Message: Problem with muons hit position inside the sensitive volume Not Logged In (login)
 Next-in-Thread Next-in-Thread
 Next-in-Forum Next-in-Forum

None Problem with muons hit position inside the sensitive volume 

Forum: Event and Track Management
Date: 06 Dec, 2017
From: Hector Gomez <Hector Gomez>

I want to perform a simulation detecting muons in a gas volume. The goal is to register all the energy deposits to be able to reconstruct the muon track.

As first simple example I define a gas box volume (x = y = 50 cm; z = 1 cm centred at x = y = 0 cm) and I throw negative muons of fixed energy (12 GeV) and direction (0,0,1), i.e. perpendicular to the gas-box x-y surface.

When I register the output, the energy deposit as well as the x and y position of the hits seem to be correct. This is not the case for the z coordinate. A clear excess of hits appears at the end of the gas-box volume  in the z-coordinate (see attached plot together with the x and y distributions of the hits, which seem normal)

The way I store the hit position (x,y,z) is the following:

 G4ThreeVector hitpos = aStep->GetPostStepPoint()->GetPosition();

Among the different tests I performed, I observed the same effect:

- Changing the gas volume thickness (z) up to 100 cm

- Changing the material of my sensitive box (using the G4_POLYSTYRENE  material)

- Using a muon energy distribution and not mono-energetic ones as well as changing the generation point

- Using different physics lists (the Geant4 standard and theG4EmLivermorePhysics for example)

Anybody knows what could be the origin of this behaviour and the way to solve it?

Thank you very much in advance!

   Attachment:
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/12/06/07.59-95942-HitXPos.png
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/12/06/07.59-4086-HitYPos.png
      http://hypernews.slac.stanford.edu/HyperNews/geant4/get/AUX/2017/12/06/07.59-42587-HitZPos.png

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

1 Feedback: Re: Problem with muons hit position inside the sensitive volume   (Gumplinger Peter - 06 Dec, 2017)
2 Feedback: Re: Problem with muons hit position inside the sensitive volume   (Michael H. Kelsey - 06 Dec, 2017)
1 More: Re: Problem with muons hit position inside the sensitive volume   (Hector Gomez - 07 Dec, 2017)
(_ None: Re: Problem with muons hit position inside the sensitive volume   (michel maire - 07 Dec, 2017)
 Add Message Add Message
to: "Problem with muons hit position inside the sensitive volume"

 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 ]