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)
有關真空和真空的單位 真空的質量與係統中剩餘粒子的數量有關。 氣體分子相互碰撞前的平均距離是真空級的特征
。通過泵送腔室來增加這個距離可以提高真空的質量
。 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.
