sPHENIX EMCal discussion

[Craig Woody <woody AT bnl.gov>]

HI Joe,
  Very nice work ! I agree with John that this is certainly a good way 
to show what we expect the calorimeter resolution to be for isolated 
showers, which is something that we want to include in our CDR. It's 
nice to see that after the position dependent correction, the resolution 
for electrons and positrons agrees very well with the simulation with a 
flat light collection response. The only thing I would like to point out 
is that we have to be careful how we present this when we compare this 
to our test beam data. From your last analysis where you refit the 
peaks, the resolution we measured for electrons, including only the 
light guide boundaries, was consistent with the simulation with the flat 
light collection response (actually a bit better), implying that the 
correction got us down to what we expected from the simulation, but when 
the scan also included the block boundaries, it got much worse 
(15.6%/SQRT(E) + 4.3% plus the beam momentum spread). This implies that 
the correction is not working as well in this case, and that the block 
boundaries are really the main source of our non-uniformities in the 
energy response. I believe there is some model of the block boundaries 
in the simulation, but I'm not sure how realistic it is. Of course, we 
know that the blocks we tested in the test beam this year were very bad 
in this respect and that we expect the new blocks to be better, but we 
don't really know how much better they will actually be. We do try and 
explain this in the CDR, but we also have to be careful about comparing 
these results to our test beam data and drawing conclusions about what 
our energy resolution will finally be.

