Charge-carrier extraction from air and nitrogen gas streams that entrain charge from a radioactive ionizer

Abstract Charge decay upon a pre-charged target was studied in a gas flow channel that contained a 210 Po ionizer. Unlike electrical corona, the radioactive ionizer produced positive and negative charge-carrier pairs in the absence of an external electric field. The initial charge extraction currents I ce for a negative target in nitrogen and positive/negative target in air were approximately the same. The I ce for the positive target in nitrogen was significantly higher due to the higher negative carrier mobility in nitrogen. Exponential dependences of I ce on temperature were very similar in both gases. The steady state residual potential on the target was zero in the temperature ranges tested.