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Below are some of the slides contained in this video.

Operation Ranges of Vacuum Pumps

  • Mechanical Pumps: atmospheric – 10-2 Torr
  • Sorption (Adsorption) Pumps: atmospheric – 10-3 Torr
  • Molecular Drag Pumps: 1 – 10-2 Torr
  • Turbomolecular Pump: 10-2 – 10-8 Torr
  • Diffusion Pump: 10-3 – 10-7 Torr
  • Cryopump: 10-3 – 10-8 Torr

Mechanical Pump

Slide titled 'Mechanical Pump' showing diagrams of Oil Sealed and Dry Mechanical Pumps. The left diagram illustrates a cross-sectional view of an oil-sealed mechanical pump, highlighting the gas flow path. The right side displays three types of dry mechanical pumps: a Lobe (Roots) pump, a Rotary Vane pump, and a Claw pump. Each pump type is depicted with annotations indicating the gas flow direction and key components like the rotor, vane, spring, oil seal, and swept volume. The source of the diagrams is credited to Donald M. Mattox's 'Handbook of Physical Vapor Deposition (PVD) Processing, 1998'.

Turbo-Molecular Pump

Slide titled 'Turbo-Molecular Pump' featuring diagrams of a high vacuum turbo-molecular pump. The left diagram illustrates a detailed cross-sectional view showing the rotor levels, vanes, vacuum side, and exhaust. The central image presents a 3D cutaway view of the turbo-molecular pump, highlighting the internal structure and gas flow path. The right diagram depicts a side view of the pump, focusing on the mechanical components. The source of the diagrams is credited to Donald M. Mattox's 'Handbook of Physical Vapor Deposition (PVD) Processing, 1998'.


  • Consists of a vacuum-tight vessel with a valved inlet, containing a highly absorbent material such as a synthetic zeolite microporous on the scale of 1 to 10 A and an enclosing cryogenic vessel.
  • Compressed helium is used to cool a cold head,
  • Can remain cold for months or even years in normal high and ultrahigh vacuum operation.
  • At some point, the pump is shut down, and allowed to heat up. The trapped gasses evaporate and are flushed out, a process known as regeneration.
  • Since cryopumps don’t use any oil in the vacuum side, they are used when very clean pumping is needed.

Sorption Pumps

Evacuate gas molecules from a volume by cryosorption, adsorbing them on a chilled Surface.

  • Sorption pumps are a type of cryopump that is often used as roughing pumps
  • They reduce pressures from the range of atmospheric to 10-3 Torr
  • As the sorbent saturates, the efficiency of a sorption pump decreases
  • They can be recharged by heating the zeolite material (preferably under conditions of low pressure) to a temperature near but below the breakdown point of the zeolite material’s porous structure.

Sputter Ion Pumps

Sputter ion pumps operate by ionizing gas within a magnetically confined cold cathode discharge.

The events that combine to enable pumping of gases under vacuum are:

  • Entrapment of electrons in orbit by a magnetic field.
  • lonization of gas by collision with electrons.
  • Sputtering of titanium by ion bombardment.
  • Titanium gettering of active gases.
  • Pumping of heavy noble gases by ion burial.
  • Diffusion of hydrogen and helium into titanium.
  • Dissociation of complex molecules into simple ones for pumping ease, e.g. CH4 breaks down into C and 2H2. Hydrogen is pumped separately. Carbon is no longer part of the residual gas and resides in solid form.

Vacuum Chambers

  • Glass and Metal Bell Jars
  • Spherical Chamber
  • Feed-through Collars
  • Standard Box Chamber

Operation of Piriani Gauge

Two filaments (platinum alloy in the best gauges). act as resistances in two arms of a Wheatstone bridge.

The reference filament is immersed in a fixed-gas pressure, while the measurement filament is exposed to the system gas.

Thermocouple Gauges

These gauges are used extensively in foreline monitoring to switch the main chamber from backing to high-vacuum pumps.

  • Operation: Measuring the voltage of a thermocouple spot-welded to a filament which is exposed to the system gas
  • The filament’s temperature depends on thermal losses to the gas
  • At higher pressure, more molecules hit the filament removing more heat energy and changing the thermocouple voltage
  • Working pressure range: between 10 and 10-3 Torr

Operation Principle of Hot Filament Ion Gauges

  • Heated filaments are biased to give thermionic electrons which is energetic enough to ionize any residual gas molecules during collisions.
  • The positive ions formed drift to an ion collector held at about 150V.
  • The current measures gas number density, a direct measure of pressure.
  • Measurement range is between 10-4 to 10-9 Torr.

Operation Principle of Penning Cold Cathode Gauges

  • Positive ions from a discharge bombard an active metal cathode (Zr, Th) to form secondary electrons.
  • These electrons have a high probability of colliding with and ionizing residual gas molecules.
  • The positive ions so formed complete the cycle by adding to the discharge.
  • Measurement range is between 10-2 and 10-5 Torr

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