristics o f the FEAs are found not to be affected by vacuum recycling and transp ortation. Typical emission currents of 1 muA per tip were measured fro m multiple 100 tip arrays. Recent results of the emission current from a 30,000 tip array gave a total current of 16 mA measured at 80 V und er dc bias conditions. To represent gyrotron working conditions, I/V c haracteristics have been successfully obtained from FEAs in the presen ce of residual gases within the pressure range of 10(-10)-10(-7) mbar.