A hot cathode magnetron gauge using a divergence-type magnetic field for electric field control

A new sensitive type of magnetron gauge has been developed in order to obtain a linear response of ion current, I-i, to pressure, P, with a high sensitivity over a wide range. The gauge is equipped with two ion collectors. The ratio of the ion currents of the two ion collectors is measured and kept constant by controlling the filament voltage, in order to keep the electric field constant within the anode over a wide range of pressure measurement. When a divergent-magnetic field is applied to this hot-cathode magnetron gauge, the slope of the plot of the filament voltage vs the ratio of the ion current of the two separate two ion collectors is improved from -0.28 to +1.1- + 3.9 (V-1). When the diameters of the ion collectors were investigated, it was found that the current ratio eta = 1 was attained when the outer diameters of the ion collectors were identical, and their inner diameters were 2 and 8 turn respectively. With this configuration, ion current was directly proportional to pressure in the range of 1 x 10(-8)-1 x 10(-4) Pa.