Charged particle beam generating apparatus
US5041732A · kind A · utility
19Cited by
5References
14Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1990 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Feb 21, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/06316
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a charged particle beam generating apparatus, the emitter is so arranged that its distal end is disposed at a level below a peak of a distribution of a magnetic flux density. An inner diameter of a lower portion of a pole piece is smaller than an inner diameter of an upper portion of the pole piece. The peak of the magnetic flux density is disposed close to the lower end of the pole piece, and at the same time the magnetic field is prevented from extending downwardly beyond the lower end of the pole piece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.