<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> <META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7651.59"> <TITLE>RE: [Gate-users] Z position</TITLE> </HEAD> <BODY>  When there are nothing on root file for 1000 events, it must be something wrong. I commented out /gate/world/daughters/insert 3axes then it runs without problem. Generated 1000 bg* 100s = 10^4 events, obtained ~5x10^3 singles in 2.5 cm NaI. You can estimate to see if it is correct using known attenuation coefficient. Among them are there half with energy > 600 keV but still occured Compton scattering. Those without Compton scatter (6426) lie a perfect exponential distribution (see attached pdf).  Yu Chen, Ph.D. University of Massachusetts Medical School Division of Nuclear Medicine 55 Lake Avenue North Worcester, MA 01655-0243 Phone:  (508) 856-6123 Fax:    (508) 856-4572 -----Original Message----- From: venialgo_e [<A HREF="mailto:venialgo_e@secyt.frba.utn.edu.ar">mailto:venialgo_e@secyt.frba.utn.edu.ar</A>] Sent: Wed 2/20/2008 8:47 AM To: Chen, Yu Subject: RE: [Gate-users] Z position I attached the file 1000bq.root and 1000bq.mac .For 1000 bq  and 1  second there aren't counts in the detector.     bye,     Esteban Venialgo "Chen, Yu" <Yu.Chen@umassmed.edu> ha escrito: > I strongly suspect you were plotting "hit" not "singles". > > The following is my message last time to you: > >> Are you sure you plotted *Singles*? >> From you macro, we can't see any digitizing module used. > >> You generated 20000*3 photons but have more than 60000 entries. >> It may explain some if what you actually plotted is hit (step)   >> point position. > > > Put > /gate/output/root/setRootSinglesFlag 1 > in your mac > and no energy window needed > > Run 1000 bq and 1 sec > send your root file to me. > > Yu Chen, Ph.D. > University of Massachusetts Medical School > Division of Nuclear Medicine > 55 Lake Avenue North > Worcester, MA 01655-0243 > Phone:  (508) 856-6123 > Fax:    (508) 856-4572 > > > > -----Original Message----- > From: gate-users-bounces@lists.healthgrid.org on behalf of venialgo_e > Sent: Mon 2/18/2008 12:34 PM > To: Chen, Yu; gate-users@lists.healthgrid.org > Subject: RE: [Gate-users] Z position > > Yes, I don't have any digitalizer modules, because I have done Matlab > scripts in the way to have more freedom to select scatter and > photoelectric interactions or both, calculate position using weighted > average for position, and apply energy windows, etc. > > Anyway I connect an adder and a energy window to system and... > > In case 1 there are two peaks of counts in the crystal's top face, if > the digitalizer is only an adder. The name of the files are > case1_wo_window.gif and case1_wo_window.mac    .But if the digitalizer > has an adder and energy window, so there is a maximum of counts in 18 > mm approx.   .The files for that case are case1digitalizer.gif and > case1digitalizer.mac. > > For case 2, is the same than before. There are counts only in second > half of the crystal with an adder and energy window. The files are > case2digitalizer.gif and case2digitalizer.mac. > > And, In case 3, There is a maximum of counts in 10 mm approx, with and > adder and energy window. The files are case3digitalizer.gif and > case3digitalizer.mac . > > > > I can't understand the different shapes of Z position. I expected and > exponential decreasing shape. > > > >       Thanks a lot for your support. >       Esteban Venialgo. > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program. > > ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program. </BODY> </HTML>