RF Cavity Parameters

Channel Length 2.5 m.
Beam Aperture (Diameter) 64 cm.
Pi phase advance per cell

The data in this table may be revised occasionally. Please check back often.


Parameter Value
Beta 0.87 (pz=187 MeV/c)
Energy Loss Factor in Hydrogen 0.303 MeV/cm
Frequency 201.25 MHz
Accelerating Phase Angle sin(25 o)
Hydrogen Absorber Length 30 cm
Average Accelerating Gradient 11.3 MV/m
Peak Accelerating Field 16.4 MV/m
Peak Surface Field 28.0 MV/m
Kilpatrick Limit 14.8 MV/m
Cavity Type Open cell with crossed tubes over aperture
Number of Cells per Cavity 3
Cavity Dimensions The internal radius is 0.600m, determined by MAFIA calculations. The internal cell length, lambda*beta/2, is 0.648m. The length of an accelerating section is 1.944m. Three coaxial lines feed the cavities from room temperature (warm bore) ports, 0.17m diameter, passing through the magnet cryostat.
Impedance 35 Mohm/m (no transit time correction, Z=V2/(P*d))
Shunt Impedance ZT2=16.68 Mohm/m, 10.81 Mohm per cell
Transit Time Factor T 0.69
Peak Voltage per Cell 10.6 MV
Voltage per cell 7.3 MV
Qo 69,000
Fill Time 52 microseconds, critically coupled (one fill time)
Bunch Length (sigma) 10 cm
Number of Bunches in Train 30
Bunch Train Length 150 ns
RF pulse 156 microseconds
Duty Cycle 2.34x10-3
Peak Power Requirement (16.4x106)2/35x106 = 7.68 MW/m
Peak Power per Cell (7.68/3)x1.944 = 5.0 MW
Average Power per Cell 5.0 MW x 2.34x10-3 = 11.6 kW
Window Type 4 cm diameter Al crossed tubes
Average Power On Tubes 130 W (worst tube)
Conductivity Al/Cu 3.72x107 / 5.8x107 S/m
Skin Depth 4.6 microns (Cu), 5.8 microns (Al)

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  • Thomas G. Jurgens <jurgenst@fnal.gov>
  • Last Updated: 9 December 1999