Electron source and electron beam device using the same

An electron source comprising:

• a filament made of a metal;
• a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery;
• a graphite sheet or rhenium foil disposed inside the metal tube;
• and
• a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is in contact with the graphite sheet or rhenium foil disposed at the bottom of each of the plurality of recesses of the metal tube.

An electron source comprising:

• a filament made of a metal;
• a metal tube that is fixed to the filament and has a plurality of recesses disposed at least in two axial directions so as to surround a central axis at an outer periphery;
• and
• a columnar hexaboride tip that emits an electron, is disposed so as to protrude from the inside of the metal tube to a side opposite to the filament, and is coated with glassy carbon or a mixture of glassy carbon and boride carbon and is in contact with the plurality of recesses of the metal tube.