DIFFUSION BLOCK FOR AN EVACUATED INSTRUMENT SYSTEM

One example includes an instrument system. The system includes instrument components at least partially disposed in an evacuated chamber within an instrument housing. The system also includes a barrier that is configured to seal the evacuated chamber. The barrier includes a plurality of instrument electrodes that are electrically coupled to the instrument components and extending through the barrier. The system further includes a diffusion block formed of a non-diffusive material and coupled to the instrument housing to seal an evacuated cavity within the instrument housing between the barrier and the diffusion block.