Pulsed field sample neutralization
US4968888A · kind A · utility
6Cited by
11References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1989 |
| Grant date | Nov 6, 1990 |
| Priority date | — |
| Expiry date | Jul 5, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2223/351
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method for alternating voltage and for varying the rate of extraction during the extraction of secondary particles, resulting in periods when either positive ions, or negative ions and electrons are extracted at varying rates. Using voltage with alternating charge during successive periods to extract particles from materials which accumulate charge opposite that being extracted causes accumulation of surface charge of opposite sign. Charge accumulation can then be adjusted to a ratio which maintains a balance of positive and negative charge emission, thus maintaining the charge neutrality of the sample.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.