Message: Re: GPS negative z-direction Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None Re: GPS negative z-direction 

Forum: Particles
Re: Question GPS negative z-direction (matthew)
Date: 23 Nov, 2011
From: Fan Lei <Fan Lei>

On Thu, 29 Sep 2011 00:51:24 GMT, matthew wrote:
> I am trying to transport a 2-D beam of thermal neutrons through my geometry, but for some reason all the neutrons move away from my detector instead of toward it.
> 
> The code is as follows:
> /gps/verbose 0
> /gps/particle neutron
> /gps/direction 0 0 1
> #
> # the incident surface is in the y-z plane
> /gps/pos/type Beam
> /gps/pos/shape Circle
> /gps/pos/radius 2.54 cm
> /gps/pos/centre 0.0 0.0 0.0 m
> #
> # set the focusing point, default is (0, 0, 0)
> /gps/ang/type beam2d
> # Set the energy distribution
> /gps/energy 0.025 eV
> 
> I thought I could just change the third line of code to
> 
> /gps/direction 0 0 -1
> 
> but that did not fix the problem.  I'm obviously misunderstanding something.  What am I doing wrong?
> 
The command "/gps/ang/type beam2d" overwrites "/gps/direction" and redefines the angular distribution. To change the direction of the beam, you have to use the commands "/gps/ang/rot1" and "/gps/ang/rot2". The GPS users manual provides you more details:

http://reat.space.qinetiq.com/gps/new_gps_sum_files/Document.htm#ga

Fan

Inline Depth:
 1 1
 All All
Outline Depth:
 1 1
 2 2
 All All
Add message: (add)

1 Idea: Re: GPS negative z-direction   (Ivan Sivacek - 23 Nov, 2011)
 Add Message Add Message
to: "Re: GPS negative z-direction"

 Subscribe Subscribe

This site runs SLAC HyperNews version 1.11-slac-98, derived from the original HyperNews


[ Geant 4 Home | Geant 4 HyperNews | Search | Request New Forum | Feedback ]