Reply To: Boron availability

[pulser]

Kapton is good for vacuum systems, but as mentioned will break down over time. Use 4x the thickness associated with dielectric strength for long term reliability.
Dealing with high voltages can be challenging. Use of semi-insulators will help with limiting electrostatic charge build-up and localized breakdown. I’ve found most people are not familiar with semi-insulators and the concept of what they do and how to use them is challenging even for electrical engineers working with high voltage devices for a living. Semi-insulators include materials like SIPOS and silicon rich silicon nitride (more like amorphous silicon than Si3N4). Carbon could also be used but I have no experience on the best form or deposition methods. Sheet resistances of 1e12 to 1e15ohms/sq are typical. Using alternating layers of semi-insulators and high dielectric strength insulators is a very good way to stand off very high fields even with ionization taking place creating localized high field spots. For pulsed applications such as this, much higher conductivity films could be utilized as long as the power dissipation does not cause significant self heating.