PUMPING SPEED OF GETTER-ION PUMPS AT LOW PRESSURES,
Abstract
Pumping speeds of commercial diode and triode type getter-ion pumps were measured for the gases H2, He, and N2 over the pressure range from about 10 to the minus 11th power Torr to 0.000001 Torr. At 10 to the minus 10th power Torr, the pumping speed was 15-25% of the speed at 0.000001 Torr where the pumps attained the rated speed. Pumping speed measurements as a function of time showed that the pumping speed decreased generally only slightly over a period of one day. Strong saturation was found only for He at pressures above 10 to the minus 7th power Torr. No significant difference between diode and triode in the pumping speed vs. time or vs. pressure curves was observed. In the diode, pump currents were measured. The quantity P.S/I (P = pressure, S = pumping speed, and I = current) was found to be pressure independent for short pumping times. The numbers (in molecules or atoms pumped per charge) are: 0.5 (H2), 0.6 (He), and 0.2 (N2). (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1966
- Accession Number
- AD0634594
Entities
People
- Andras Dallos
- Fortunat Steinrisser
Organizations
- University of Illinois Urbana–Champaign