Connectors, power pack, measurement systems

In all those measurement instruments which use the ionization of gas molecules as the measurement principle (cold-cathode and hot-cathode ionization vacuum gauges), strong magnetic leakage fields or electrical potentials can have a major influence on the pressure indication. At low pressures it is also possible for wall potentials which deviate from the cathode potential to influence the ion trap current. 

In vacuum measurement systems used in the high and ulfrahigh regimes it 

1) The torr is included in the table only to facilitate the transition from this familiar unit to the statutory units N m, mbar and bar. In future the pressure units tor, mm water column, mm mercury column (mm Hg), % vacuum, technical atmosphere (at), physicalatmosphene (atm), atmosphere absolute (ata), pressure above atmospheric and pressure below atmospheric may no longer be used. Reference is made to DIN 1314 in this context. 2) The unit Newton divided by square meters (N m ) is also designated as Pascal (Pa) 1 N m = 1 Pa. Newton divided by square meters or Pascal is the SI unit for the pressure of fluids. 3) 1 torr = 4/3 mbar fl torr = 1 mbar.  

Values of the product c of the mean free path X (and pressure p for various gases at 20 °C (see also Fig. 9.1) 

Avogadro constant Na 6.0225-lO SmoM Number of particles per mol, formerly Loschmidt number 

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