<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <meta name="Generator" content="Microsoft Exchange Server">  <style></style> </head> <body> <font face="Calibri, sans-serif" size="2"> <div>Hello Gaters,</div> <div> </div> <div>I am trying to define a x-ray source using the user-defined energy histogram. My question is how do I define the unit when using /histpoint to define the energy histogram? And if I want to define two histograms – for example one for energy and one for angle, how does Gate know which histogram each /histpoint belong to. </div> <div>Below is the macro file I have: Could any one check for me if I am right? Thanks a lot.</div> <div><font face="Times New Roman, serif"> </font></div> <div>/gate/source/addSource xraygun</div> <div>/gate/source/xraygun/setActivity   3.5 becquerel</div> <div>/gate/source/xraygun/gps/particle gamma</div> <div>/gate/source/xraygun/gps/energytype User</div> <div><font color="#FF0000">/gate/source/xraygun/gps/histname energy</font></div> <div><font color="#FF0000">/gate/source/xraygun/gps/histpoint 0.32 0.5</font></div> <div><font color="#FF0000">/gate/source/xraygun/gps/histpoint 0.64 0.5</font></div> <div><font face="Times New Roman, serif"> </font></div> <div>/gate/source/xraygun/gps/type Plane</div> <div>/gate/source/xraygun/gps/shape Rectangle</div> <div>/gate/source/xraygun/gps/halfx 1.5 cm</div> <div>/gate/source/xraygun/gps/halfy 1.5 cm</div> <div>/gate/source/xraygun/gps/centre 0. 0. -1.6 cm</div> <div> </div> <div>/gate/source/xraygun/gps/angtype iso</div> <div>/gate/source/xraygun/gps/mintheta 0. deg</div> <div>/gate/source/xraygun/gps/maxtheta 0. deg</div> <div> </div> <div><font face="Times New Roman, serif"> </font></div> <div>Regards,</div> <div> </div> <div>Ming Yang, M.S.</div> <div>Graduate Research Assistant</div> <div>Radiation Physics Department</div> <div>MD Anderson Cancer Center</div> <div>Office #: B2.4510</div> <div>Office Phone #: 713-745-0464</div> <div> </div> <div><font face="Times New Roman, serif"> </font></div> <div><font face="Times New Roman, serif"> </font></div> </font> </body> </html>