10.15 CORGPIPE—A corrugated round pipe, commonly used as a dechirper in linacs.

A corrugated round pipe, commonly used as a dechirper in linacs.
Parallel capable? : yes
GPU capable? : no
Back-tracking capable? : no






Parameter Name UnitsType Default

Description






L M double0.0

length






RADIUS M double0.0

pipe radius






PERIOD M double0.0

period of corrugations (<< radius recommended)






GAP M double0.0

gap in corrugations (< period required)






DEPTH M double0.0

depth of corrugations (<< radius, >  period recommended)






DT S double0.0

maximum time duration of wake (0 for autoscale)






TMAX S double0.0

maximum time duration of wake (0 for autoscale)






N_BINS long 0

number of bins for charge histogram (0 for autoscale)






INTERPOLATE long 0

interpolate wake?






SMOOTHING long 0

Use Savitzky-Golay filter to smooth current histogram?






SG_HALFWIDTH long 4

Savitzky-Golay filter half-width for smoothing






SG_ORDER long 1

Savitzky-Golay filter order for smoothing






CHANGE_P0 long 0

change central momentum?






ALLOW_LONG_BEAM long 0

allow beam longer than wake data?






RAMP_PASSES long 0

Number of passes over which to linearly ramp up the wake to full strength.






GROUP string NULL

Optionally used to assign an element to a group, with a user-defined name. Group names will appear in the parameter output file in the column ElementGroup






This element implements the longitudinal wake for a corrugated pipe using a model by K. Bane [38]. The method used is identical to that for the WAKE element. The only difference is that instead of providing a file to specify the wake, one specifies the parameters of Bane’s model, as described above.

Setting the N_BINS and TMAX paramaters to 0 is recommended. This results in auto-scaling of the number of bins and the time spacing of the wake to ensure sufficient length to cover the beam and a sufficiently fine time step to resolve the oscillations in the wake.

As with WAKE, the default degree of smoothing (SG_HALFWIDTH=4) may be excessive. It is suggested that users vary this parameter to verify that results are reliable if smoothing is employed (SMOOTHING=1).

CSBEND