Metal anodes in high power microwave (HPM) devices Erode during operation due to hydrogen outgassing and plasma formation; both of which are thermally driven phenomena generated by the electron beam impacting the anode's surface. This limits the lowest achievable pressure in an HPM device, which reduces its efficiency. Laser surface melting the 304 stainless steel anodes by a continuous wave fiber laser showed a reduction in hydrogen outgassing by a factor of ∼4 under 50 keV electron bombardment, compared to that from untreated stainless steel. This is attributed to an increase in the grain size (from 40 - 3516 μm2), which effectively reduces the number of characterized grain boundaries that serve as hydrogen trapping sites, making such laser treated metals excellent candidates for use in HPM applications
