Tyhjiömittaus

Tyhjiömittaus refers to the measurement of pressure within a vacuum. A vacuum is a space devoid of matter, but in practical terms, it refers to a space where the pressure is significantly lower than atmospheric pressure. The determination of this low pressure is crucial in various scientific and industrial applications, including semiconductor manufacturing, scientific research, and food packaging.

Various instruments, known as vacuum gauges, are employed for tyhjiömittaus. The choice of gauge depends on the specific pressure range and the required accuracy. For instance, Pirani gauges are commonly used for medium vacuum ranges, while ion gauges are suitable for ultra-high vacuum measurements. Capacitance manometers offer high accuracy and are often used for calibrating other vacuum gauges.

The units of pressure used in tyhjiömittaus include Pascals (Pa), Torr, and millibar (mbar). Atmospheric pressure at sea level is approximately 101,325 Pa, 760 Torr, or 1013.25 mbar. As pressure decreases, it enters the vacuum regime. Understanding and accurately measuring these low pressures is fundamental to processes that require controlled environments free from atmospheric contamination or where specific physical phenomena only occur under reduced pressure.