vacuümmeters

A vacuum meter, or vacuum gauge, is a device used to measure the pressure inside a vacuum system. Vacuum meters are essential in research and industry for processes that require low ambient pressure, such as electron microscopy, thin-film deposition, semiconductor manufacturing, and cryogenic experiments. Readings are typically reported in units such as pascals, millibars, torr, or micrometers of mercury, and may cover a broad range from near atmospheric pressure to ultra-high vacuum levels.

Vacuum meters are categorized by their measurement principle and the vacuum range they are designed to cover. Thermal-conductivity gauges, including Pirani and thermocouple gauges, infer pressure from the rate at which a heated element loses heat to the surrounding gas, and are commonly used for rough to medium vacuum. Ionization gauges, such as hot-cathode Bayard-Alpert and cold-cathode Penning types, measure pressure by detecting ions produced when residual gas molecules are ionized, and are used for high and ultra-high vacuum. Capacitance diaphragm gauges determine pressure from the deflection of a flexible diaphragm and provide accurate readings in the high to medium vacuum range. In many systems, multiple gauges of different types are used to cover the full range.

Other considerations include the distinction between absolute and gauge readings. Many vacuum gauges measure gauge pressure (relative to atmospheric pressure), while some provide absolute pressure. Readings can be gas-dependent, and gauges require calibration against standards. Maintenance and proper venting are important to prevent contamination, gas loading, or damage to sensitive gauges, especially in ultra-high-vacuum applications.