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<TITLE>RE: [Gate-users] Z position</TITLE>
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<P><FONT SIZE=2>The peak in bottom is due to your geometry setting: the sensitive detector is the same as<BR>
world size at -z, then no photons can escape your SD. You need to set your world size in z<BR>
slightly bigger.<BR>
<BR>
None of your three plots makes sense to me. Maybe next time you can look only those with<BR>
small globalPosX, Y events.<BR>
<BR>
Yu Chen, Ph.D.<BR>
University of Massachusetts Medical School<BR>
Division of Nuclear Medicine<BR>
55 Lake Avenue North<BR>
Worcester, MA 01655-0243<BR>
Phone: (508) 856-6123<BR>
Fax: (508) 856-4572<BR>
<BR>
<BR>
<BR>
-----Original Message-----<BR>
From: gate-users-bounces@lists.healthgrid.org on behalf of venialgo_e<BR>
Sent: Thu 2/14/2008 8:16 AM<BR>
To: gate-users@lists.healthgrid.org<BR>
Subject: [Gate-users] Z position<BR>
<BR>
Hello Gate users,<BR>
<BR>
I'm studying the effect of Depth Of Interaction in a crystal of NaI. I <BR>
simulated a detector of 30cm x 40 cm x 2.5 cm using a source with <BR>
several emission angles.<BR>
<BR>
the detector is:<BR>
<BR>
/gate/scanner/daughters/name cristalIoduro<BR>
/gate/scanner/daughters/insert box<BR>
/gate/cristalIoduro/geometry/setXLength 5 cm<BR>
/gate/cristalIoduro/geometry/setYLength 5 cm<BR>
/gate/cristalIoduro/geometry/setZLength 2.5 cm<BR>
/gate/cristalIoduro/placement/setTranslation 0 0 -1.25 cm<BR>
/gate/cristalIoduro/setMaterial NaI<BR>
/gate/cristalIoduro/vis/setColor red<BR>
/gate/cristalIoduro/attachCrystalSD<BR>
<BR>
<BR>
the source is:<BR>
<BR>
/gate/source/addSource cesio<BR>
/gate/source/cesio/setActivity 20000 becquerel<BR>
/gate/source/cesio/gps/centre 0. 0. 1 cm<BR>
/gate/source/cesio/gps/particle gamma<BR>
/gate/source/cesio/gps/energytype Mono<BR>
/gate/source/cesio/gps/monoenergy 0.622 MeV<BR>
/gate/source/cesio/gps/type Volume<BR>
/gate/source/cesio/gps/shape Sphere<BR>
/gate/source/cesio/gps/radius 0 cm<BR>
/gate/source/cesio/gps/angtype iso<BR>
<BR>
<BR>
1)In the first case the emission angle is:<BR>
/gate/source/cesio/gps/mintheta 0. deg<BR>
/gate/source/cesio/gps/maxtheta 0. deg<BR>
/gate/source/cesio/gps/minphi 0. deg<BR>
/gate/source/cesio/gps/maxphi 360. deg<BR>
<BR>
2)In the second, it is:<BR>
/gate/source/cesio/gps/mintheta 0. deg<BR>
/gate/source/cesio/gps/maxtheta 3. deg<BR>
/gate/source/cesio/gps/minphi 0. deg<BR>
/gate/source/cesio/gps/maxphi 360. deg<BR>
<BR>
3)In the last, it is:<BR>
/gate/source/cesio/gps/mintheta 0. deg<BR>
/gate/source/cesio/gps/maxtheta 20. deg<BR>
/gate/source/cesio/gps/minphi 0. deg<BR>
/gate/source/cesio/gps/maxphi 360. deg<BR>
<BR>
<BR>
And The questions about Z positions of the singles are:<BR>
<BR>
<BR>
1)In the first case , why are there a lot of counts only on the <BR>
crystal's top face?.<BR>
<BR>
2)In the second case, why are there more counts in one half of the <BR>
crystal than the other?<BR>
<BR>
3)In the third case. why is there a peak of counts, in the crystal's <BR>
bottom face ?.<BR>
<BR>
<BR>
P.D.: I attached the macro files for each case, and gif files with the <BR>
Z position's histograms of the singles, also.<BR>
<BR>
Thanks in advance,<BR>
<BR>
Esteban Venialgo<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
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