GSI Forum: EMC » Uniform particle generation in solid angle

Home » PANDA » PandaRoot » EMC » Uniform particle generation in solid angle

Show: Today's Messages :: Polls :: Message Navigator

Uniform particle generation in solid angle [message #11678]

Mon, 18 April 2011 09:07

HosseinMoeini
Messages: 10
Registered: May 2007
Location: KVI Groningen

occasional visitor

From: *KVI.nl

Dear all,

I was wondering if there's an easy way to generate particles along a unit 3-vector. As I noticed, the box generator in emc_complete.c doesn't do this. Apparently, it draws a random number within the specified ranges of theta and phi. What I need is something like G4RandomDirection function. I hit the problem when I roughly calculated the solid angle coverage of the full EMC to be about 92%. Whereas, the efficiency calculation using the box generator gives me something around 85% which indicates a bigger probability for particle generation at the poles (entrance and exit holes of the EMC)! Am I missing something here or there is other alternative to the box generator?

Best regards

Report message to a moderator

Re: Uniform particle generation in solid angle [message #11680 is a reply to message #11678]

Mon, 18 April 2011 11:53

Dima Melnychuk
Messages: 213
Registered: April 2004
Location: National Centre for Nucle...

first-grade participant

From: *fuw.edu.pl

Hi Hossein,

I suppose you should use the option
boxGen->SetCosTheta();
in box generator to have particles uniformly distributed in solid angle.

See the following post for details:

http://forum.gsi.de/index.php?t=tree&th=1318&start=0&rid=78& amp;S=2fcdba1e0ae8f392cb61ca826979c23a#page_top

Dima

Report message to a moderator