[Halld-cal] updated study of Fcal response in MC

[Richard Jones]

Ilya,

We just learned that the combination of lead glass and lucite contributions
to the light yield is a particularly simple one, with the coefficients of
the lucite part being zero.

-Richard

On Wed, Mar 13, 2019 at 1:41 PM Sean Dobbs <sdobbs at fsu.edu> wrote:

> Hi Richard,
>
> One correction:  by default the energy deposited in the light guides
> is not added to the main block energy in mcsmear, because its effect
> has not yet been studied in detail.
>
> ---Sean
>
> On Wed, Mar 13, 2019 at 1:38 PM Richard Jones <richard.t.jones at uconn.edu>
> wrote:
> >
> > Hello Ilya,
> >
> > I agree, although I want to add the light is generated separately in the
> lead glass blocks and the lucite light guides, in the MC simulation. These
> two are combined into a single light output in mcsmear, in a treatment that
> is the same for both hdgeant and hdgeant4.
> >
> > -Richard J.
> >
> > On Wed, Mar 13, 2019 at 12:58 PM Ilya Larin <ilarin at jlab.org> wrote:
> >>
> >>
> >> Hi Liping,
> >>
> >>
> >> I guess final linearity corrections might be involved in
> >>
> >> mcsmear and reconstruction to explain the observed
> >>
> >> positive deviation in reconstructed energy at high energy end.
> >>
> >> I don't think it is an effect of light guides or limited
> >> transparency of the blocks.
> >>
> >>  Regards,
> >> Ilya
> >>
> >> ________________________________
> >> От: Gan, Liping <ganl at uncw.edu>
> >> Отправлено: 13 марта 2019 г. 12:50
> >> Кому: Richard Jones; Ilya Larin
> >> Копия: Liping Gan; Matthew Shepherd; halld-cal at jlab.org
> >> Тема: Re: updated study of Fcal response in MC
> >>
> >>
> >> Hi, Richard,
> >>
> >>
> >> In your result, the energy deviation for the reconstructed photon in
> FCAL reaches more than 100 MeV. I would like to ask Ilya to comment on this
> since he has done a lot of simulations on calorimeter.
> >>
> >>
> >> Liping
> >>
> >>
> >>
> >> ________________________________
> >> From: Richard Jones <richard.t.jones at uconn.edu>
> >> Sent: Tuesday, March 12, 2019 2:16 PM
> >> To: Gan, Liping
> >> Cc: Liping Gan; Matthew Shepherd; halld-cal at jlab.org
> >> Subject: Re: updated study of Fcal response in MC
> >>
> >> Hello Liping,
> >>
> >> The response of the calorimeter itself in the MC does not have these
> two inflection points that you see in these plots. Those are coming from
> the interaction between the non-linear response in the simulation coupled
> with the (non-equivalent) non-linear corrections being applied in mcsmear
> and the cluster energy reconstruction. This plot shows the net effect of
> all 3 (MC + mcsmear + recon).
> >>
> >> -Richard
> >>
> >> On Tue, Mar 12, 2019 at 1:13 PM Gan, Liping <ganl at uncw.edu> wrote:
> >>
> >> Hi, Richard,
> >>
> >>
> >> Thanks for the excellent result. I just wonder if there is any
> explanation for the small bump at 1.5-2.5 GeV in you plots? Thanks!
> >>
> >>
> >> Liping
> >>
> >> ________________________________
> >> From: Richard Jones <richard.t.jones at uconn.edu>
> >> Sent: Tuesday, March 12, 2019 10:37:29 AM
> >> To: Liping Gan; Matthew Shepherd
> >> Cc: halld-cal at jlab.org
> >> Subject: updated study of Fcal response in MC
> >>
> >> Hello Liping and all,
> >>
> >> At your suggestion, I went back and redid my study of reconstructed
> showers in the FCAL from MC, comparing hdgeant and hdgeant4, this time
> covering a larger energy range up to 8 GeV. For the results, see the latest
> document uploaded to docdb.
> >>
> >>
> https://gcc01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fhalldweb.jlab.org%2Fdoc-private%2FDocDB%2FShowDocument%3Fdocid%3D3852&data=02%7C01%7Challd-cal%40jlab.org%7C8e06c29b6cc34350d8c208d6a7db8e2e%7Cb4d7ee1f4fb34f0690372b5b522042ab%7C1%7C0%7C636880958759431416&sdata=sCzheymchq56OgJ5H7pyD0A7ZIUXW58iIxPpq%2FzsQeg%3D&reserved=0
> >>
> >> Here is a summary of what I found.
> >>
> >> I found a small bug in my fitting code that shifted the Ereconstructed
> down by 16 MeV relative to the generated in my earlier studies. This made
> the negative y-intercept in the Ereconstructed vs Egenerated appear worse
> than it actually is.
> >> I adjusted the output from shower particles in hdgeant4 relative to
> hdgeant down by 0.8% as we discussed a the last calorimeter meeting. This
> change is visible in the new results. I now claim that the agreement in the
> shower energy response between hdgeant and hdgeant4 is very good.
> >> With the new larger simulated energy range, my statistics of 100K
> events total is limiting my statistical accuracy in studying the
> non-linearity. Since there is no visible variation with polar angle seen in
> these individual plots, I added at the end a plot with the full statistics
> over the range 3-11 degrees, which has less statistical scatter and reveals
> the nonlinear behavior better.
> >> Above 4 GeV there is a very large rise in the reconstructed energy.
> Overall the nonlinear correction needs work at both the low and high energy
> ends of the Fcal spectrum.
> >>
> >> -Richard Jones
> >
> > _______________________________________________
> > Halld-cal mailing list
> > Halld-cal at jlab.org
> >
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