[Gate-users] need help: magnetic field makes no difference

[pkhateri]

Hi Jakub,

Sure! No problem.

That's true. Photons do not interact but positrons do. The effect should 
be observed on the positron range. Studies show that the magnetic filed 
can limit the range of positron movement in the direction perpendicular 
to the magnetic field. Therefore, we should see the scatter graph a bit 
squeezed along x and y axis in this example.

About my simulation, It was a sphere source located inside an acrylic 
cube (10mm each side). The source is defined as follows:
/gate/source/addSource                      point_source_O15_NEMA
/gate/source/point_source_O15_NEMA/setActivity       100000 becquerel
/gate/source/point_source_O15_NEMA/gps/type Volume
/gate/source/point_source_O15_NEMA/gps/shape         Sphere
/gate/source/point_source_O15_NEMA/gps/radius        0.5 mm
/gate/source/point_source_O15_NEMA/gps/particle      e+
/gate/source/point_source_O15_NEMA/gps/energytype    Oxygen15
/gate/source/point_source_O15_NEMA/useDefaultHalfLife
/gate/source/point_source_O15_NEMA/gps/centre        0 0 0 mm
/gate/source/point_source_O15_NEMA/gps/angtype       iso
/gate/source/point_source_O15_NEMA/setForcedUnstableFlag true
/gate/source/point_source_O15_NEMA/visualize 2000 blue 5
/gate/source/list


Please let me know if anything else should be clarified.

Bests,

Parisa
On 28.08.2019 15:21, jbaran wrote:
> Hi Parisa,
> 
> could you please be more specified regarding your simulations? I am so
> sorry if it is obvious to you and probably I missed something but
> photons wouldn't interact with the magnetic field as they don't have
> charge as i.e. electrons or positrons.
> 
> All the best,
> Jakub
> 
> 
> On 2019-08-28 15:11, pkhateri wrote:
>> Dear Gate users,
>> 
>> To check the effect of the magnetic field on my simulation result, I
>> added this command to my macro file:
>> /gate/geometry/setMagField 0.0 0.0 7.0 tesla
>> 
>> But I don't see any difference between the results with and without
>> the 7 tesla magnetic field. As an example, attached you can see a
>> scatter plot of the annihilation points for a point source (O-15)
>> located inside a 10^3mm^3 acrylic cube. The plots are identical.
>> 
>> Any idea what could be wrong with my simulation setting? I really 
>> appreciate it.
>> 
>> 
>> With kind regards,
>> 
>> Parisa
>> 
>> 
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