|Message: Why did my Method not Work||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)|
Hi, this is mostly a question of why my particular technique in finding area cross-sections and attenuation coefficients of materials in Geant4 did not work.
I currently understand that Extended Example 'TestEm13' is the main example provided by Geant4 to enable you to find the cross-section/attenuation coefficients of different materials, which was my original project, and now understand how to use that.
However, before i came across this example, i had come up with a particular method of finding the initial and transmitted gamma photon intensities through lead, by placing a slice of lead in a envelope, a particle gun on the edge of the envelope so that it shoots perpendicular to the slice of lead, and a box_mesh/scorer on the other side of the lead.
I set my own initial intensity of gamma photons, say 10,000, and the scorer/box_mesh which i implemented via commands, would 'count' or 'score the gammas that made it through the lead, onto the scorer/box_mesh.
The scorer would only count gamma photons making it on to the scorer via. 'FlatSurfaceCurrent' which is a method to count particles injecting the surface of the scorer without taking into account the angle at which the photon hits it.
I get good values in an external text file i created like, 9064/10,000 particles were counted, but when i start building up data of thickness of lead (which i change manually in between events and then re-build the application again) against the decreasing number of photons detected, i get an attenuation coefficient value that is not equal to the actual value I am meant to get.
What have i done wrong or understood wrong? - My envelope and world volumes are both as close to vacuum as you can get. - My detector is the Geant4 default lead material of varying thickness. - My scorer is a simple box mesh, divided into 50 by 50 bins i.e. (50,50,0).
I really wish to understand how to use Geant4 to a really good level, so I would appreciate any and all feedback on this, thank you for helping.
|Inline Depth:||Outline Depth:||Add message:|