[gate-users] Re: How to input a history file

[Chen, Yu]

Hi,

Thank Mikhail, David, Ross for bringing up this brilliant idea.

We have also considered how to implement such method into GATE. 

As mentioned by David, it is relevantly simple to generate a particle
in Geant4 (or GATE). The GeneratePrimaryVertex only needs to know 
three kinds of information: particle name, position, momentum.

If we have an input source file like:

Particle  PosX PosY PosZ px py pz
---------------------------------
gamma      x    x     x   x  x  x

we can read it in and use GeneratePrimaryVertex or even use GPS 
which GATE already implemented:

.../gps/particle gamma
.../gps/position Posx PosY PosZ
.../gps/direction px py pz
.../gps/energy sqrt(px*px+py*py+pz*pz)


But, how can we get such gamma distribution file from GATE, say, in the boundary 
of defined phantom?

Looking at the GATE User's Guide, it seems that we can have three types of output:
hits, singles, coincidences. Obviously none of them satisfies our input gamma distribution
requirements since hits are steps in materials (same particle can have many hits) and single
is simply the collection of hits.  

Mikhail, have you gotten any "history file" from GATE? and what does it look like?

In summary, to accomplish the new function in GATE

GATE gamma distribution output in phantom boundary --> input to GATE (random1)
                                                   --> input to GATE (random2) 
                                                   -->   ...

I think we need to:

1) define an output/input format;
2) implement a method to output gamma distribution in phantom boundary;
3) implement a method to input such a file to generate, like what Mikhail wanted. 

What do I miss?

Best, Yu


Yu Chen, Ph.D.
University of Massachusetts Medical School
Division of Nuclear Medicine
55 Lake Avenue North
Worcester, MA 01655-0243
Phone:  (508) 856-6123
Fax:    (508) 856-4572



-----Original Message-----
From: David Guez [mailto:dguez at cea.fr]
Sent: Tue 8/2/2005 4:21 AM
To: GATE feedback and helpline for Users
Subject: Re: [gate-users] Re: How to input a history file
 
GUEZ David wrote:

> Hi,
> the class GateGeneralParticleSource, and more precisely, its 
> GeneratePrimaryVertex method is the concrete descendent of the
> G4VPrimaryGenerator GEANT4 class which is the class to derive to the 
> particle generation. It may be the point where to implement a parser 
> from external generator and Geant4. I think that one should implement 
> a new GateExternalXXXGenerator which derive from G4VPrimaryGenerator 
> and which shoould be implemented, following the user request, instead 
> of the GateGeneralParticleSource.
>
> I hope this will helps,
>
>    David
>
>

oups, I read again the Ross' message and realize that I misunderstood 
your comment. I think we agree that an external generator have to 
produce hits which will be import to the G4 particle gun (according to 
what you said). I never worked with the GateGeneralParticleSource class, 
do you think that it's the good place to commit the changes ?

By

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**  David GUEZ                                                 **
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