ESS warm linac RF

Anders SunessonRF Group

ESS Accelerator Division

2013-01-30

Overview• Warm linac RF

– (CAD model)– Low level RF– RF Sources– RF distribution

• Discussion

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

Layout and placement GalleryWaveguides

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

RF system basic layout

NC or SC cavity

LLRF

To discuss LLRF

• Tuning systems warm linac? (Touched yesterday)

• Does LLRF control tuning for warm linac? • Interface w LLRF systems?

RF sources

• One per cavity or tank– RFQ, Buncher, DTL• Operation data:

– 14 Hz pulse frequency– 352.21 MHz– Pulse width required up to 3.5 ms (include filling

times of cavities)

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 15 352.21 3 20 SS

DTL 2200 (??) 352.21 4 2900 Klystron

Spoke 165-239 352.21 28 310 Tetrode

Medium β 122-514 704.42 60 670 Klystron

High β 394-872 704.42 120 1150 Klystron/IOT

Klystron• A klystron is big and heavy, at

352 5x2x1 m3, ca 4000 kg• Gain 40-50 dB, efficiency 60-

70%• A klystron requires pulsed HV

(90-110 kV, 10-20 A)• Klystrons can be designed for

several MW peak• A klystron requires cooling

water

Klystron

• Example of klystron maybe suitable for RFQ and DTLs

• 2 suppliers

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???

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

Linac4 set-up

ESS splitter set-up

• Magic tee? 3 dB hybrid?

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?

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

Thank You

Anders SunessonESS