# Formulas

## 1 Introduction to Vacuum Technology

- Formula 1-1
- Barometric formula
- Formula 1-2
- Numerical barometric formula
- Formula 1-3
- Definition of pressure
- Formula 1-4
- Boyle-Mariotte law
- Formula 1-5
- Gay-Lussac’s law
- Formula 1-6
- General equation of state for ideal gases
- Formula 1-7
- Equation of state for ideal gases I
- Formula 1-8
- Equation of state for ideal gases II
- Formula 1-9
- Most probable speed
- Formula 1-10
- Most probable speed
- Formula 1-11
- Mean free path
- Formula 1-12
- Mean free path II
- Formula 1-13
- Knudsen number
- Formula 1-14
- Reynolds number
- Formula 1-15
- pV throughput
- Formula 1-16
- Throughput of a vacuum pump
- Formula 1-17
- Volume flow rate, or pumping speed, of a vacuum pumpe
- Formula 1-18
- Definition of conductance
- Formula 1-19
- Ohm’s law
- Formula 1-20
- Parallel connection conductance
- Formula 1-21
- Series connection conductivities
- Formula 1-22
- Blocking of an orifice
- Formula 1-23
- Orifice flow
- Formula 1-24
- Orifice conductivity
- Formula 1-25
- Orifice conductivity for air
- Formula 1-26
- Conductance of a pipe in laminar flow
- Formula 1-27
- Conductance of a pipe in laminar flow for air
- Formula 1-28
- Molecular pipe flow
- Formula 1-29
- Passage probability for long round pipes
- Formula 1-30
- Molecular pipe conductivity
- Formula 1-31
- Molecular pipe conductivity
- Formula 1-32
- Desorption rate
- Formula 1-33
- Desorption rate from plastics
- Formula 1-34
- Permeation
- Formula 1-35
- Leak rate
- Formula 1-36
- Ultimate pressure as a function of time

## 2 Basic calculations

- Formula 2-1
- Roots pump gas load
- Formula 2-2
- Compression ratio of Roots pump
- Formula 2-3
- Compression ratio of Roots pump for laminar flow
- Formula 2-4
- Compression ratio of Roots pump for molecular flow
- Formula 2-5
- Pumping speed of Roots pumping station with overflow valve open and at high fore-vacuum pressure
- Formula 2-6
- Pumping speed of Roots pumping station with overflow valve closed and fore-vacuum pressure close to differential pressure
- Formula 2-7
- Pumping speed of Roots pumping station at high intake pressure
- Formula 2-8
- Pumping speed of Roots pumping station at low intake pressure
- Formula 2-9
- Pump-down time
- Formula 2-10
- Calculating the pumping speed
- Formula 2-11
- Gas throughput for pumping down vapors
- Formula 2-12
- Calculation of the condensation surface area
- Formula 2-13
- Base pressure of a vacuum system
- Formula 2-14
- Diffusion coefficient (T)

## 4 Vacuum generation

- Formula 4-1
- Compression ratio
- Formula 4-2
- Pump combination gas flow
- Formula 4-3
- Backflow conductance
- Formula 4-4
- Actual compression ratio
- Formula 4-5
- Pumping speed recursion formula
- Formula 4-6
- Water vapor tolerance
- Formula 4-7
- Water vapor capacity
- Formula 4-8
- Turbopump compression ratio
- Formula 4-9
- Turbopump pumping speed
- Formula 4-10
- Turbopump pumping speed
- Formula 4-11
- Specific pumping speed
- Formula 4-12
- Holweck stage pumping speed
- Formula 4-13
- Holweck stage compression ratio
- Formula 4-14
- Ultimate pressure

## 6 Mass spectrometers and residual gas analysis

- Formula 6-1
- Kinetic energy
- Formula 6-2
- Lorentz force
- Formula 6-3
- Equilibrium of forces
- Formula 6-4
- Path radius
- Formula 6-5
- Quadrupole deflection voltage
- Formula 6-6
- Stability parameter
*a* - Formula 6-7
- Stability parameter
*q* - Formula 6-8
- Stability condition U
- Formula 6-9
- Stability condition V
- Formula 6-10
- High-pass condition
- Formula 6-11
- RF power
- Formula 6-12
- Scatter
- Formula 6-13
- Ion current

## 8 Contamination management solutions

- Formula 8-1
- Surface coverage
- Formula 8-2
- Dose of contamination