The OPAL Discussion Forum

[Andreas Adelmann <andreas.adelmann AT psi.ch>]

(AA: and here the original post of Chris)


In the process of comparing Bmad's time tracker with OPAL, I make a 2D field 
map based on pillbox fields (equations below). According to the OPAL manual, 
the basic columns are: E_z, E_\rho, dummy, B_t (which I assume is B_\phi). 
However, I seem to need to scale this last column by a factor of 10^6 to get 
the correct focusing. Is this documented?

Thanks!

- Chris -

Attachment: PastedGraphic-1.pdf
Description: Adobe PDF document

On Aug 22, 2011, at 7:26 AM, Andreas Adelmann wrote:

> Hi Andreas,
> 
> It really seems that the H_\phi ( = (1/\mu_0) B_\phi ) needs to be scaled 
> by exactly 10^6 in the field map file. Below is a test with Bmad (black) 
> and OPAL (red) through a 7-cell pillbox cavities. To check what Bmad is 
> doing, I also integrated the equations of motion in Mathematica, shown in 
> blue in the second plot.
> 
> In OPAL, how does the field map figure out the phase of the H-field? Do you 
> assume that it oscillates pi/2 out of phase with the E-field? Otherwise, 
> the field map file would need more information. 
> 
> To keep you up-to-date, I have field map data for our 'real' 7-cell cavity, 
> and will be doing comparisons with OPAL and Bmad soon.
> 
> Thanks,
> 
> Chris
> 
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