[Castor-users] Fwd: artifacts in the reconstruction

[Alessandro Pilleri]

Dear Simon,
thank you for your answer.

I used the GateRoot converter to create the data file in histogram mode and
to automatically generate the geometry (-geo parameter). It automatically
added the 135 deg min angle difference in the .geom file.
I thought the min angle difference was applied in the loop over the data,
so I tried to change it in the .geom file.  By the way, now  I created two
different data files changing the digitizer option in the gate macfile to
change the coincidence scheme and the sensitivity images do look different.

For the application of the normalization coefficients, in histogram mode,
do I have to manually modify the datafile to change the normalization
coefficients of the events from 1 to the appropriate coefficient?

Alessandro

On Wed, Dec 16, 2020 at 11:42 AM STUTE Simon <simon.stute at chu-nantes.fr>
wrote:

> Hi Alessandro,
>
>
> The artifacts are totally normal if you do not apply a normalization
> correction, especially with low number of detector panels.
>
>
> As for the min angle difference, did you let CASToR compute the
> sensitivity image in both cases (135 and 180) ? Are they different ?
>
> The min angle difference is not apply in the loop over the data, so it
> should be applied by yourself when building the datafile.
>
> Also, how did you build the geometry of your scanner, from your own LUT
> file or using the GATE converter ?
>
>
> By the way, your emails successfully reached the mailing list.
>
>
> Best
>
> Simon
>
>
> ------------------------------
> *De :* Castor-users <castor-users-bounces at lists.castor-project.org> de la
> part de Alessandro Pilleri <a.pilleri at gmail.com>
> *Envoyé :* mardi 15 décembre 2020 16:37
> *À :* castor-users at lists.castor-project.org
> *Objet :* [Castor-users] artifacts in the reconstruction
>
> Dear castor-users,
> I give an update to my previous email.
> I tried to change the min angle difference in the geometry file from 135
> (meaning a coincidence schema 1vs3) to 180 (meaning a coincidence schema
> 1vs1) and the two reconstructions provided exactly the same results.
>
> Could the artifact be related to some kind of bug (or a misuse by my side)
> related to the "min angle difference"?
>
> Thank you
> Alessandro
>
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