Why the vaccum presure has a limit of -760 mmHg. if we wants to create a vaccum pressure more than -760 mmHg what i can do means how i can create?
The vacuum pressure is limited to -760 mmHg, also known as a perfect vacuum or absolute vacuum, because it represents the theoretical absence of all gas molecules. At this level of vacuum, there are no remaining gas molecules or pressure exerted by any gas. However, it is possible to create a vacuum pressure lower than -760 mmHg by following certain techniques.
To create a vacuum pressure beyond -760 mmHg, you can use what is known as an ultra-high vacuum (UHV) system. UHV systems are specialized setups that employ advanced techniques to remove as many gas molecules as possible to achieve extremely low pressures.
Here are a few methods commonly used in UHV systems:
1. Pumping: Instead of relying on a single pump, UHV systems typically incorporate multiple pumps with higher efficiency, such as turbomolecular pumps or cryogenic pumps. These pumps can remove gas molecules more effectively and achieve lower pressures compared to regular vacuum pumps.
2. Surface treatments: Surfaces within the UHV system are often cleaned and treated to minimize gas adsorption or outgassing, which can contribute to pressure.
3. Bake-out: Heating the UHV system components can drive off any residual gas molecules that may be adsorbed to the surfaces, thus lowering the pressure further.
4. Cryogenic cooling: Cooling some components to extremely low temperatures can create a localized environment where certain gases will freeze out and reduce the overall pressure.
By combining these techniques and employing specialized equipment, it is possible to achieve vacuum pressures below -760 mmHg. However, it is important to note that achieving extremely low pressures requires a significant investment in equipment, expertise, and careful system design.