General Information

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Beamline Parameters

  • Electron beam energy: 25 to 76 MeV
  • Temporal structure: Macropulse length: 3 microseconds
    Macropulse repetition rate from under 1 PPS to 3 PPS.
    Micropulse repetition period 12.25 ns or 24.5 ns.
    Micropulse length variable from about 1 ps FWHM to 10 ps FWHM.
  • Electron beam charge: continuously variable.
    Single micropulse charge from zero to a few nanoculombs.
    Bunch train charge up to about 10 nanoculombs. 
  •  Emittance: depends on various conditions, e.g. peak current, gun field, microbunch length etc. At 1 nC we have measured the emittance at 2.6 mm mrad (rms normalized) at a bunch length of 10 ps FWHM. The local emittance (Slice Emittance) is smaller, measured 1.4 mm mrad for a slice out of the 1 nC bunch.
  • Stability: (approx.) 1 ps in short term phase, 1% of beam diameter pointing, 1%-2% relative charge.

Some of the measured results below have been presented by D.T. Palmer, X.-J. Wang, R.H. Miller, I. Ben-Zvi, C. Pellegrini, J. Sheehan, J. Skaritka, H. Winick, M. Woodle and V. Yakimenko, Commissioning Results of the Next Generation Photoinjector, Proc. 7th Advanced Accelerator Concepts Workshop, Lake Tahoe, Oct. 13-18, 1996

Magnetic Element Parameters

  Aperture Max Current Volt. Drop Slope Eff. Length
BEPC quad 1X 40 mm 25 A 0.06 V/A 22.1 G/cm/A 10.4 cm
BEPC quad 2X 40 mm 25 A 0.1 V/A 22.1 G/cm/A 20.4 cm
SLAC 1X 28 mm 10 A 0.63 V/A 178.0 G/cm/A 10.16 cm
SLAC 1X 28 mm 10 A 1.1 V/A 181.5 G/cm/A 20.32 cm
6Q40 "Small" 40 mm 10 A 0.63 V/A 50 G/cm/A 7.6 cm

  Aperture Maximum Current Voltage Drop Slope (see calibration curves) Effective Length
Dipole 20 deg..   60 A 0.19 V/A 52.4 G/A 40.0 cm <
Spectrometer dipole 0-8 deg. 30 mm          24.0 cm
Solenoid 80 mm 200 A 0.1 V/A 14.0 G/A 19.5 cm
Steering coils:             
Inside solenoid IN/OUT 40 mm 1 A   49.97/40.83 G/A 10.2/10.5 cm
"Slim" trim 70 mm 4A   25 G/A 0.8 cm
"Old" trim    5A    7 G/A 17 cm