1. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 The MAX IV 3 GeV Ring Vacuum System A Beam Dynamics Perspective Pedro F. Tavares MAX IV Laboratory

2. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Summary ● The MAX IV Design Concept ● MAX IV Parameters ● Trends in SR Vacuum Systems ● MAX IV vacuum design challenges – Heat load – Vacuum Pressure – Impedance ● Recent results from MAX IV ● Pushing the envelope – beyond MAX IV

3. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 MAX IV - An integrated Solution MBA Lattice Ultra-low emittance robust, high stability. large momentum aperture Large Number of Magnets Small Magnet Apertures Wake- Fields Low RF frequency Full Energy Injector LINAC: Short Pulses Long Bunches Landau Cavities Compact Magnet Design. High precision, lHigh vibration frequencies Narrow vacuum Chambers Multi- purpose Strong Magnets IBS Low Vacuum Conductance High Heat Load Density Copper Chambers 100 % NEG Coating

4. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Annika Nyberg, MAX IV-laboratoriet, 2012 MAX IV – an overview Linear Accelerator 3 GeV Storage Ring 1.5 GeV SR Short Pulse Facility

5. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 © Photo: Perry Nordeng 18-Sept-2014

6. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 The trend towards smaller apertures R.Nagaoka & K.Bane, J. Synchrotron Rad. (2014). 21, 937–960

7. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 The trend towards smaller apertures - Long Straights T.Tanaka et al, 27 th FEL conference, 2005. 3D model for impedance calc. of MAX IV IVU – 4 mm gap Picture by D.Olsson

8. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 The trend towards smaller apertures - Long Straights ● Multipole Kicker for Transparent Top-up ● Based on BESSY design ● Vertical aperture = 8 mm. Pictures by P.Lebasque SOLEIL

9. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 The Challenges of small apertures Vacuum Pressure – Lifetime reduction Iimit maximum current/energy chamber (BPM) motion may affect stability Limitation to maximum current Chamber heating by induced fields

10. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Scaling of Impedance of common components (low freq.) Resistive wall: Elliptical iris with semi-axes h, a Pipe transition, transition height h Small semispherical object radius a From K.Y.Ng in Handbook of Acc. Physics by A.Chao

11. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 MAX IV 3 GeV Ring Vacuum System Distributed cooling Ribs Cooling for corrector area Welded bellows Chamber body Ribs Beam direction Picture Eshraq Al-dmour NEG coating : distributed pumping Copper chamber: high thermal conductivity allows distributed cooling high electrical conductivity reduces impedance Design by ALBA

12. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Dealing with Collective Instabilities ● Passively operated 3 rd Harmonic Cavities lengthen the bunches reducing the overlap of the bunch spectrum with the impedance Pedro F. Tavares et at, J. Synchrotron Rad. (2014). 21, 862–877

13. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 First Assembly Results from MAX IV – Mockup tests Pictures by Chiara Pasquino

14. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Beyond MAX IV – exploring future possibilities ● Can the MBA concept be used to design a storage ring that provides a bare lattice natural emittance ̴ 10 pm rad within the MAX IV 3 GeV ring circumference (528 m) ? ● If we take the present trend to smaller gaps to a new level, and consider that “…when it is necessary that a magnetically significant dimension of a magnet is very small, a permanent magnet will always produce higher fields than an electromagnet”, K. Halbach J.App.Phys (1985), Vol. 57, N. 1. ● Large scale use of permanent magnet technology could play a key role in this development.

15. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014

16. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Current SR Projects using PM Technology (for dipole magnets) ● Sirius ● ESRF-II ● Spring 8-II

17. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Beyond MAX IV – an exercise BH SD SF QF BH 19-BA lattice in the MAX IV 3 GeV ring tunnel Lattice design: OPA (A.Streun) Elegant (M.Borland)

18. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Beyond MAX IV – an exercise 19-BA lattice in the MAX IV 3 GeV ring tunnel

19. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 19-BA lattice in the MAX IV 3 GeV ring tunnel - Dynamic and momentum aperture No errors !

20. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 19-BA lattice in the MAX IV 3 GeV ring tunnel – Magnet Parameters Magnet bore radius = 5.5 mm

21. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Challenges ● Magnet Design (field quality, rad. damage, temp. dependence, trim) ● Light Extraction ● On-axis injection (fast kickers), Swap-out as proposed by M.Borland? ● Collective effects (incoherent (IBS) and coherent) – More lengthening ? ● Heat load on chambers ● NEG coating of very small aperture chambers ● Mechanical integration ●.......

22. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 High Gradient PM Quadrupole Examples 7 mm bore radius, 285 T/m – Mihara et al, EPAC2004, Iwashita et al, PAC2003

23. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Conclusions ● As a result of the introduction of the MBA lattice concept, small aperture magnets and vacuum systems are becoming a common choice for storage-ring based light sources. ● This naturally leads to reconsider proposals for using permanent magnets in storage ring lattices, which have been around for a long time and in many labs. ● A few synchrotron radiation facilities (LNLS, ESRF, Spring 8) labs have recently started going seriously in that direction. ● The time may have come when the benefits of large scale use of permanent magnets in storage ring lattices outweigh the risks/costs ? This could lead to yet another order of magnitude jump in source brightness

24. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 One achromat MAX IV 3 GeV ring vacuum system layout BPM Ion pump location Absorber location Beam direction Sector valve location VC10 VC1 VC2 VC3 VC4 VC5 VC6 VC7 VC8 VC9 Slide by E.Al-dmour

25. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Impedance optimization of vacuum components ● Flanges: MA IV solution and Sirius solution MAX IV Spigot Flange Sirius Flange (from R.Nagaoka, J. Synchrotron Rad. (2014). 21, 937–960

26. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 BPM Thermal Motion BPM Bodies fixed to the Blocks. Geometry is as symmetrical as possible – if heat load changes, dimensions change but center (nearly) does not move. Pictures by J.Alhbäck

27. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Max = 3.71 µm Vertical deformation Min =-2.13 µm ± 0.4 µm shift for 0 to 500 mA Calc. by ALBA

28. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Dealing with Collective Instabilities ● Reserve in HC shunt impedance allows operation over a large current range and/or detuned operation to avoid Robinson Instability driven by the HC fundamental mode Pedro F. Tavares et al, PRST-AB (2014) 17, 064401

29. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 In order to estimate the effective pumping speed after activation, it is possible to inject a small flow of H 2 gas into the system (i.e. heating the bellow of the pumping group at different temperatures). The difference in pressure during injection with the SIP on and off will give an evaluation of the effective pumping speed of the NEG. It is possible to translate that into a sticking probability thanks to a molflow simulation. ∆P H2 First Assembly Results from MAX IV

30. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 NL Dynamics – Chromaticity Correction

31. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 Touschek Lifetime

32. MAX IV 3 GeV Ring Vac. System – A beam dynamics perspective December 2014 MAX IV - An integrated Solution MBA Lattice Ultra-low emitance robust, high stability. large momentum Aperture Large Number of Magnets Small Magnet Apertures Wake- Fields Low RF frequency Full Energy Injector LINAC: Short Pulses Long Bunches Landau Cavities Compact Magnet Design. High precision, High vibration frequencies Narrow vacuum Chambers Multi- purpose Strong Magnets IBS Low Vacuum Conductance High Heat Load Density Copper Chambers 100 % NEG Coating