[Gate-users] Setting accolinearity with back to back source

[Albert Grace Lieu]

Hi Maxime,

Thanks for sharing your findings regarding this accolineraity feature
associated with the back-to-back gamma source. I did not see
"setAccolinearityFlag" command in the GATE 8 and 9 manual either and am
skeptical about its validity. May I know your conclusion on the usage of
accolineraity feature in GATE? Is it still supported or dead? How can one
still possibly use it correctly?

Thanks a lot.

Sincere wishes,

Zhengzhi

On Wed, Jul 1, 2020 at 11:39 AM Maxime Toussaint <
Maxime.Toussaint at usherbrooke.ca> wrote:

> Greetings,
>
> If one looks into the mailing list or in the Gate code, one can find that
> there is an option to simulate accolinearity from back to back source. The
> commands to use are as follow:
>     /gate/source/NAME/setAccolinearityFlag true
>     /gate/source/NAME/setAccoValue 0.5 deg
>
> In short, is this feature validated and still supported?
>
> In the following, I detail what I found from my search on that feature.
>
> This feature is not mentioned in the current openGate wiki (or at least,
> it was not found with the wiki search tool). I did a quick "cntrl+f" search
> of "setAccolinearityFlag" for the userguides available from v6.0 to the
> last available and I did not found a single mention of that keyword.
> However, if we look at the mailing list, we can find the following:
>
>    - A possible bug was found in 2011 for which the resulting thread does
>    not provide a clear conclusion about if the bug was corrected or if it was
>    a real bug [1].
>    - Around two years later, the feature was proposed to a user [4].
>    - This feature seems to be still used currently [2, 3]. In [3], the
>    user asked for some tips on the feature which were not answered.
>    - From Gate v5.0 to v6.0, a bug was found and corrected [5, 6, 7].
>
> I did try to look into the available release note of Gate and the Gate
> github but I did not find a mention about that feature.
>
> Currently, the option to test Gate with accolinearity validation does not
> work out-of-the-box with that feature. When I tried to activate the
> accollinearity error graph creation, the resulting graph indicated pure
> back-to-back events. I have built some tests by hand[*] and it showed that
> a Gaussian angular error was indeed simulated which is good. However, when
> I compared the accolinearity error resulting from that feature to when
> using a positron source[**], the profile were clearly different. The latter
> being Gaussian-like, as expected. It would seems that something unexpected
> happens when the angular error is applied to the gamma pairs momentum with
> that feature. While I did try to make sense of the code in the method
> "GenerateVertex" of GateBacktoBack.cc, I must admit I fail to comprehend
> all the steps it does.
>
> Thus, it seems that this feature might have some problems or that it is
> not completely supported. If it is indeed the case, I will propose a
> modification to the wiki such that it mention the existence of that feature
> but warns the users that it might not work as intended. If it should work,
> I will try to make a MWE of my tests and ask for validation.
>
> Best,
> Maxime Toussaint
>
>
> [1]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2011-February/004842.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2011-February%2F004842.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959885713&sdata=hErgjKVo%2BGaOLEjOHvH8hG1YyI5lN5dqKYuGGQwOx7A%3D&reserved=0>
> [2]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2020-June/011680.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2020-June%2F011680.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959895705&sdata=2r8SoyW0IZrf%2Btztjjbk9BW55g2tRu1cEOv56fwnhW4%3D&reserved=0>
> [3]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2019-December/011222.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2019-December%2F011222.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959895705&sdata=H%2BAvIhdArNubUAJJXV9l4Wzq18IozEXcLOu8jP%2FZweA%3D&reserved=0>
> [4]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2012-November/006068.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2012-November%2F006068.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959905700&sdata=%2B1j5zAFPGqBNayNUn1I6uf7joGaLYCdPOT5vbnRbuO0%3D&reserved=0>
> [5]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2010-November/004684.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2010-November%2F004684.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959905700&sdata=DAVufxRn3d%2BCb7VxOULE9siiR9FQ6pWBzo2nb%2FrYA3k%3D&reserved=0>
> [6]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2010-November/004683.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2010-November%2F004683.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959915693&sdata=wTA7OwcDUmICDa%2FOLyAgP%2FiRPIWTO%2FwIWt27j1GKcIY%3D&reserved=0>
> [7]
> http://lists.opengatecollaboration.org/pipermail/gate-users/2010-October/004599.html
> <https://can01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.opengatecollaboration.org%2Fpipermail%2Fgate-users%2F2010-October%2F004599.html&data=02%7C01%7CMaxime.Toussaint%40USherbrooke.ca%7C25315ca43ca74ed7ad0608d81de0a462%7C3a5a8744593545f99423b32c3a5de082%7C0%7C0%7C637292197959915693&sdata=F%2Fwogp5s9hJC1WtE2CujQWvG3GW%2BapOOIGMIJGiQnh8%3D&reserved=0>
>
> [*] Outputting the "dev" variable from the file GateBacktoBack.cc
> [**] Outputting the momentum from the file GateBacktoBack.cc and
> GatePositronAnnihilation.cc, and extracting the photon pairs accolinearity.
>
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