[Halld-cal] MC Michel Spectra selection cuts

[semenov at jlab.org]

Will:

I still need some clarification: In the item 1 (in your e-mail), you wrote
that you require at least one 2-sided point, and in the item 2, you said
that you require at least two 2-sided points... You are talking about the
same points, isn't you?

So, how many 2-sided points you required: at least one or at least two?

Another question is about the spectra in the readout cells: What cell you
are interesting in? Irina has the muon decay points that are spread over
whole volume of BCAL. I can make 48*4*4=768 spectra in each cell without
any connection to the decay point. Alternatively, I can try to make the
spectrum of the energy deposition in the cell where the decay is happened.
Or you need something else? Please let me know.

Thank you,
Andrei


> Hi Andrei,
>
> 1. I require that there is at least one 2-sided point (with a z position
> from the up/down time difference) and do an energy weighted average in z
> to get some average z-position for the electron z-position and apply that
> averaged z-position to all 1-sided hits that are close by.
>
> 2. I require that we make at least 2 2-sided points in the electron energy
> spectrum. The less than 4 module of separation cut applies to 1-sided hits
> and 2-sided points. I plan to try and change this condition next week
> after DNP ends though.
>
> 3. I think that the total energy deposition spectra is more useful for
> calibration, but the spectra for each readout cell is interesting and
> could be used as well.
>
> Will
>
>> Elton and Will:
>>
>> I need a few clarifications:
>>
>> 1. How you reconstruct the energy in the cell for 1-sided case?
>>
>> 2. About the condition to have at least 2 but less than 4 modules with
>> energy depositions: Do you count 1-sided energy depositions here?
>>
>> 3. Do you need the spectra for each readout cell or you need the spectra
>> for the total energy deposition (above threshold) in the BCAL?
>>
>> Thank you,
>> Andrei
>>
>>>
>>> Hi Andrei,
>>>
>>> Following our discussion at the reconstruction meeting yesterday, it
>>> would be nice to be able for Will to compare his electron spectra with
>>> the Michel generated MC.
>>>
>>> Thresholds: The flash threshold is 5 counts above threshold. This
>>> corresponds to an attenuated energy of Th0=2.3 MeV using the following
>>> constants:
>>> Th0 = 5 peak counts * 15 int cts/peak * 0.03 MeV/int count
>>> Due to attenuation lambda, the threshold is in fact higher depending on
>>> the position of the hit, i.e.
>>> Energy Thresh (z) > Th0 x exp [(L/2 + z)/lambda]; upstream
>>> Energy Thresh (z) > Th0 x exp [(L/2 - z)/lambda]; downstream
>>> where z is measured relative to the center of the module and increases
>>> downstream. For the attenuation length you can check what is currently
>>> in ccdb. See for example
>>> https://logbooks.jlab.org/files/2015/09/3352084/ccdb_get_attenuation_parameters_col0.pdf
>>> You can either use an average or a range based on the measured
>>> distribution.
>>>
>>> It would be nice to see the spectra by varying the threshold Th between
>>> 0.5xTh0 and 2xTh0.
>>>
>>> You also mentioned that we might consider including selection cuts,
>>> which Will is using in his analysis. He uses the following selection
>>> cuts:
>>> 1. late time hit cut
>>> 2. requirement that energy is deposited in at least 2 channels
>>> 3. the electron energy is deposited in less than 4 modules
>>> 4. at least one point object is in the distribution.
>>>
>>> Cuts 1 and 3 should all be satisfied by bona fide events, so no need to
>>> add to MC.
>>> Cut 2 will likely be relaxed as the analysis evolves, so no need to add
>>> at this time.
>>>
>>> The only cut, which should be included, is #4. This requires that at at
>>> least one cell have a hit on both ends, i.e. the threshold requirement
>>> (above) be satisfied for at least one cell for both upstream and
>>> downstream hits.
>>>
>>>
>>> Send questions or clarifications to me or Will.
>>>
>>>
>>> Thanks, Elton.
>>>
>>>
>>> Elton Smith
>>> Jefferson Lab MS 12H3
>>> 12000 Jefferson Ave STE 4
>>> Newport News, VA 23606
>>> (757)269-7625
>>> (757)269-6331 fax
>>> _______________________________________________
>>> Halld-cal mailing list
>>> Halld-cal at jlab.org
>>> https://mailman.jlab.org/mailman/listinfo/halld-cal
>>>
>>
>>
>>
>