|Message: Re: Why is change in KineE not equal to dEStep?||Not Logged In (login)|
Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.
Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.
Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.
|1||0||1||no text / full text of posting|
|2||1||All||text for level 1 only / text for All postings|
Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.
|1||2||1||2 levels / 1 level (original posting)|
|2||3||2||3 levels / 2 levels|
|3||3||All||3 levels / all levels (all postings)|
On Tue, 06 Sep 2011 13:50:56 GMT, michel maire wrote:
> On Mon, 05 Sep 2011 15:23:18 GMT, Neil Fazel wrote: > > > I'm using verbose tracking to print out the kinetic energy (KineE) and > > total energy deposited (dEStep) at each step on a track. I see that > > dEStep does not equal the change in KineE. For example, below you see > > that for Step# 3, KineE has decreased to 159 MeV from 999 MeV, but > > dEStep is only 4.73 keV. What happened to kinetic energy difference (840 > > MeV) and what does dEStep = 4.73 keV represent? > > > > (This is for a 1 GeV e- passing through a 1 cm layer of Pb.) > > > > if you run with tracking/verbose 2, you will understand your ouput (I hope ...). > For the second part of the question, please read a minimum of documentation about geant4, or any MC transport code in general ... > > Michel >
Thanks. What I understand from the verbose tracking output is that changes in the kinetic energy of the electron in lead are the sum of the energy imparted to secondary particles (gamma or delta rays) plus the value of dEStep, which is apparently the energy deposited in the detector. According to the Physics Ref. Manual, ch. 7.1,
"Any energy loss process must calculate the continuous and discrete energy loss in a material. Below a given energy threshold the energy loss is continuous and above it the energy loss is simulated by the explicit production of secondary particles - gammas, electrons, and positrons."
It occurred to me that dEStep represented the continuous energy loss, but then the paragraph above suggests that either the continuous (below cutoff) or the discrete (above cutoff) energy loss occurs during a given step, not both. It looks like I have both.