any user may operated the tool up to 30 keV maximum the FE-Gun has reach optimal brightness and stability in its emission. Gun vacuum mid E -010 torr and stable during this test 20 kev beam I 20 um aperture = 0.1527 nA 30 kev beam I 20 um aperture = 0.230 nA 20 kv qualification write in progress... JWC