The circuit has an output filter consisting of a 100k resistor and a .22 uF capacitor and a typical experiment will have additional capacitance across the chamber, too. To get rid of the last bit of wander as the circuit pulses, increase the 100k to 10 megohm since ion chambers don’t draw significant current. I left the value lower in case this device is used to drive a heavier load and added an external 10 meghom in series with the output with a 10 uF polyester capacitor to ground right at the ion chamber. The load can’t be too heavy, however. This circuit can just barely drive a 22 megohm resistor with the full 110 volts and a 10 megohm multimeter will load it down to about 85 volts. The .22 uF will still bite you when it’s charged and a charged 10 uF will really get your attention! So be careful!
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