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

Wed Jul 1 20:38:47 CEST 2020

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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