Fundamentals of Physics Part 4 Creating a Vacuum

Fundamentals of Physics

4) Creating a Vacuum

For centuries scientists have been trying to create lower and lower temperatures and pressures, initially by evacuating gas from containers with mechanical pumps.

But today more refined technologies such as diffusion, ionisation, chemisorption etc. are used to produce ‘high’ partial vacuums for commercial and experimental use and it is possible to (momentarily) achieve extremely low pressures, termed as ultra-high vacuums (UHV), to within a fraction of absolute zero pressure and temperature.

Ultra-high vacuum is vacuum regime characterised by pressures lower than about 10 pascal or 100 nanopascals (10 mbar, ~10torr). (Wikipedia)

But there is no single vacuum pump that can operate all the way from atmospheric pressure to ultra-high vacuum. Instead, a series of different pumps is used, according to the appropriate pressure range for each pump. High pumping speeds are necessary and multiple vacuum pumps are used in series and/or parallel.

Pumps commonly used in combination to achieve UHV include:-

1) Turbomolecular pumps (especially compound and/or magnetic bearing types)

2) Ion pumps

3) Titanium sublimation pumps

4) Non-evaporable getter (NEG) pumps

5) Cryopumps

But the UHV’s produced cannot be sustained for any length of time, this is due to contamination of the sample resulting from such effects as ‘out-gassing’.

Out-gassing can include sublimation and evaporation, which are phase transitions of a solid or liquid substance into a gas, in other words at these extremely low conditions of pressure, atoms, either contained within, or vapourised from the surfaces of, the solid matter of the apparatus are drawn into the volume under examination.

Out-gassing is a significant problem for UHV systems. Out-gassing can occur from two sources: surfaces and bulk materials. Out-gassing from bulk materials is minimized by careful selection of materials with low vapor pressures (such as glass, stainless steel, and ceramics) for everything inside the system. Hydrogen and carbon monoxide are the most common background gases in a well-designed UHV system. Both Hydrogen and CO diffuse out from the grain boundaries in stainless steel and Helium can diffuse through steel and glass from the outside air.” (Wikipedia)

And extraordinary preparatory steps are required to reduce these effects, which include the following:-

1) Baking the system (for one-two days at up to 400°C while the pumps are running) to remove water or hydrocarbons adsorbed to the walls.

2) Minimizing the surface area in the chamber.

3) High conductance tubing to pumps — short and fat, without obstruction.

4) Low out-gassing materials such as certain stainless steels.

5) Avoiding creating pits of trapped gas behind bolts, welding voids, etc.

6) Electropolishing all metal parts after machining or welding.

7) Low vapor pressure materials (ceramics, glass, metals, and teflon if unbaked).

8) Chilling chamber walls to cryogenic temperatures during use.

9) Avoid all traces of hydrocarbons, including skin oils in a fingerprint.

These preparatory requirements, together with the actual pumping processes, use an enormous amount of energy and, as it is not technically possible to completely eliminate out-gassing or other contaminating efflux, these very low pressures, or conditions, cannot be sustained for any length of time, it is therefore clear that there is a progressively increasing force of resistance to the decompression of a gas, and a very strong resistance to the maintenance of such levels of pressure.

Why should this be the case when the only external resistance is that generated by atmospheric pressure, which in theory should be easily overcome by modern machinery?

In the opposite direction, for example, there are sophisticated machines in regular use today that compress materials to upwards of 200,000 times atmospheric pressure, for example to produce industrial diamond from carbon.

This high level of resistance requires an explanation.

It is a core premise of currently accepted physics theory that a perfect vacuum cannot influence matter in any way, and accordingly nor can any of its hypothetical, aetherial constituents.

This being the case, the question is:-

What forces are operating in these circumstances to prevent the extraction of all matter from within the compartment, and what is the source of this resistance?

The simple diagram below illustrates this situation with a perfectly sealed piston cylinder apparatus, and a single atom within the cylinder.

The hypothetical, non-material, empty space which is believed to occupy virtually all the chamber, by definition, can have no influence and, as matter is undeniably present within the compartmental space under investigation (and in the surrounding structure), it can only be either the single atom, and/or the atomic structure of the apparatus which generates this exponentially increasing resistance.

In other words it is matter, and matter alone, that is the cause of this resistance.

As mentioned earlier, today it is being said that the vacuum is not empty, but is permeated with waves of energy, etc. etc., but again such a medium has to have the qualities of non-resistance to the free motion of atoms and molecules within it (i.e. is a zero-inertia medium) and so could not generate any resistance.

But, in terms of the kinetic atomic theory of gases, where the only force allowed is a positive one generated by the collisions of atoms, the generation of such a resistive or negative force is inexplicable, and if the matter of our experience is almost entirely composed of a non-material ’empty space’ (of any speculative description) then, technically speaking, it should be very easy to remove all atoms from within it.

It is an undeniable fact that current physics theory has no answer to this question and, as these numerous empirical results are a direct falsification of current, kinetic-atomic atomic theory of gases, it would be accordingly necessary to conclude that this, the base theory of the science of physics, is invalid.

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