[Halld-offline] Truth info from BCAL hadronic showers

[Will Levine]

Hi Richard,
Thanks for the information. I guess that means when that when we see
multiple TruthShower's in one event the pion must have interacted
before entering the BCAL.

One thing to note is that many of the late hits are located near the
original shower location. If these are from pion decays it must mean
that the pions have stopped inside the detector. I guess this is
plausible, especially for tracks that enter the detector at a more
oblique angle. Does that sound right? Can anyone think of an
explanation for why we don't see a similar effect in the FCAL?

Will

On Thu, May 29, 2014 at 6:47 PM, Richard Jones
<richard.t.jones at uconn.edu> wrote:
> Hello Will and all,
>
> Once a primary particle has entered the BCAL and had its TruthShower
> recorded, it is marked with a spot of red dye (colloquially). Any
> secondaries that are generated from interactions by that particle inherit
> its red spot, even if they escape from that module and enter another one.
> However, these late interactions typically are generated by delayed decays
> of muons from pi decays, aren't they?  Typically that is what makes late
> hits in a calorimeter, if my memory serves me correctly.
>
> -Richard J.
>
>
> On Thu, May 29, 2014 at 6:32 PM, Will Levine <wilevine at andrew.cmu.edu>
> wrote:
>>
>> Hi offline,
>> Following up on the issue of "late" energy deposition in hadronic
>> showers in the BCAL.
>>
>> There are two different ways that BCAL truth information from hdgeant
>> is stored: these can be accessed in JANA from the DBCALTruthShower and
>> the DBCALTruthCell objects. The code that stores this information is
>> in hitBarrelEMcal() in
>> sim-recon/src/programs/Simulation/HDGeant/hitBCal.cc
>>
>> As I understand the code, DBCALTruthShower records every particle that
>> geant tracks thru the BCAL (with energy greater than 1 MeV). One
>> DBCALTruthShower for each unique particle in the BCAL. This includes
>> all secondary shower particles. The particle type, initial energy, and
>> initial position in the BCAL is recorded for each particle.
>>
>> DBCALTruthCell just records the energy deposited in a given BCAL cell
>> without recording which particle was responsible for the energy.
>> (Again this is "truth" information, before any detector resolution or
>> readout effects are incorporated).
>>
>> These two sources of information are not always tremendously helpful.
>> For example in one single-pion event that has some characteristic
>> "late hits", we see the following DBCALTruthShower's:
>>
>> DBCALTruthShower:
>>  ptype: track: primary:    phi:      r:     z:     t:     p:     E:
>> -------------------------------------------------------------------
>>      8      1        1  -1.863  65.042  185.3  4.780  0.571  0.588
>>
>> Only the primary pion is recorded. There is no record of any secondary
>> tracks. But when we look at the TruthCell's in the same event:
>>
>> DBCALTruthCell [truncated]:
>>  module: layer: sector:     E:       t: zLocal:
>> -----------------------------------------------
>>      34      1       1  0.006    71.31    -6.0
>>      34      1       3  0.027     4.87   -24.4
>>      34      1       4  0.002     4.79   -26.5
>>      34      2       1  0.006    33.59   -16.9
>>      34      2       2  0.018     5.07   -19.6
>>      34      2       3  0.013     4.98   -21.7
>>      34      3       1  0.020    28.91   -15.4
>>      34      3       1  0.005  4301.28   -19.1
>>      34      3       2  0.023     5.19   -16.6
>>      34      4       1  0.029     6.45   -13.1
>>      34      4       1  0.019    73.07   -13.0
>>      34      4       1  0.004  2219.77   -13.3
>>      34      4       1  0.039  4301.12   -15.0
>>      34      5       1  0.017     8.24    -9.6
>>      34      5       1  0.001  4301.19   -17.1
>>      34      7       1  0.011    10.44   -21.4
>>
>> The time is in the second-to-last column. The "on-time" hits have t ~
>> 5 ns. Where are all the late hits coming from? It is not clear. There
>> must be some tracks that are not recorded in the TruthShower info.
>>
>> Even in events with a more extensive record of secondary tracks it's
>> not clear what is responsible for a late hit:
>>
>> DBCALTruthShower:
>>  ptype: track: primary:    phi:      r:     z:     t:     p:     E:
>> -------------------------------------------------------------------
>>      8      1        1  -2.072  65.042  186.4  4.812  0.572  0.589
>>     13     22        0  -2.083  65.969  188.5  5.185  0.284  0.982
>>     14     21        0  -2.083  65.969  188.5  5.185  0.040  0.939
>>     13     20        0  -2.083  65.969  188.5  5.185  0.173  0.955
>>      3     19        0  -2.081  65.814  188.1  4.879  0.005  0.005
>>      3     19        0  -2.083  65.851  188.2  4.884  0.002  0.002
>>      1     19        0  -2.083  65.852  188.2  4.884  0.001  0.001
>>
>> Any ideas?
>>
>> Will
>> _______________________________________________
>> Halld-offline mailing list
>> Halld-offline at jlab.org
>> https://mailman.jlab.org/mailman/listinfo/halld-offline
>
>