The OPAL Discussion Forum

["Zhang Hui (PSI)" <hui.zhang AT psi.ch>]

Hello Andreas,

In our experience with the simulation of the COMET cyclotron, the probe saves 
data, but not always the complete data. For instance, it sometimes fails to 
register most or all particles of a turn.

Best regards, Hui
 

__________________________________________
Paul Scherrer Institut 
Dr. Hui Zhang
WBGA/C34
CH-5232 Villigen PSI

Telefon: +41 56 310 53 98
E-Mail: hui.zhang AT psi.ch
-----Original Message-----
From: opal-request AT lists.psi.ch [mailto:opal-request AT lists.psi.ch] On Behalf 
Of James Gerity
Sent: Dienstag, 13. Juni 2017 23:46
To: Opal AT lists.psi.ch
Subject: [Opal] [bug?] Probe data is not always saved

All,
  It seems that any tracker error raised in the ParallelCyclotronTracker will 
prevent the finalization of probes in ParallelCyclotronTracker::execute().

This function calls one of several Tracker_*() functions that may throw an 
error and when this is the case, the end of execute() is skipped, so that 
finalise() is not called for each element in the selected beamline, including 
any probes that might have stored data.

I've locally modified my working copy of OPAL (1.4.0-rc3, but at a glance the 
execute() function looks similar in the development
version) to catch the thrown OpalException, finalise() the entire beamline, 
and re-throw the exception. For the simulations I'm running, it is most 
convenient to track particles until they are "lost" rather than a particular 
duration, and it seems to me that the general end-user would expect the 
probes to output events seen before the error, rather than discarding all of 
this data.

Thanks,
James