when the field on the ion source region 60 side is substantially higher than the field in the ion funnel region 70 side many ions impact on the surface of the outer electrode 96 back deposition to overcome transmission losses due to this unfavorable field ratio a concurrent flow of gas can be added to prevent back deposition and thus maximize transmission of ions through the hte into the ion funnel region the device illustrated in fig4 a and b operates by generating ions or collecting ions in the ion source region 60 the ions are accelerated away from the ion source region toward and through the hte 90 into the funnel region 70 of the device where ions are focused through the funnel aperture into the deep well region where a well collimated and highly compressed beam of ions is delivered to the ion destination region 100 fig4 c displays the potential energy surface plot showing the relative potential of each component of the operating system in general the ions flow form a dispersive high field source region across the hte 90 with local high fields to nudge the ion through the openings and through the hte into and through the funnel shaped focusing fields of the funnel region 70 and into the deep.