St and Ss for on ultrarelativistic bunches

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Philippe Piot
Posts: 83
Joined: 20 Aug 2008, 13:18
Location: Northern Illinois University & Argonne National Laboratory
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St and Ss for on ultrarelativistic bunches

Post by Philippe Piot » 22 Aug 2011, 08:19

Hi,
I am using elegant at low energy gamma~10 (for some tests ignoring space charge). I am attaching a typical output file (fin and out) I noticed that

sddsprintout -parameter=Ss -parameter=St -parameter=pAverage parmelabeamfwd.fin
Printout for SDDS file parmelabeamfwd.fin

Ss (m) = 2.163954e-09 St (s) = 1.025654e-15 pAverage (m$be$nc) = 1.222129e+01

Should not there be a beta factor only between Ss and St?

Thanks,

-- Philippe.
Attachments
parmelabeamfwd.fin
final parameter
(12.73 KiB) Downloaded 1701 times
parmelabeamfwd.out
output distribution
(14.55 KiB) Downloaded 1571 times

michael_borland
Posts: 1933
Joined: 19 May 2008, 09:33
Location: Argonne National Laboratory
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Re: St and Ss for on ultrarelativistic bunches

Post by michael_borland » 22 Aug 2011, 08:34

Philippe,

The relationship between St and Ss is not always simple. Ss is defined as the standard deviation of the distance traveled, whereas St is defined as the standard deviation of the arrival time. These are only related by the factor <beta>*c if the energy spread is sufficiently small.

--Michael

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