Linac RF Source

1
Linac RF Source

• Recommendations for Items 22,23,24,46,47

Chris Adolphsen
2
Modulators (115 kV, 135 A, 1.5 ms, 5 Hz)

• Baseline Choice DESY/FNAL Pulse Transformer
• Pros Seven units built by industry - no major
  reliability problems. Choice for the XFEL DESY
  continuing to work with industry on improvements.
  FNAL working on a more cost efficient and compact
  design.
• Cons Susceptible to single-point failures,
  large oil-filled transformer (in tunnel for
  single tunnel design), high labor cost to
  assemble.
• Alternate Choice Marx Generator
• Pros Solid state, 1/n redundant modular design
  for inherent high availability and reliability.
  No transformer, air cooled. Highly repetitive
  IGBT modules, cheap to manufacture may be up to
  50 less expensive.
• Cons No working model - first prototype in
  2006. Need to develop long-haul 115 kV
  transmission line if have clustered rf sources.

3
Klystrons

• Baseline Choice 10 MW Multi-Beam Klystrons Only
  high power, high efficiency tube available (two
  Thales tubes have achieved full spec after gun
  fix, only few hundred hours operation at 10 MW).

4
Alternatives to be Considered(Long development
time, no funding in 2006)
5 MW Inductive Output Tube (IOT)
10 MW Sheet Beam Klystron (SBK)
Low Voltage 10 MW MBK
Parameters similar to 10 MW MBK
Voltage e.g. 65 kV Current 238A More
beams Perhaps use a Direct Switch Modulator
Klystron
Output
IOT
Drive
SLAC
CPI
KEK
5
RF Components per Linac

• Average cryomodule gradient 31.5 MV/m
• Overhead for BNS and failed units 5
• Number of cavities (ignoring BC, Undulator)
• 1.05(250-5)/(0.03151.038) 7868
• Number of 8-cavity cryomodules 984
• Number of 10 MW rf stations 328
• Beam Power / RF Power Capability
• 245 GeV 9.5 mA / (328 10 MW) 71

6
RF Distribution Math(for 35 MV/m Max Operation)
10 MW Klystron

• 35 MV/m 9.5 mA 1.038 m 345 kW (Cavity
  Input Power)
• 24 Cavities
• 1/.93 (Distribution Losses)
• 1/.89 (Tuning Overhead)
• 10.0 MW