MAX IV R&D Accelerator division seminars
Vacuum systems and resources at MAX IV laboratory
18th September 2018, MAX IV, Lund
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 1 Marek Grabski Contents • What is vacuum - why do we need it in particle accelerators? • Basics of vacuum technology, • Gas sources, • Pumping technology, • Outlook of MAX IV storage ring vacuum systems, • Introduce vacuum team and services.
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 2 Marek Grabski What is vacuum? Vacuum is a space with no matter inside – practically not possible to achieve.
Vacuum in engineering and physics is a space in which the pressure is lower than atmospheric pressure and is measured by its absolute pressure.
Low pressure High pressure (high vacuum) (low vacuum)
Force [N] 2 Pressure is Area [m2] measured in Pascals, 1 [Pa] = 1 N/m
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 3 Marek Grabski What is vacuum?
The force exerted on the walls of an evacuated vessel surrounded by atmospheric pressure is: 1 kg/cm2 Atmospheric pressure
Vacuum
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 4 Marek Grabski Pressure units
Conversion table: units of pressure
In vacuum technology: mbar or Pa
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 5 Marek Grabski Vacuum ranges
1 Atm. = 1013 mbar =~ 1 bar
Pressure range [mbar] Low Vacuum 103 - 1 Medium Vacuum 1 - 10-3 High Vacuum (HV) 10-3 - 10-9 Ultra High Vacuum (UHV) 10-9 - 10-12 Extreme High Vacuum XHV < 10-12 rings, Storage Beamlines
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 6 Marek Grabski Why do we need vacuum in particle accelerator? Less beam-gas interaction: • Increase beam lifetime,
• Prevents to increase beam size,
• Reduces radiation hazard,
• Allows the light reach the sample,
• Helps to protect optics…
OLAV IV 2014, Matthew Cox Vacuum systems and resources at MAX IV laboratory, 18th September 2018 7 Marek Grabski Why do we need vacuum in particle accelerator?
The total beam lifetime in a particle accelerator is given by:
The interaction between beam particles and residual gas molecules consist of two main mechanisms: elastic and inelastic scattering which contribute to total beam lifetime.
Elastic, inelastic beam lifetime: 1 1 , ~ Z - atomic number of the residual gas (depends on gas specie),
ng - residual gas density (pressure).
Vacuum systems and resources at MAX IV laboratory, 18th September 2018 8 Marek Grabski Flow regimes - Mean free path [m] = - Diameter of flow channel [m] - Knudsen number [dimensionless] d FLOW REGIME
VISCOUS TRANSITIONAL MOLECULAR