<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body><div style="font-family:Helvetica,Arial;font-size:13px; "><div style="margin: 0px;">Good evening,</div><div style="margin: 0px;"><span class="Apple-tab-span" style="white-space:pre"> </span>To test the generation of Cherenkov photons on Gate, I ran on my macOSX computer a test code, where I commented the scintillation process, I kept the Cherenkov process, and I shoot 511 keV in a PbWO4 crystal.</div><div style="margin: 0px;"><br></div><div style="margin: 0px;"><span class="Apple-tab-span" style="white-space:pre"> </span>I attach you the output file, for such a macro, executed </div><div style="margin: 0px;"><span class="Apple-tab-span" style="white-space:pre"> </span>- on my computer running Gate-Dev under Geant4-V10.7.p1 and </div><div style="margin: 0px;"><span class="Apple-tab-span" style="white-space:pre"> </span>- on an unix computer running Gate_V9.0. under Geant4-V10.6</div><div style="margin: 0px;"><br></div><div style="margin: 0px;">In both cases you will notice that even during a photoelectric conversion in the crystal, (511keV deposited) no optical photon is generated, so no Cherenkov photon. We would expect on average 20 Cherenkov optical photons</div><div style="margin: 0px;"><br></div><div style="margin: 0px;">If on the other hand, when I restore the scintillation process, (TestScinGateDevMacOS.txt) a large number of optical photons are produced.</div><div style="margin: 0px;"><br></div><div style="margin: 0px;">I conclude that the Cherenkov process is broken in both installs.</div><div style="margin: 0px;">What do you think?</div><div style="margin: 0px;"><br></div><div style="margin: 0px;"><span class="Apple-tab-span" style="white-space:pre"> </span>Best regards</div></div><br><div class="gmail_signature"><font face="Helvetica"><span style="font-size: 12px;">Dr. Dominique Yvon, HDR</span></font><div><font face="Helvetica"><span style="font-size: 12px;">CEA Saclay - IRFU/DPHP, Bat 141, PC21, F-91191 Gif sur Yvette Cedex</span></font></div><div><font face="Helvetica"><span style="font-size: 12px;">BioMaps, SHFJ, 4 place du général Leclerc, 91401 Orsay France</span></font></div><div><font face="Helvetica"><span style="font-size: 12px;">Tél: 01 6908 3625</span></font></div><div><font face="Helvetica"><span style="font-size: 12px;">Email: dominique.yvon@cea.fr</span></font></div></div></body></html>