sPHENIX EMCal discussion

["Sickles, Anne M" <sickles AT illinois.edu>]

Hi John & Don,

I think it would be interesting to try what John suggests for the prototype 
and its simulations (since we have the density by module and we’ll know the 
module location).   I know Sean and Craig have tried to put the best modules 
toward the center of the prototype; this will minimize the density variations 
at the core of showers so it may be that this isn’t a large effect right now. 
 Jin, is it possible to vary the module density within the current simulation 
framework?

As to the module tracking, I agree with Don.  We were surprised to find that 
THP hadn’t kept track of this kind of information at production time and we 
will need it on all future module productions.  For the Illinois modules, we 
have set up a google spreadsheet which works fine for the number of modules 
we’ve made currently, but we’ll need something different as the number of 
modules increases.

Anne


> On Feb 29, 2016, at 8:56 AM, dlynch AT bnl.gov wrote:
> 
> Hi all,
> 
> My 2 cents, we should be able to trace the THP modules back to their 
> production. If THP is not already doing so, they should be tracking each 
> module with a route card so that variations in materials, procedures, 
> assembly techniques, and personnel can be tracked. This is basic QA and not 
> just a good idea but generally a requirement in the QA section of BNL 
> Purchase Orders.
> 
> 
> -Don
> 
> From: <sphenix-emcal-l-bounces AT lists.bnl.gov> on behalf of "Sickles, Anne 
> M" <sickles AT illinois.edu>
> Date: Friday, February 26, 2016 at 8:16 PM
> To: Gabor David <david AT bnl.gov>
> Cc: "sphenix-emcal-l AT lists.bnl.gov" <sphenix-emcal-l AT lists.bnl.gov>
> Subject: Re: [Sphenix-emcal-l] Density plot
> 
> Hi Dave, John & Gabor,
> 
> The Illinois modules are numbered according to the production sequence so, 
> yes, in general we are getting higher density with time.  However there are 
> a couple of features.  Between module 6 & 7 there was a change in the 
> filling procedure for the tungsten and you can see a corresponding increase 
> in density.  Additionally the final eight Illinois modules were produced 
> with a different batch of tungsten powder from the prior modules and a 
> slightly different mold.  These modules were all produced this week under 
> essentially identical conditions and thus I think the observed density 
> variation is inherent in the (current) procedure.  The effect of the 
> tungsten powder batch is something we are looking into in more detail; at 
> this point we can only say that not all tungsten powder is the same…
> 
> For the THP modules the numbers don’t mean anything about the production 
> since the numbers were assigned in Illinois rather than at THP at 
> production time.  The density variation is a point of concern, but I don’t 
> have a quantitative number of the size of density variation we can 
> tolerate.  Obviously we can take steps to correct for it or model it with 
> simulation, but we also need to build a density range into our QA criteria 
> for the modules themselves.  That is something I hope to understand better 
> with the test beam.
> 
> Best,
> Anne
> 
>> On Feb 26, 2016, at 5:29 PM, Gabor David <david AT bnl.gov> wrote:
>> 
>> On Fri, 26 Feb 2016, Lajoie, John G [PHYSA] wrote:
>> 
>> Hi, John,
>> 
>>> Hi Vera,
>>>     Very nice plot!
>>>     The THP points in particular had me wondering if there is a limit to 
>>> the
>>> variation of the density that you can tolerate?  I would expect that a
>>> module-to-module variation in the density (of the absorber) would lead to 
>>> a
>>> variation in the effective sampling fraction, which could degrade the
>>> effective energy resolution.  I suppose if you knew the density of each
>>> module you could make a correction?
>> 
>> wild guess: yes, and two different ways.
>> 1/ have the same density in each module in the simulation,
>> but at the end correct the visible signal in each tower (such a
>> "calibration of the simulation output" is not unheard of, actually
>> in some sense we are doing it even now)
>> 2/ get different densities for different modules in GEANT4
>> (just kidding; nightmare!)
>> 
>> Maybe a first good question to ask would be to compare
>> the simulated response in two modules with densities corresponding
>> to the two ends of the current density distribution.
>> 
>> 2 cents :-)
>> 
>> Gabor
>> 
>>> John
>>> On 2/26/2016 4:24 PM, Loggins, Vera wrote:
>>>      Hi all,
>>> I just wanted to share the density plot vs. module number that we have
>>> at UIUC.  I have plotted this along with THP's numbers.
>>> Have a good weekend,
>>> Vera
>>> --
>>> John Lajoie
>>> Professor of Physics
>>> Iowa State University
>>>  
>>> (515) 294-6952
>>> lajoie AT iastate.edu
>>> Facebook LinkedIn
>>> Contact me: Skype john.lajoie
>>> 
>> 
>> -- 
>> Gabor David  (david AT bnl.gov)
>> Brookhaven National Laboratory
>> Physics Department, Bldg 510/c
>> UPTON NY 11973
>> Tel: (631)344-3016
>> FAX: (631)344-3253_______________________________________________
>> Sphenix-emcal-l mailing list
>> Sphenix-emcal-l AT lists.bnl.gov
>> https://lists.bnl.gov/mailman/listinfo/sphenix-emcal-l
> 
> --------------------------------------------------------------
> Anne Sickles
> Assistant Professor, Department of Physics
> University of Illinois at Urbana-Champaign
> --------------------------------------------------------------
> 
> 
> 
> 
> 
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