Pa Partial Pressure Research Articles

Development of master instruments for measuring total and partial pressures in high and ultrahigh vacuum regions

1. A master instrument has been developed, investigated, and certified for reproducing the unit of pressure in total and partial absolute pressure range of 10−3–10−11 Pa (total pressure) and 10−3–10−6 Pa (partial pressure). 2. The apparatus consists of the following master devices; the GRAD cryogenic master device of second class; OIM master ionization pressure gauge of third class; the OGIP master device of third class for calibrating partial pressure gauges; and the ORU-2 master pressure reduction device of the second class. 3. The characteristics of the instruments are given in Table 4. 4. The limiting pressure obtained with the GRAD cryostatic device is (3–4)·10−11 Pa; it is the lowest pressure ever obtained in a device of this type.