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<div class="moz-cite-prefix">Maybe others can correct me if I am
wrong - but the source defines just the distribution of the
primary particles (for the ParticleGun object of Geant4), and has
no relation whatsoever on the material in the vicinity of the
source. Once the primary particle is created, transportation
algorithms propagate its path through the volume, occupied by
entities defined in geometry part of the simulation setup. Hence -
if you world volume is made of vacuum, and no other volumes were
added, the source is in vacuum as well.<br>
<br>
If you want your source to be of particular material, you have to
crate a daughter volume of the world volume (see gate manual for
exact syntax) of an appropriate size and material. Then tracking
will use that particular material and do Compton/Rayleigh
accordingly.<br>
<br>
If you want annulus source, you also have to think about material
of the prohibited volume. I can't really say it should be a
particular type since I have no idea what you want to simulate. <br>
<br>
Hope this helps<br>
<br>
Andrej<br>
<br>
On 01/08/16 10:06, Pawe Kowalski wrote:<br>
</div>
<blockquote
cite="mid:995779472.1598777.1452243975731.JavaMail.yahoo@mail.yahoo.com"
type="cite">
<div style="color:#000; background-color:#fff;
font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial,
Lucida Grande, sans-serif;font-size:16px">
<div id="yui_3_16_0_1_1452236762616_4985">Hi,</div>
<div id="yui_3_16_0_1_1452236762616_4951"><br>
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4950">In my
simulations I have volume source of back-to-back gamma
quanta. </div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4986">I would like
to ask if this is possible to have some Compton or Rayleigh
scatterings in this source? </div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949">If space
around source is a vacuum, then source is also treated as a
vacuum? Going forward, if space around source is an air, then
source is also treated as an air?</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949"><br>
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949">My
definition of source:</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949"><br>
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">#=====================================================</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">#
linear source</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">#=====================================================</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class=""><br
id="yui_3_16_0_1_1452236762616_5074" class="">
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/addSource
linear gps</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class=""><br
id="yui_3_16_0_1_1452236762616_5078" class="">
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/type
Volume</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/shape
Cylinder</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/radius
3.2 mm</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/halfz
35. cm</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/pos/centre
0. -45. 0. mm</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class=""><br
id="yui_3_16_0_1_1452236762616_5086" class="">
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/setActivity
5000000 Bq</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/setType
backtoback</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/particle
gamma</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/ene/mono
511. keV</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/linear/gps/angtype
iso</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class=""><br
id="yui_3_16_0_1_1452236762616_5094" class="">
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949" class="">/gate/source/list</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949"><br>
</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949">Best
regards,</div>
<div dir="ltr" id="yui_3_16_0_1_1452236762616_4949">Paweł
Kowalski</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
****************************************
dr. Andrej Studen
Jozef Stefan Institute,
Jamova 39, 1000 Ljubljana, Slovenia
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