nonUHV

NonUHV is a term used in vacuum technology to describe vacuum conditions that do not meet ultrahigh vacuum (UHV) standards. UHV is typically defined as pressures well below 10^-7 to 10^-9 mbar, depending on the reference. nonUHV encompasses vacuum regimes with higher pressures, including high vacuum and rough vacuum, and can also cover environments approaching atmospheric pressure in certain vessels. The label is practical, signaling that processes may tolerate more contamination, higher outgassing, and simpler materials than UHV requires.

Pressure ranges and measurement: nonUHV regimes generally lie above the UHV threshold, from around 10^-3 mbar up to near atmospheric, depending on the system and application. Measurements employ gauges appropriate for these pressures, such as Pirani, thermocouple, or ion gauges in different subranges. Pumping technology includes rotary-vane pumps, dry scroll pumps, turbo pumps, and backing pumps that establish the necessary pressure but do not necessarily reach UHV levels.

Applications and considerations: nonUHV is common in industrial coating, material processing, packaging, and some analytical or manufacturing environments where ultra-clean conditions are not required or impractical. Surfaces processed under nonUHV may form oxides or adsorb gases more readily than in UHV, so surface preparation and materials selection emphasize practicality and cost. In research, nonUHV experiments can still yield valuable data on gas-surface interactions, but they do not support the extreme cleanliness and low contamination levels characteristic of UHV techniques.

See also vacuum technology, high vacuum, ultrahigh vacuum.