Vacuum Technology Introduction Pumps Valves Gauges Seals Vacuum

Vacuum Technology Introduction • Pumps • Valves • Gauges • Seals Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

UHV Pumps • Capture pumps are the dominating pumps for vacuum systems for synchrotron light sources • Titanium is the most common getter • sputter-ion pumps use chemical and ionization pumping effects Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Sputter Ion Pumps Standard Diode Highest pumping speed per unit volume. Low pumping speed for noble gases (<5% for Ar). Noble Diode A part of the cathode material is replaced with Tantalum to achieve a higher pumping speed for noble gases. Noble gas ions are neutralized and “bounced back” on the cathode and buried in other parts of the pump. Energetic neutrals have far greater penetrating depth. Star. Cell Cathode plates are replaced with grids of Ti-strips Number of neutrals due to glancing incidence is increased. Pumping speed for noble gases of 20 -25%. Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Sputter Ion Pumps • At SLS storage ring we use standard diode pumps with Varian Dual controllers • Typically 8 pumps share the same pump controller • All pump controllers run in STEP VOLTAGE mode P > 10 -7 mbar 7000 V 10 -8 < P < 10 -7 mbar 5000 V P < 10 -8 mbar 3000 V Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

NEG Pumps NEG Strips Courtesy of E. Trakhtenberg electron channel • APS 5 mm Undulator chamber • ST 707 NEG strips • 350 -450°C activation temperature • High pumping speed and pumping NEG Strips capacity for noble gases NEG Cartridges • Getter material Zr-V-Fe and Ti – V • Very compact with high pumping speed and capacity Courtesy SAES Getters • Flange size DN 40, 100, 150 CF Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Titanium Sublimation Pumps • Ti-filament periodically heated with high currents. • Ti evaporates and generates a getter film on the chamber wall or cooled screen. • Progressive saturation and reduction of pumping speed with time. Ti-Filament Chamber wall Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Valves • All metal valves are used for vacuum systems of synchrotron light sources • RF shielded sector gate valves • All metal angle valves for the connection of roughing pumps • All metal gate valves for beamline frontends Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Valves SLS Sector Vacuum Scheme Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

Vacuum Gauges • Total pressure gauges for synchrotron light sources • Total pressure measurement • Sensor for vacuum interlock • Cold cathode gauges (IMG) are mainly used for total pressure measurement • At SLS we use active gauges with on board electronics • Pirani gauges • RGA Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz

UHV flanges All Metal Flanges Connections CF-Flange with RF-Bridge (BESSY II) CF-Flange with Small gap (ESRF, ANKA) Flat Seal-Flange (ASP, CLS, SLS) Temperature control is required Vacuum Workshop on Vacuum Systems for Synchrotron Light Sources, Barcelona, Vacuum Technology, 12 th and 13 th September 2005 L. Schulz