Electron multiplier for X=ray imaging tube - has multiplying elements which subtend angle w.r.t. axis of appts. which is proportional to element-axis spacing

摘要

The appts. is used for focussing electrons and is operated in the space of an electronic optic of a photocathode image inverter tube. A number of multiplier elements (4) are distributed about an axis (10), such that the elements converge radially towards a focal point (F). Elements of an outer ring may converge towards a focal point nearer the multiplier than successive inner ring elements. Electrons entering the multiplier generate more electrons which are directed towards the focal point or points by virtue of the element orientation. One or both faces of the multiplier may be perpendicular to the axis (10) or the output face may be part spherical. The multiplier may be constructed with a number of parallel sheet electrode elements each pierced with a number of holes which are aligned in sets along axes converging at the focal point.