Positron source

A positron source for production of an intense positron beam with a small energy bandwidth, comprising:

• a positron emitter of high specific activity, and
• a reflection moderator arranged in front of said positron emitter,
• wherein said reflection moderator has a hole with a diameter of less than 0.4 mm on its side directed to said positron emitter, and
• wherein said hole through said reflection moderator is conical and has a smaller diameter on said emitter side than on its side remote from said positron emitter.

A positron source for production of an intense positron beam with a small energy bandwidth, comprising:

• a positron emitter of high specific activity,
• a reflection moderator arranged in front of said positron emitter,
• a support to which said positron emitter is applied, and
• a first adjusting unit for positioning said positron emitter in three spatial directions relative to said reflection moderator,
• wherein said reflection moderator has a hole with a diameter of less than 0.4 mm on its side directed to said positron emitter.

The combination of a positron source for production of an intense positron beam with a small energy bandwidth, comprising:

• a positron emitter of high specific activity,
• a reflection moderator arranged in front of said positron emitter,
• an electron microscope with an electron source and a magnetic prism for superimposing an electron beam coming from said electron source and a positron beam coming from said positron source,
• a respective double deflecting system and a respective magnetic lens following said double deflecting system for focusing said positron beam and said electron beam onto an image plane of said magnetic prism, and
• a further deflecting system positioned in advance of said magnetic prism, in at least one of said positron beam and said electron beam,
• wherein said reflection moderator has a hole with a diameter of less than 0.4 mm on its side directed to said positron emitter.