Don't see expected IBS effect
Posted: 26 Oct 2021, 14:25
Hello,
I am having an issue with IBSCATTER element in my beam line:
that it does introduce any additional energy spread. Based on SLAC-TN-05-026 report by Z. Huang, the energy spread by the end of 9 meter section should be 3 keV for 100pC bunch with 54.487 nm normalized emittance, 478 um rms bunch length and 191um rms transverse size (see attached).
Here is my control file:
Can anybody tell me why theory prediction does not match the calculations?
Thank you.
Petr
I am having an issue with IBSCATTER element in my beam line:
Code: Select all
q: charge, total=1e-10
samp: sample, fraction=1
cav2_c: rfcw, L=0.0526, CELL_LENGTH=0.0263, &
N_KICKS=2, CHANGE_P0=1, &
...
cav_c: rfcw, L=0.4997, CELL_LENGTH=0.0263, &
N_KICKS=19, CHANGE_P0=1, &
...
cav_h: rfcw, L=0.4471, CELL_LENGTH=0.008766666666666667, &
N_KICKS=44, CHANGE_P0=1, &
...
ibs: ibscatter, nslice=1024, isring=0, bunched_beam_mode=0
sr: mark
lin2_c: line = (cav2_c, sr, ibs)
lin_c: line = (19*lin2_c)
lin_h: line = (cav_h, sr, ibs)
linac: line = (q, samp, 6*lin_c, 6*lin_h)
Here is my control file:
Code: Select all
&global_settings
mpi_io_write_buffer_size = 100000 ! advice from Borland 100K
&end
&run_setup
lattice = linac.lte,
use_beamline = linac,
expand_for = ibsTopGun_3p7M.sdds,
always_change_p0 = 1,
output = %s.out,
final = %s.fin,
sigma=%s.sig
&end
&twiss_output
filename = %s.twi,
matched = 0,
beta_x=201.6875
alpha_x=-14.78305
eta_x=6.698627e-5
etap_x=3.079309e-6
beta_y=201.7416
alpha_y=-14.78672
eta_y=-1.900780e-4
etap_y=-8.769033e-6
&end
&run_control
n_steps = 1
&end
&sdds_beam
input = ibsTopGun_3p7M.sdds,
input_type = "elegant",
sample_fraction = 1,
!reuse_bunch = 1
&end
&track &end
Thank you.
Petr