1. Klystron efficiency

2. Current status
We are operating four X-band test stands at CERN. All operate with solid state modulators.
Two are using 50 MW klystrons. Original tube and design by SLAC, so-called XL-5. Current tubes and spare built by CPI.
Collaborators are running a further 4+ tubes of this type, use expanding.
We now study the implementation into a klystron-based version of CLIC.

3. Observations on power consumption
Electronic efficiency – Current tube only about 45%. We have launched with SLAC a design study tube which incorporates the latest ideas about high efficiency. Should result in higher efficiency tube, >65% or so and lower modulator voltage, below 400 kV (from 430 kV).
Solenoid – Current normal conducting solenoid consumes 20 kW, same average power as klystron itself. Going to superconducting solenoid has the potential to reduce this consumption by an order of magnitude. Low field application so conductor of choice is MgB2. We look towards order demonstrator unit. PPM (Periodic Permanent Magnet) also potential solution but not clear if this is compatible with high-efficiency

4. New ideas on klystron efficiency
Commercial Prototype of High Efficiency S-band Pulsed BAC MBK
Igor Guzilov1, Roman Egorov1, Gerard Mcmonagle2, Igor Syratchev2, Ben Woolley2
1JSC “Vacuum device’s basic technologies”, Moscow, , Vvedenskogo str.,3,k.1
RUSSIAN FEDERATION,
2CERN, CH-1211, Geneva 23, Switzerland
“To minimise the development risks and fabrication cost of the first BAC MBK prototype, we have decided to facilitate a retrofit design of an existing klystron; MBK KIU-147. It has been in production in Russia (FSUE “Toriy”) for almost 15 years and operates at 60 kV, 290 A with 42% RF power production efficiency.”
Figure 5: The efficiency (triangular) and RF power production (circle) in saturation at 3.003 GHz as functions of high voltage.

5. I. Syratchev High efficiency klystrons.
New bunching technologies on one slide.
Core Oscillations Method (5.75 m)
Bunching Alignment Collecting, 2.44 m
133.8 kV, A, 1.4 MW at 0.8 GHz, 80(+)%
COM
Core Stabilization Method
BAC
High Efficiency International klystron Activity. Since 2013.
CSM_2L3B3, 1.88 m
CSM
CSM_23B1, 1.72 m
I. Syratchev

6. High efficiency klystron for FCC
High efficiency klystron for FCC. PIC simulations with CST(3D) and MAGIC (2D)
Efficiency 80.7%
MAGIC
HE compact (1.7 m) L-band, 1.4 MW, CW klystron for FCC has been design within HEIKA using CSM bunching technology.
Efficiency 80.3%
I. Syratchev

7. The choice of bunching technology may drive the applicable frequency range and multi-beam options (cost/performance):
L-band
S-band
C-band
X-band
Kladistron
CSM/modest MBK
Medical/industrial
CLIC klystron based
X-band FEL
LHC,FSS,ESS,ILC
BAC/MBK
1/6 MW
5-10 MW, <60kV
COM/single beam
CLIC, TBA
High perveance MBK HE tubes (!?)
50+ MW
10-20 MW
I. Syratchev

8. High efficiency X-band klystron
Full presentation this afternoon!

9. High efficiency X-band klystron
Full presentation this afternoon!

10. Superconducting klystron solenoid
Full presentation this afternoon!

11. Superconducting klystron solenoid
Full presentation this afternoon!