1. 1 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 The Evolution of Vacuum System Design for Accelerators over 30 years at Daresbury Lab Ron Reid Group Leader, Vacuum Science Group ASTeC CCLRC Daresbury Laboratory Warrington WA4 4AD, UK

2. 2 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Outline Our second accelerator (SRS) System Design Pressure calculations Materials Pumps Gauges Conditioning Our next accelerator

3. 3 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 The SRS NINA SRS (1980) First 2 nd Generation Light Source Medium Energy 2GeV, 1A (350mA), 100m, 3.88Å 10 -9 Torr; 12 hours 40 hrs @300mA Two major upgrades

4. 4 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 The SRS

5. 5 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 The SRS

6. 6 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Simple Vacuum Layout

7. 7 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Vacuum System Design - Then Highly simplified – Analytical solution of gas flow equations No PCs – mainframes with turnround of days Simple “finite element” models Fortran decks

8. 8 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Vacuum System Design - Now PCs ubiquitous Realistic calculations of complex systems Monte Carlo simulations Angular coefficients Quick optimisations of layouts

9. 9 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Materials Stainless steels as now Aluminium less common Absorbers Copper Finite element calculations Glidcop Fabrication Techniques EB and plasma welding now more generally available

10. 10 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow Roughing

11. 11 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm

12. 12 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps

13. 13 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps Turbos

14. 14 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing

15. 15 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil lubricated; Air Bearing Greased ceramic Magnetic

16. 16 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil lubricated; Air Bearing Greased ceramic Magnetic Ion Pumps

17. 17 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing Greased ceramic Magnetic Ion PumpsDiode; Triode; “Noble”

18. 18 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing Greased ceramic Magnetic Ion PumpsDiode; Triode; “Noble” Diode; Triode; DI; Starcell

19. 19 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing Greased ceramic Magnetic Ion PumpsDiode; Triode; Noble Diode; Triode; Noble; Starcell UHV

20. 20 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing Greased ceramic Magnetic Ion PumpsDiode; Triode; Noble Diode; Triode; Noble; Starcell UHVTSP

21. 21 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumps ThenNow RoughingSorption; Diaphragm Dry mechanical pumps TurbosOil sealed Air Bearing Greased ceramic Magnetic Ion PumpsDiode; Triode; Noble Diode; Triode; Noble; Starcell UHVTSPTSP; Neg

22. 22 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumping schemes In SRS about 50% of circumference is dipole magnets vacuum vessels Main radiation absorbers are linear (distibuted) in dipole vessels Main gas load Most restricted pumping Solution: DIPs

23. 23 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 DIPs

24. 24 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumping schemes In SRS the DIPs give almost half the applied pumping speed during beaming Losing just one DIP gives a noticeable decrease in lifetime

25. 25 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Pumping schemes Our new machine designs have much smaller apertures, dipoles occupy only a small fraction of the circumference DIPs no longer appropriate Machines use discrete photon stops Current preferred solution NEG (discrete and film)

26. 26 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Gauges Little change in type of gauge Except BAG often replaced by IMG Main difference is the electronics – now compact, more reliable Biggest difference is in control - then home brewed, now uses standard interfaces

27. 27 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Conditioning Then - beam scrubbing effect was known But limited data and best measured values of η were ~10 -6 mol γ -1 SRS design needed 10 -7 Cleanup rate not well characterised Now much greater range of systematic data and clean up rates predictable as a function of beam dose

28. 28 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Our next accelerator – 4GLS

29. 29 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 4GLS Direct vacuum challenges are few Most of the machine needs to be at modest UHV, maybe HV But Photocathode gun is XHV Superconducting linacs Particulate Cleanliness is a real challenge

30. 30 of 30 rjrALBA Workshop, Barcelona, 12-13 th Sept 2005 Concluding Ramblings Thanks for your indulgence!