The ExB probe, also called a Wien filter, is a charged particle velocity filter, and can be used to measure charge-state downstream of an ion thruster, Hall-effect thruster, ion source, or other plasma device.
Ions enter the probe through a set of collimated apertures to limit the probe's field of view. The ions then enter a region that has both electric (E) and magnetic (B) fields, and experience forces according to the Lorentz equation F = q (E + v x B). For ions that have a particular velocity, where E = - (v x B), the net force is zero and those ions are able to pass through the crossed field region to a current detector.
Singly, doubly, and even triply-charged ions can be distinguished by sweeping the electric field and measuring the current to the on-axis collector. Data reduction then gives the double-to-single, or triple-to-single, ratio(s).
Lead Time: Typically 6 weeks if not in stock.
The "Probe Only" option is the ExB probe having a 6-pin connector carrying electrode biases and a triaxial connector carrying the collector current.
The "Probe + Feedthrough + Cables" option includes the probe, in-vacuum and air-side teflon-based cables, and double-ended 6-pin and triaxial feedthroughs. By default, each cable is 10 feet (3 meters) long, and the feedthroughs are mounted on KF40 flanges - we will confirm these options prior to assembly.
Accessories: Plasma Controls can provide both in-vacuum and air-side cables at customer-specified lengths, as well as feedthroughs mounted on KF16, KF40, KF50, Conflat CF1.33, CF2.75, CF3.375, NASA 4.5"OD standard, or customer-specified flanges.
The customer will typically need to provide a laboratory power supply (e.g. ~600 V at low current) and a sensitive electrometer/ammeter for measurements. Plasma Controls can provide custom quotes for this equipment and LabView or python-based software.
