[Halld-cal] Newer plots

[Mark Macrae Dalton]

Hi Tegan,

I completely agree with Elton that this back-to-basics study is necessary.  

Best,
Mark Macrae Dalton

--
Staff Scientist, Jefferson Lab
office: +1 757 269 6931
mobile: +1 757 849 2929

> On Jun 4, 2015, at 6:08 PM, Elton Smith <elton at jlab.org> wrote:
> 
> Hi Tegan,
> 
> I was looking over David's shoulder when he was looking at the code to see where/how MC energy was converted to hits. It appears that the geant generated energies are passed onto mcsmear where they are converted to hits simply by applying an attenuation factor. (The only other parameter/constant involved is the ceff, which does no affect energies). By using the variation=mc for both mcsmear and hd_root, the programs should be getting the same value for generation and reconstruction from ccdb.
> 
> There is one other possibility for loosing energy (besides genuine leakage) and that is a threshold that is applied in mcsmear. If I remember correctly, hits are only passed onto to the output if the energy in a cell is greater than 3.5 MeV. On average this corresponds to 3.5 MeV/0.03 MeV/integral count = 116 integral counts / 15 integral counts/peak counts = 7.8 counts. This is in the ball park, but for our daq threshold of 5 counts, we should have 75 integral counts * 0.03 MeV/int count = 2.25 MeV.
> 
> I think we need to verify that the simulated hits add up to the entire energy deposited by geant into the active volume of the detector. My suggestion would be to
> 1) For testing, set the threshold value to 0.
> 2) Generate photons with a fixed energy (pick 1 GeV) and fixed angle (start at 90 deg, i.e. perpendicular to the BCAL) and shoot these into the BCAL.
> 
> - Check that all the energy generated into the active volume make their way though mcsmear into the output file.
> - Turn the threshold on (set to 2.25 MeV) and compare.
> - Consider whether (non-linear) corrections should be applied to the deposited energy or it is sufficient to scale outputs to match the input energy.
> - Check the width of the energy distribution to see if it is consistent with our expectation, i.e. fluctuations from sampling, photostatistics, pedestal width, etc. If not, adjust parameters in mcsmear to match expectations.
> - Repeat exercise with photons at other angles.
> - Take a look at the pi0 peak again, but it should match up. (If not one needs to look into position reconstruction).
> 
> I know... I have just outlined a project, not just a task.
> 
> Cheers, Elton.
> 
> 
> 
> 
> 
> Elton Smith
> Jefferson Lab MS 12H3
> 12000 Jefferson Ave STE 4
> Newport News, VA 23606
> (757) 269-7625
> (757) 269-6331 fax
> 
> On 6/4/15 5:24 PM, beattite wrote:
>> Yes, both the mcsmear and hd_root commands were done while the variation=mc variable was set.
>> 
>> 
>> On 04.06.2015 15:17, David Lawrence wrote:
>>> Hi Tegan,
>>> 
>>>  Just double checking that you used variation=mc when you ran
>>> mcsmear as well as
>>> when you ran the reconstruction.
>>> 
>>> Regards,
>>> -David
>>> 
>>> On Jun 4, 2015, at 3:44 PM, beattite <beattite at uregina.ca> wrote:
>>> 
>>>> Hello.
>>>> 
>>>> Here are the mcsmear comparison plots using the variation=mc variable.  There are two files.  One is the mass spectra using cluster energies, the other is using shower energies.<BCAL_inv_massEcluster.pdf><BCAL_inv_massEshower.pdf>_______________________________________________
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