Method and apparatus for clearing ions in a scanning electron beam computed tomographic system using a single potential power source
US6208711A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 1999 |
| Grant date | Mar 27, 2001 |
| Priority date | — |
| Expiry date | Sep 21, 2019 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B6/4028
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
In a scanning electron beam CT system, a positive ion clearing electrode system is disposed within the CT system solenoid coil, and is operated from a single power source. Mounted coaxially about the electron beam, preferably the electrode system includes three sections, each having two electrode elements, one element being coupled to about -800 V to about -2 kV and the other element being grounded. Within the electrode system, the ratio between element diameter and electron beam diameter is substantially constant. Preferably elements are helically twisted about the beam axis. The electrode configuration cancels net quadrupole (focusing) and octopole (aberration-producing) fields. In the presence of electric discharge, essentially zero electron beam displacement and deflections occurs, and changes in focusing strength remain zero.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.