<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div dir="ltr" data-setdir="false">Dear GATE users,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false"> <div><div>I tried to simulate the I-123 photons spectrum (a) using only 159 keV photon (83.3%) in one simulation and (b) all other high energy photons greater than 159 keV (~3%) in another simulation. </div><div><br></div><div>In both of my simulations, I simulated a fixed number of primaries (decays) so that I could estimate the contribution of 159 keV and high energy photons separately. However, by defining the sources (see below), a similar number of photons have been detected in both simulations! This is undesirable as the intensity of their emissions are hugely different, as defined in the lines below. It looks like GATE normalized the intensity value (probability of emission); as a result of that, I may end up getting similar results for both simulations. Now, my question is, how can I define the sources in (b) to get a proportionate number of photons detection? If my assumption is right about normalization, is it possible to force GATE not to normalize the intensity values in (b)?</div></div><br></div><div dir="ltr" data-setdir="false"><span><span style="color: rgb(0, 0, 0); font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; font-size: 16px;"><br></span></span></div><div dir="ltr" data-setdir="false"><b>For (a) I define the following lines of code in my simulation settings:</b><br></div><div dir="ltr" data-setdir="false">/gate/source/addSource src1 gps<br></div><div dir="ltr" data-setdir="false"><div><div>/gate/source/src1/gps/particle gamma</div><div>/gate/source/src1/gps/energytype Mono</div><div>/gate/source/src1/gps/ene/mono 158.97 keV<br></div><div>/gate/source/src1/setIntensity 0.833</div><div>/gate/source/src1/gps/angtype iso</div><div>/gate/source/src1/gps/type Point</div><div>/gate/source/src1/gps/centre 0. 0. 0. mm</div><div>/gate/source/src1/attachTo src_1</div><div>/gate/source/list<br></div><div><br></div></div><b>For (b) I selected 5 major gamma emissions having energy greater than 159 keV:</b></div><div dir="ltr" data-setdir="false"><div><div>/gate/source/addSource src1 gps</div><div>/gate/source/src1/gps/particle gamma</div><div>/gate/source/src1/gps/energytype Mono</div><div>/gate/source/src1/gps/ene/mono 346.35 keV<br></div><div>/gate/source/src1/setIntensity 0.00125783</div><div>/gate/source/src1/gps/angtype iso</div><div>/gate/source/src1/gps/type Point</div><div>/gate/source/src1/gps/centre 0. 0. 0. mm</div><div>/gate/source/src1/attachTo src_1</div><div><br></div><div>/gate/source/addSource src2 gps</div><div>/gate/source/src2/gps/particle gamma</div><div>/gate/source/src2/gps/energytype Mono</div><div>/gate/source/src2/gps/ene/mono 440.02 keV<br></div><div>/gate/source/src2/setIntensity 0.00428162</div><div>/gate/source/src2/gps/angtype iso</div><div>/gate/source/src2/gps/type Point</div><div>/gate/source/src2/gps/centre 0. 0. 0. mm</div><div>/gate/source/src2/attachTo src_1</div><div><br></div><div>/gate/source/addSource src3 gps</div><div>/gate/source/src3/gps/particle gamma</div><div>/gate/source/src3/gps/energytype Mono</div><div>/gate/source/src3/gps/ene/mono 505.33 keV<br></div><div>/gate/source/src3/setIntensity 0.00315707</div><div>/gate/source/src3/gps/angtype iso</div><div>/gate/source/src3/gps/type Point</div><div>/gate/source/src3/gps/centre 0. 0. 0. mm</div><div>/gate/source/src3/attachTo src_1</div><div><br></div><div>/gate/source/addSource src4 gps</div><div>/gate/source/src4/gps/particle gamma</div><div>/gate/source/src4/gps/energytype Mono</div><div>/gate/source/src4/gps/ene/mono 528.96 keV<br></div><div>/gate/source/src4/setIntensity 0.013911</div><div>/gate/source/src4/gps/angtype iso</div><div>/gate/source/src4/gps/type Point</div><div>/gate/source/src4/gps/centre 0. 0. 0. mm</div><div>/gate/source/src4/attachTo src_1</div><div><br></div><div>/gate/source/addSource src5 gps</div><div>/gate/source/src5/gps/particle gamma</div><div>/gate/source/src5/gps/energytype Mono</div><div>/gate/source/src5/gps/ene/mono 538.54 keV<br></div><div>/gate/source/src5/setIntensity 0.00381514</div><div>/gate/source/src5/gps/angtype iso</div><div>/gate/source/src5/gps/type Point</div><div>/gate/source/src5/gps/centre 0. 0. 0. mm</div><div>/gate/source/src5/attachTo src_1</div></div><br></div><div dir="ltr" data-setdir="false">Any help is highly appreciated. Thanks in advance.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Regards,</div><div dir="ltr" data-setdir="false">Ashok </div></div></body></html>