Effects of ion pumping in a pulsed Penning source Available to Purchase

We recently reported on the first observation of ion-pumping phenomenon in a low-duty pulsed Penning source at the heavy-ion medical accelerator (HIMAC) in Chiba and its effectiveness to produce multiply charged ions [Y. Sato et al., Nucl. Instrum Methods Phys. Res. A 450, 231 (2000)]. In the Penning-ionized gauge ion source (PIGIS) of the HIMAC, the gas flow is not being pulsed, but there is a transient pressure response in the source when the arc is pulsed that permits the production of high-charge-state ions under a reasonably low gas pressure obtained by ion pumping. The best record for $Ar8+$ is 700 eμA in a peak under a constant gas flow of 0.2 cc/min, an extraction voltage of 24 kV, and a pulsed arc power of 1 kV and 5 A with a duty factor of 0.5% (25 W on average). This yield is higher than those of cw PIGISs by a factor of 100–1000 having a similar design and power (peak). This article gives a brief review for the mechanism and effects of ion pumping in a pulsed PIGIS.