Cheers,
Craig

On 6/1/2017 10:29 AM, John Haggerty wrote:
> Joe,
>
> Thanks, that's exactly what I was thinking of. The calorimeter big 
> guys should comment, but it seems to me that slide is the complete 
> answer to the question, "What is the resolution of the EMCAL in 
> sPHENIX for single isolated particles in simulation?"  Of course, 
> there are many other resolutions that matter to us, like what any of 
> these plots would look like when embedded in minbias events and 
> whatnot, but I think this is the kind of clearly documented 
> performance plot that Gunther talked about.
>
> Perhaps putting this in a one or two page document that collects the 
> technical data about it (what data was used, what detector models were 
> turned on, and so on), maybe even in a git repository with the code, 
> would assure us that we know what it is, where it comes from, and what 
> might change as our understanding of the detector evolves.
>
> Before you go to that trouble, we should agree on a way of 
> systematically doing it that we all agree on, but this is very good.
>
> On 6/1/17 9:59 AM, Joe Osborn wrote:
> > Dear John and all,
> >
> > Attached is, what I think is, the plot you requested. Please let me 
> > know if you have any comments about it. I averaged the position 
> > corrected resolutions over eta since they were very similar and so 
> > that each panel would not be extraordinarily cluttered.
> >
> > To Jin: I will get started on a recalibration module with the 
> > calibration constants.
> >
> > Joe
> >
> >
> >
> > ---------------------------------------
> >
> > Joe Osborn
> > Ph.D Candidate
> > University of Michigan
> > jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>
> > (859) 433-8738
> >
> > On Wed, May 31, 2017 at 12:26 PM, John Haggerty <haggerty AT bnl.gov 
> > <mailto:haggerty AT bnl.gov>> wrote:
> >
> >     Joe,
> >
> >     Very nice work.  For the next round of the CDR, I'm thinking you
> >     could contribute these plots:
> >
> >     1) Resolution with "ideal" light collection
> >     2) Uncorrected resolution with position dependent light collection
> >     3) Position corrected resolution
> >     4) Position corrected resolution with some random channel-to-channel
> >     "calibration" errors
> >
> >     I think you have the first three, which would look handsome on 2x2
> >     canvases, one for e+, one for e-, one for photons.  Does that sound
> >     like a good idea?
> >
> >     Also, another thing we have to revise is the discussion of sampling
> >     fraction; it used to be 2.4%, but I think it is more like 2% now,
> >     and I'm not quite sure how it varies in eta.
> >
> >     On 5/31/17 9:11 AM, Joe Osborn wrote:
> >
> >         Dear EMCalers,
> >
> >         Following Jin's suggestion, I implemented a leading order
> >         position dependent recalibration on the energy response for
> >         photons, electrons, and positrons. The results are attached in
> >         this email.
> >
> >         Please note that the "before recalibration" plots are not the
> >         exact same as what I sent before as I was inadvertently only
> >         using 10% of the simulation that Chris produced (whoops). The
> >         results here are using the entire single particle production.
> >         The position dependent recalibration reduces the constant term
> >         by 1-2% for each eta bin.
> >
> >         Thanks,
> >
> >         Joe Osborn
> >
> >
> >
> >         ---------------------------------------
> >
> >         Joe Osborn
> >         Ph.D Candidate
> >         University of Michigan
> >         jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>
> >         <mailto:jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>>
> >         (859) 433-8738 <tel:%28859%29%20433-8738>
> >
> >         On Sun, May 28, 2017 at 10:13 AM, Joe Osborn <jdosbo AT umich.edu
> >         <mailto:jdosbo AT umich.edu> <mailto:jdosbo AT umich.edu
> >         <mailto:jdosbo AT umich.edu>>> wrote:
> >
> >              Hi John,
> >
> >              Chris sent a couple of emails out to the software lists,
> >         but I guess
> >              not the other lists. It might be too late as the BBQ might
> >         already
> >              be fired up, but for anyone who wants to take a look the G4
> >         hits
> >              files are located in the following directory:
> >
> >              /sphenix/data/data02/review_2017-08-02/
> >
> >              Joe
> >
> >
> >
> >              ---------------------------------------
> >
> >              Joe Osborn
> >              Ph.D Candidate
> >              University of Michigan
> >         jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>
> >         <mailto:jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>>
> >         (859) 433-8738 <tel:%28859%29%20433-8738> <tel:(859)%20433-8738>
> >
> >              On Fri, May 26, 2017 at 4:04 PM, John Haggerty
> >         <haggerty AT bnl.gov <mailto:haggerty AT bnl.gov>
> >              <mailto:haggerty AT bnl.gov <mailto:haggerty AT bnl.gov>>> wrote:
> >
> >                  Joe,
> >
> >                  Thanks to Joe, Jin, and Chris for these results.  
> > There is
> >                  obviously some bouncy behavior that seems a little odd,
> >         but I
> >                  know that even in very simple cases, getting "the
> >         resolution" at
> >                  the few percent level is not as simple as it sounds.
> >
> >                  Just to be clear--this is with the right detector 
> > material
> >                  budget in front of the EMCAL, all events from 
> > (0,0,0), and
> >                  Sean's light collection map in every tower?
> >
> >                  Probably as you say nobody's going to have time 
> > between the
> >                  barbecue this weekend and the upcoming barbecues at the
> >         lab, but
> >                  you might ask Chris to post their location to the wiki
> >         and the
> >                  emcal and hcal lists.
> >
> >                  On 5/26/17 3:37 PM, Joe Osborn wrote:
> >
> >                      Dear EMCalers,
> >
> >                      As Jin presented in the simulations/EMCal meeting
> >         this week,
> >                      he has updated the EMCal simulations with the tower
> >         tilting
> >                      in azimuth and polar directions, amongst other
> >         changes. With
> >                      the simulations code tagged, Chris produced single
> >         particle
> >                      simulations that people can play with before we 
> > start
> >                      producing large batches of simulations.
> >
> >                      Attached are the resolution of the EMCal for 
> > photons,
> >                      electrons, and positrons in several different eta
> >         bins. Just
> >                      to be clear, the single particles were thrown for 9
> >                      different energies in the four different eta 
> > regions
> >                      surrounding the values quoted in my plots (i.e. 
> > eta=0
> >                      corresponds to truth particles being thrown in
> >         +/-0.05 units
> >                      of pseudorapidity around 0, same for eta=0.3,0.6,
> >         and 0.9).
> >
> >                      Any comments would be great, or perhaps everyone
> >         will be too
> >                      busy enjoying the long weekend in which case we can
> >         also
> >                      discuss them at the EMCal meeting next week.
> >
> >                      Thanks,
> >
> >                      Joe
> >
> >                      ---------------------------------------
> >
> >                      Joe Osborn
> >                      Ph.D Candidate
> >                      University of Michigan
> >         jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>
> >         <mailto:jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>>
> >                      <mailto:jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>
> >         <mailto:jdosbo AT umich.edu <mailto:jdosbo AT umich.edu>>>
> >         (859) 433-8738 <tel:%28859%29%20433-8738> 
> > <tel:%28859%29%20433-8738>
> >
> >
> > _______________________________________________
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> >
> >
> >
> >                  --         John Haggerty
> >                  email: haggerty AT bnl.gov <mailto:haggerty AT bnl.gov>
> >         <mailto:haggerty AT bnl.gov <mailto:haggerty AT bnl.gov>>
> >                  cell: 631 741 3358 <tel:631%20741%203358>
> >         <tel:631%20741%203358>
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> >
> >
> >
> >
> >
> >     --     John Haggerty
> >     email: haggerty AT bnl.gov <mailto:haggerty AT bnl.gov>
> >     cell: 631 741 3358 <tel:631%20741%203358>