Vacuülniveau

Vacuülniveau describes the degree to which a closed space has been evacuated of air and other gases. In vacuum technology, the level is expressed as a pressure value and is typically categorized into rough (low), medium, high, and ultrahigh vacuum, corresponding to progressively lower pressures. Common units for reporting vacuum include pascal (Pa), millibar (mbar), and torr; 1 atmosphere equals 101,325 Pa and 760 Torr. The choice of unit often depends on the field and the measurement range.

Measurement and instrumentation

Vacuum levels are measured with various gauges chosen for different pressure ranges. Pirani gauges measure thermal conductivity and are suitable for rough to medium vacuum. Penning (cold cathode) gauges extend measurement into lower pressures. Ionization gauges (hot or cold cathode) are used for high to ultrahigh vacuum, providing sensitivity at very low pressures. Capacitance manometers offer accurate pressure readings at higher vacuum levels and are preferred when precise absolute pressure is required. Gauges may be calibrated for specific gases, and many systems use multiple gauges to cover the full range of operation.

Causes and maintenance

Maintaining a desired vacuüm level requires controlling leaks, outgassing from materials, and gas loads from pumps and surfaces. Temperature, chamber design, and the choice of pumping system influence achievable vacuum. Common pump combinations include rotary vane or dry pumps for rough vacuum, turbomolecular or diffusion pumps for higher levels, and ion pumps or getter pumps for ultrahigh vacuum.

Applications

Vacuülniveau is critical in semiconductor manufacturing, thin-film deposition, surface science, mass spectrometry, cryogenics, and electron or ion beam instruments. Accurate vacuum control ensures process conditions, measurement accuracy, and equipment performance. The term is primarily used in Dutch-speaking contexts and in international technical literature dealing with vacuum technology.