[Gate-users] Positron range simulation - inconsistency between GATE 8.0/ 9.0 and between source types

[Minh Phuong Nguyen]

Can anyone help me with this?
The inconsistency in the positron range simulation with GATE appears to be
an existing problem.
Several related posts in the gate-user archive have not received a final
answer either.

Minh

On Thu, Nov 5, 2020 at 10:29 AM Minh Phuong Nguyen <mipbkhn at gmail.com>
wrote:

> Dear GATErs,
>
> I simulated positron ranges for several isotopes such as F-18 and I-124
> with GATE. The setup was very simple with a point source at the centre of a
> water environment (20-cm-radius sphere). The sphere was that large to make
> sure that the positrons do not escape the water volume.
>
> The obtained mean/max positron range from this simulation was shorter than
> what I found in literature. Then I tested with different GATE versions
> (8.0/ 9.0 with corresponding GEANT4 versions as stated in the GATE
> documentation), and different ways of defining the source (ion, e+,
> fastI124). I observed that the positron range result was not consistent
> when changing these parameters (attached figures).
>
> Looking at the range distributions (attached figures), GATE 8.0 with ion
> source produced a lot of annihilations near the decay locations (range ~ 0
> mm). This was not the case with GATE 9.0 and e+ or fastI124 sources.
>
> Does anybody know:
> - why positron range from GATE is shorter than in literature?
> - which changes in the new GATE version makes the discrepancy in positron
> range simulation result?
> - what makes the difference in positron range between the ion source and
> other type sources?
>
> Thank you.
> Kind regards,
> Minh Phuong Nguyen
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opengatecollaboration.org/pipermail/gate-users/attachments/20201109/9a0f483a/attachment.html>