1. Anders Sunesson RF Group ESS Accelerator Division 2013-01-30
ESS warm linac RF
Anders Sunesson
RF Group
ESS Accelerator Division

2. Overview Warm linac RF Discussion (CAD model) Low level RF RF Sources
RF distribution
Discussion

3. Schedule Installation starts July 2017 (access gallery)
Warm linac commissioning Q3 2018
80 MeV Q1-Q2 2019
Beam generating protons (>400 MeV)expected October 2019 – this means warm linac, spoke and medium beta sections needed
THIS IS €%#&/’* TIGHT

4. Layout and placement Gallery
Waveguides

5. LLRF, master osc Sets amplitude and phase of RF power to cavity
Master RF clock + distribution to all cavities
Monitors RF signals in RF cell
Monitors and controls cavity tuning
Monitors waveguides, loads, circulators, modulators, klystrons (RF signals, temperature, pressure,…)
Talks to ICS

6. RF system basic layout
NC or SC cavity

7. LLRF

8. To discuss LLRF Tuning systems warm linac? (Touched yesterday)
Does LLRF control tuning for warm linac?
Interface w LLRF systems?

9. RF sources One per cavity or tank– RFQ, Buncher, DTL Operation data:
14 Hz pulse frequency
MHz
Pulse width required up to 3.5 ms (include filling times of cavities)

10. Amplifier powers Baseline according to power levels below Cavity
Pulse power (kW)
RF Frequency (MHz)
Number
Sat Power (kW)
Choice
RFQ
1300
352.21 1
1700
Klystron
Bunchers 15 3 20 SS
DTL
2200 (??) 4
2900
Spoke 28
310
Tetrode
Medium β
704.42 60
670
High β
120
1150
Klystron/IOT

11. Klystron A klystron is big and heavy, at 352 5x2x1 m3, ca 4000 kg
Gain dB, efficiency 60-70%
A klystron requires pulsed HV ( kV, A)
Klystrons can be designed for several MW peak
A klystron requires cooling water

12. Klystron Example of klystron maybe suitable for RFQ and DTLs
2 suppliers

13. To discuss RF sources Verify power levels RFQ, bunchers, DTL
For DTL, the 2.9 MW means that the RF max in the tank will be 2.75 MW (max 5% loss)– is this ok???

14. RF Distribution and cavities
RF from source to cavity input couplers
For bunchers, coax transmission line, 7/8 inch
For RFQ, DTLs full and half-height WR-2300
Circulator, loads to protect from reflected energy
Monitoring: matching, arcs, temp….
Complication: 2 ports per DTL tank, 2(?) Ports for RFQ

15. Linac4 set-up

16. ESS splitter set-up
Magic tee? 3 dB hybrid?

17. To discuss distribution
Phase difference requirements between coupler RFQ and DTL?
Phase shifter needed to compensate?
Number and type of ports RFQ? Structures – iris/loop?
Vacuum transition point coupler?
Cooling couplers?
Cabling needed?

18. To discuss layout
Width or envelope fully equipped– fits in current design?
Nominal peak powers
Construction drawings or a max outline– these are needed to start detailed gallery/tunnel design!
Cooling systems
Waveguide routing/cable routing

19. Thank You
Anders Sunesson
ESS