vacuumrelated

Vacuum-related topics encompass conditions, technologies, and applications involving vacuums, environments in which the pressure is substantially below atmospheric pressure. The term covers the physics of gases at low density, the generation and control of evacuated spaces, and the processes and devices used to create and maintain those environments. It also includes historical developments such as vacuum tubes and modern applications in science and industry.

Vacuum levels are described by pressure ranges that span several orders of magnitude. Rough or low vacuums extend from atmospheric pressure down to about 1 Torr (approximately 133 Pa). High vacuum refers to pressures below about 10^-3 Torr (roughly 0.13 Pa), and ultra-high vacuum covers pressures below 10^-7 Torr (about 10^-5 Pa) and lower. Vacuum systems employ various pumps, such as rotary vane and diaphragm pumps for initial roughing, turbomolecular and diffusion pumps for higher vacuums, and ion pumps for ultra-high vacuum. Pressure is measured with gauges including Pirani, cold cathode or hot cathode ionization gauges, and Penning gauges.

Applications of vacuum technology span science and industry. In manufacturing, vacuum environments enable thin-film deposition, such as physical and chemical vapor deposition, and contamination-free coating processes. In research, vacuum chambers support surface science studies, electron microscopy, and mass spectrometry, where collisions with air must be minimized. Vacuum is also crucial in space simulation, vacuum packaging, and historical electronics involving vacuum tubes. Key challenges include outgassing from materials, maintaining seals, leaks, and maintaining cleanliness to achieve and sustain desired pressures.