<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> </head> <body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"> <div><br> </div> Hi Mattia, <div><br> </div> <div>there is nothing wrong, that you find much less coincidences than just half</div> <div>the singles. Consider the requirement for true coincidences: </div> <div>- the singles have to come from the same event, </div> <div>- scattered photons might miss the threshold you have set</div> <div>- there is absorption in the phantom and you lose one of the annihilation photons</div> <div><br> </div> <div>Maybe it would be a good exercise if you use the PET benchmark</div> <div>or have a look at the very simple EduGATE- examples you find on the GATE WEB-page,</div> <div>like "Coin-Chan"</div> <div><br> </div> <div>Hope this helps!</div> <div><br> </div> <div>Kind regards and best wishes,</div> <div><br> </div> <div>Uwe Pietrzyk</div> <div> <div> <div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"> <div><span style="orphans: 2; widows: 2;">/----------------------------------------------------------------------</span></div> <div style="orphans: 2; widows: 2;">Prof. Dr. Uwe Pietrzyk<br> Diplom-Physiker<br> Institut für Neurowissenschaften und Medizin / INM-4<br> Forschungszentrum Jülich GmbH<br> 52425 Jülich<br> Tel: +49-2461-61 4763<br> Fax: +49-2461-61 2820<br> Mobil: +49-162-103-4871<br> eMail: <a href="mailto:U.Pietrzyk@fz-juelich.de">U.Pietrzyk@fz-juelich.de</a><br> <a href="http://www.fz-juelich.de/inm/inm-4/DE/Home/home_node.html">http://www.fz-juelich.de/inm/inm-4/DE/Home/home_node.html</a><br> &<br> Bergische Universität Wuppertal<br> Fakultät für Mathematik und Naturwissenschaften</div> <div style="orphans: 2; widows: 2;">Büro: D.08.01<br> Gaußstr. 20<br> 42097 Wuppertal<br> Tel: +49-(0)202-439-3523<br> Fax: +49-(0)202-439-2811<br> eMail: <a href="mailto:Uwe.Pietrzyk@physik.uni-wuppertal.de">Uwe.Pietrzyk@uni-wuppertal.de</a><br> <a href="http://www.medizinphysik.uni-wuppertal.de/">http://www.medizinphysik.uni-wuppertal.de</a><br> ----------------------------------------------------------------------/</div> </div> </div> <br> <div> <div>On 22 Jun 2016, at 18:16, mattia cani <<a href="mailto:mattiacani@hotmail.it">mattiacani@hotmail.it</a>> wrote:</div> <br class="Apple-interchange-newline"> <blockquote type="cite"><style type="text/css" style="display:none;"></style> <div dir="ltr"> <div id="divtagdefaultwrapper" style="font-size: 12pt; background-color: rgb(255, 255, 255); font-family: Calibri, Arial, Helvetica, sans-serif;"> <p>Hi everybody,</p> <p>I am using Gate for my thesis project and now I am doing some simulations with a Derenzo phantom. I have a question about the expected number of coincidences. I am doing some short simulations just to understand how it works so I have 1s of time with 28 different sources of 5000 Bq each one. At the end of the simulation on the ROOT output I can see that we have about 22000 singles but just 1468 concidences, while I expected about 11000. Maybe the problem is the digitizer setting so I enclose that part of the code. </p> <p><br> </p> <div><br class="webkit-block-placeholder"> </div> <div># A D D E R<br> /gate/digitizer/Singles/insert adder<br> <br> <br> # R E A D O U T <br> /gate/digitizer/Singles/insert readout<br> /gate/digitizer/Singles/readout/setDepth 1<br> <br> <br> # E N E R G Y B L U R R I N G<br> /gate/digitizer/Singles/insert blurring<br> /gate/digitizer/Singles/blurring/setResolution 0.26<br> /gate/digitizer/Singles/blurring/setEnergyOfReference 511. keV<br> <br> <br> # E N E R G Y C U T<br> /gate/digitizer/Singles/insert thresholder<br> /gate/digitizer/Singles/thresholder/setThreshold 250. keV<br> /gate/digitizer/Singles/insert upholder<br> /gate/digitizer/Singles/upholder/setUphold 750. keV<br> <br> <br> # D E A D T I M E <br> /gate/digitizer/Singles/insert deadtime<br> /gate/digitizer/Singles/deadtime/setDeadTime 2.2 mus<br> /gate/digitizer/Singles/deadtime/setMode paralysable<br> /gate/digitizer/Singles/deadtime/chooseDTVolume block<br> <br> <br> # C O I N C I S O R T E R <br> /gate/digitizer/Coincidences/setWindow 24. ns<br> /gate/digitizer/Coincidences/MultiplesPolicy takeAllGoods<br> /gate/digitizer/Coincidences/setOffset 0. ns<br> /gate/digitizer/Coincidences/describe<br> <br> /gate/digitizer/name delay<br> /gate/digitizer/insert coincidenceSorter<br> /gate/digitizer/delay/setWindow 24. ns<br> /gate/digitizer/delay/setOffset 500. ns<br> /gate/digitizer/delay/describe<br> <br> <br> /gate/digitizer/name finalCoinc<br> /gate/digitizer/insert coincidenceChain<br> /gate/digitizer/finalCoinc/addInputName delay<br> /gate/digitizer/finalCoinc/addInputName Coincidences<br> /gate/digitizer/finalCoinc/usePriority true<br> /gate/digitizer/finalCoinc/describe<br> </div> <div><br class="webkit-block-placeholder"> </div> <p><br> </p> <p><br> </p> <p>Thank you for your disposability</p> <p>Best regards</p> <p>Mattia<br> </p> </div> </div> _______________________________________________<br> Gate-users mailing list<br> <a href="mailto:Gate-users@lists.opengatecollaboration.org">Gate-users@lists.opengatecollaboration.org</a><br> http://lists.opengatecollaboration.org/mailman/listinfo/gate-users</blockquote> </div> <br> </div> <br> <font face="Arial" color="Black" size="1"><br> ------------------------------------------------------------------------------------------------<br> ------------------------------------------------------------------------------------------------<br> Forschungszentrum Juelich GmbH<br> 52425 Juelich<br> Sitz der Gesellschaft: Juelich<br> Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. 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