longitudinal emittance

[jtobin]

Hello all,
I want to plot z-emittance as a function of s along the linac using sddsprocess. I have the output stored in *.s file.
I get confused between Ss and St. So, how do i plot the normalized longitudinal emittance along the linac? Thanks..
regards,
Charles

[michael_borland]

Charles,

A discussion of Ss vs St is available in the manual at
http://www.aps.anl.gov/Accelerator_Syst ... ode14.html

The "sigma" output file from &run_setup include several quantities that can be used to compute the longitudinal emittance:

sddsprocess run.sig -define=col,el,"St Sdelta * sqr s67 sqr - sqrt",units=s

In algebraic notation, that's el = sqrt((St*Sdelta)^2 - s67^2), where s67 = <(t-<t>)*delta>.

--Michael

[jtobin]

Thank you Michael for your reply - quick as usual (definitely a feature of elegant!).

regards,
Charles