1. Klystron Modulator Systems for CLIC 500
NLC/JLC Revisited
Progress in technology for increased efficiency?
cost estimate

2. NLC Initial Baseline Design
75 MW Klystron (approx 2000 per LINAC)
Solenoid focussing (25kW per klystron)
55% efficiency
duty cycle (120 Hz, 1.6µs)
Average RF output power of klystron 14.4kW
1 kW heater power per klystron
Line type modulator
Pulse transformer 20% wasted power with rise and fall time
Thyratron switch, 600 W per thyratron
Overall Power Requirement per Klystron/Modulator
58 kW
116 MW/LINAC
This technology is known and works

3. Simplified RF System Layout
Klystron RF output
Compressed pulse
~ x2 to 3 in amplitude
Klystron
(~55% efficient)
TWT Klystron
Driver 2KW
LLRF
Pulse Compressor
Beam
Modulator
~80% efficient

4. NLC Baseline Design circa 2002
75 MW Klystron (approx 2000 per LINAC)
ppm periodic permanent magnet focussing (no solenoids)
55% efficiency
duty cycle (120 Hz, 1.6µs)
Average RF output power of klystron 14.4kW
1 kW heater power per klystron
Solid State Modulator (1 per two klystrons)
Pulse transformer 20% wasted power with rise and fall time
Overall Power Requirement per Klystron/Modulator(0.5)
31.5 kW
63 MW/LINAC
Klystron development was not finished, some problems with pulse width and high rep rate, peak power achieved
Modulators
Many iterations were done on different types of solid state switches, but still with pulse transformer. Only recently can we confidently say that this technology is properly developed

5. Realistic Goals for CLIC 500
PPM Klystron development will definitely need to continued(R&D Costs)
Pulse width
Duty cycle
New Marx Type modulators being developed at the moment that look promising
no pulse transformer hence faster rise and fall times greater efficiency >88%

6. Klystron Costing
Price enquiry out for industrialised X band klystron at the moment
Expected price ~ 500kCHF
Large orders for CLIC 500
Lots of dependencies
Manufacturer needs tests stands to condition tubes to full power, unless CLIC 500 pays for a large majority of these and eventually installs most of them in the LINAC then unit price wont come down significantly. Remember we need ~ 4500 klystrons that take probably 2 weeks per klystron to be conditioned
1 modulator can test ~20 klystrons per year

7. Modulator Costing
Approximate price for a modulator today is ~480 kCHF This can be significantly reduced for large quantities as long as there is a modular design I would estimate at least a 50% reduction

8. Additional costs Not to be forgotten
Pulse compressors, very difficult to manufacture and very expensive
Don't forget temperature stabilisation
TWT klystron drivers, very unreliable
~ 50 kCHF each,
a sold state solution should be found (does not exist at the moment)