The energy E, the frequency n, and the wavelength λ of a
photon are related by:
E = hν = hc/λ
Electron Volt conversion: E (eV) = 1240/ λ (nm)
有关真空和真空的单位 真空的质量与系统中剩余粒子的数量有关。 气体分子相互碰撞前的平均距离是真空级的特征 。通过泵送腔室来增加这个距离可以提高真空的质量 。 Pressure
The International System of Units (SI) of the pressure is the Pascal (Pa), equal to a force of 1 N/m2, but the CGS unit called Bar (bar) is largely employed, too. The vacuum pressure can also be measured in torrs (Torr) or in atmospheres (Atm). For conversions, professionals prefer to use units such as millibars (mbar) and hectoPascal (hPa) which are the easiest way to convert those units in torrs with an approximate factor. The below approximations for the unit conversion is commonly accepted. Vacuum range
Low (rough) vacuum Atmospheric pressure to 1 mbar
Medium vacuum 1 to 10-3 mbar
High vacuum (HV) 10-3 to 10-8 mbar
Ultrahigh vacuum (UHV) 10-8 to 10-12 mbar
Extreme High vacuum (EHV) Less than 10-12 mbar
Fig. 2: High vacuum (HV)A level of the High Vacuum of about 10-5 to 10-6 mbar (10-3 to 10-4 Pa) is sufficient for most of the VUV applications applied for deposition of thin films, semiconductors, most of the characterizations by reflectance or absorbance methods, and spectral emissions … where a none strict vacuum is targeted, leaving free passage of light, particles and electrons.
Fig. 3: Ultra high vacuum (UHV)
The Ultra High Vacuum is more dedicated to the research domains, such as fusion studies, electron sciences, Free Electron Lasers or Synchrotrons, where contaminations with molecules of residual gas may be an issue in the experiments are good examples.
