Re: Geometries for 2008 DC Review

["Kornicer, Mihajlo" <mikornic@indiana.edu>]

Hi David,

thanks for instructions, I had one hddsGeant3.F and I did clean objects
but there were all 3 Hdds... I grabbed from wiki in the same directory:)

I'll make new plots with more statistics and hopefully this will be resolved.

Regards,
Mihajlo

>
> Hi Matt,
>
>    Thanks for those plots. Just to clarify though, my comment was
> aimed at the *relative* difference in the "summer 2007" and the
> "winter 2007" efficiency plots compared to the *relative* difference
> in the radiation length scans. If I look at the black markers on
> Mihajlo's plot for angles greater than 13 degrees, there are 2 very
> clear flat areas with valleys in between. The valleys, I assume, are
> due to the frames and their depths are correlated with the amount of
> material in the frames. If I look at the radiation length scans, I
> can see the peaks for the new geometry are about 1/3 to 1/4 as high
> as for the old geometry. This makes me think I should see valleys
> that are 1/3 to 1/4 as deep in the red markers as in the black.
> Granted, these may be small, but if I focus only on the black markers
> in Mihajlo's plot and visual valleys that are 1/3 shallower, I think
> I should still see them easily.
>
> Your plots are interesting since if I look at the pair on the right
> (0-120 degree range), I think I can see the structure maps from the
> top to the bottom. For the pair on the left though, the bottom plot
> looks more like statistical fluctuations than any real reflection of
> the structure. It would be interesting to see that plot with a lot
> more statistics.
>
> Regards,
> -David
>
> Matthew Shepherd wrote:
>>
>> Hi Mihajlo and Dave,
>>
>> On Jan 24, 2008, at 12:06 PM, David Lawrence wrote:
>>
>>> I do see the positions and heights of the peaks have changed quite
>>> a bit. But, not so much so that I expect to see as flat of a
>>> distribution as I see in your plots. I could be wrong though, but
>>> I'm hoping when you re-run with the exact geometries I'm using, we
>>> sill consistent pictures.
>>
>> I suggest Mihajlo generate plots of both conversion probability and
>> efficiency to provide a definitive answer since I suspect the
>> confusion is in the distinction between these two.  Attached are
>> similar plots for only the current geometry.  Conversion probability
>> is directly related to David's radiation length scans, but
>> efficiency is not necessarily since converted photons can be
>> reconstructed if secondary particles still form a nice cluster.  You
>> can get an idea of the magnitude of this effect by comparing the
>> attached plots.  In the ring region the efficiency is up around
>> 85-90% but the conversion probably is still in the 20-30% range.
>>
>> -Matt
>
> --
>
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>  David Lawrence Ph.D.
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