General Purpose Current Density Probe
This Faraday probe is well suited to current density measurements in both commercial plasma processing and electric propulsion environments.
This probe features largely graphite front-facing surfaces for minimum sputter contamination. Stainless steel components are available and can be substituted if the probe is to be heavily used in oxygen-rich environments.
The bare probe mounts using a single panel hole. This probe includes both the vertical and horizontal mounting brackets. Custom mounting alternatives are available for design and delivery at little additional cost.
Using the planar-style cap, the ceramic isolators allow the probe body to be used as a guard ring, typically biasing both the collector and body to the same negative potential relative to the plasma.
Planar Collector area: 0.5 cm2
Using the small-aperture cap, the probe body can still be biased negative, while the collector is biased less negative or positive to eliminate the collection of low energy charge exchange ions in some situations.
Aperture Diameter: 0.029 inches. Note that the aperture diameter can be easily enlarged using common drill bits.
Lead Time: Typically 4 weeks if not in stock.
The "Probe Only" option is the current density probe, having a BNC connector, and two mounting brackets.
The "Probe + Feedthrough + Cables" option includes the probe, a BNC-to-triax converter, in-vacuum and air-side teflon-based triax cables, and a double-ended triax feedthrough. By default, each cable is 10 feet (3 meters) long, and the triax feedthrough is mounted on a KF40 flange - we will confirm these options prior to assembly.
Note that a common BNC cable would carry the collector current on the center conductor, and the probe body bias on the sheath conductor. Using a standard BNC feedthrough for example, the sheath conductor and probe body would be tied to chamber (ground) at the feedthrough. Using a BNC-to-triax converter allows the inner sheath of the triax cable to carry the probe body bias, and the outer sheath of the triax cable to be tied to the chamber at the feedthrough.
Accessories: Plasma Controls can provide both in-vacuum and air-side BNC or triaxial cables at customer-specified lengths, as well as coaxial feedthroughs mounted on KF16, KF40, KF50, Conflat CF1.33, CF2.75, CF3.375, NASA 4.5"OD standard, or customer-specified flanges.