[Halld-offline] new itrack info saved in MC hddm truth tags

[Justin Stevens]

Hi All,

To close the loop on 2), the decay vertices of hadrons which make it through the BCAL/FCAL and decay in the magnet iron, etc. are no longer being stored in the hddm record.

-Justin

New Revision: 16009

Modified:
  trunk/sim-recon/src/programs/Simulation/HDGeant/gustep.F
Log:
As suggested by Richard: add additional requirement, ISTORY.eq.0, when tagging secondaries for saving (set iflgk) and when recording vertices in hddm record.

On Oct 23, 2014, at 12:44 PM, Justin Stevens wrote:

> Hi Richard,
> 
> Thanks again for updating the truth tags.  After testing this out a bit, I have a couple comments about all the changes made lately:
> 
> 1) You said that the "itrack" index is set to -1 for secondaries.  Just to clarify, this is _not_ true for secondaries from a particle decay.  So B/FCAL truth showers due to photons from pi0 decays are indexed to the MC record (ie. DMCThrown) as desired.
> 
> 2) This is related to the changes you made to gustep.F to check if secondaries are produced in the BCAL, FCAL, and CAVE.  Before there was a requirement on the radius of the decay vertex to be R < 65 cm to store the secondary vertex.  With this removed we're now storing decay vertices in hddm which occur beyond the BCAL (ie. R > 90 cm).  We could remove some of these extraneous secondaries which appear in DMCThrown by reinstating some decay vertex radius (and z) requirement, or maybe you have another suggestion to reduce these?  
> 
> Thanks,
> Justin
> 
> On Oct 21, 2014, at 8:23 AM, Richard Jones wrote:
> 
>> Hello all,
>> 
>> As requested by Justin, I have just checked in an update to the simulation and hddm decoding libraries in sim-recon to introduce itrack information for TruthShower and TruthPoint tags. Formerly only a "track" index was provided. 
>> 	• "track" - a unique ID assigned by geant to each particle it tracks, including primaries and secondaries generated outside the calorimeters or cave.
>> 	• "itrack" - a lookup index that can be used to find the particle in the MC record that gave rise to the tracking point or shower, or -1 if it is a secondary.
>> With this change, you get both track and itrack for each TruthPoint and TruthShower. The new code is backward-compatible, meaning that hddm files that were generated prior to this update will still be readable by the new code (albeit with itrack=0 being read everywhere it was missing before) and that hddm files generated using the new code are still readable by old consumer binaries (albeit without access to the new itrack info).
>> 
>> I am now propagating all of these changes into the commissioning branch - what a pain!!
>> 
>> -Richard J.
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> 
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