Long life mammography x-ray tube, with high emission current, has a thermionic cathode

摘要

A mammography x-ray tube has a thermionic cathode with an emissive layer of very small particles (VSPs) containing tungsten, barium oxide, calcium oxide and an oxidic scandium compound. A mammography x-ray tube has a thermionic cathode comprising a substrate bearing an emissive layer of 1-100 nm mean diameter particles containing tungsten, barium oxide, calcium oxide and an oxidic scandium compound. Preferred Features: The oxidic scandium compound is Sc2O3 or Sc2W3O12.