TY - CPAPER
AU - Shin, Y.-M.
AU - Broemmelsiek, D.R.
AU - Crawford, D.J.
AU - Green, A.T.
AU - Lumpkin, A.H.
TI - Study on Beam Modulation Technique using a Masked Chicane at FAST (Fermilab Accelerator Science and Technology) Facility
J2 - Proc. of FEL2015
AB - Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling. The sub-ps beam modulation has been studied with a masked chicane by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the chicane design parameters (bending angle of 18 degree, bending radius of 0.95 m and R56 ~ - 0.19 m) and a nominal beam of 3-ps bunch length, the analytic model showed that a slit-mask with slit period 900 microns and aperture width 300 microns generates about 100 microns modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3- ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 microns of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (3.2 nC), by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments.
PB - JACoW
CY - Geneva, Switzerland
SP - 665
EP - 668
KW - simulation
KW - bunching
KW - dipole
KW - space-charge
KW - linac
DA - 2015/12
PY - 2015
SN - 978-3-95450-134-2
DO - 10.18429/JACoW-FEL2015-WEP045
UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/wep045.pdf
ER -