GPS extra primaries

Particles, Track, Event, Run and Biasing
1

Dear experts,

I prepared a macro with the following instructions to simulate a double uniform source using GPS.

### First source
/gps/source/add 1.
/gps/particle e-
/gps/pos/type Plane
/gps/pos/shape Square
/gps/ene/mono 10 MeV
/gps/pos/centre 100 100 100 mm
/gps/pos/halfx 100 mm
/gps/pos/halfy 100 mm
/gps/direction 0 0 -1

### Second source
/gps/source/add 1.
/gps/particle e-
/gps/pos/type Plane
/gps/pos/shape Square
/gps/ene/mono 10 MeV
/gps/pos/centre 100 100 0 mm
/gps/pos/halfx 100 mm
/gps/pos/halfy 100 mm
/gps/direction 0 0 1

/gps/source/list

In contrast, it appears that some neutral particles are also launched as primary particles alongside electrons (here is an example, one green track originates at (0,0,0) and goes in -Z direction):

image

Is there something in the macro related to GPS that is missing?

2

what is the output of that command?

3

The output of /gps/source/list is:

The number of particle sources is: 3
 Multiple Vertex sources: 0 Flat Sampling flag: 0
    source 0 with intensity: 1
         Num Particles: 1; Particle type: geantino
         Energy: 1 MeV
         Direction: (0,0,-1); Position: 0 0 0 fm 
         Angular Distribution: planar
         Energy Distribution: Mono
         Position Distribution Type: Point; Position Shape: NULL
    source 1 with intensity: 1
         Num Particles: 1; Particle type: e-
         Energy: 1 MeV
         Direction: (0,0,-1); Position: 10 10 10 cm 
         Angular Distribution: planar
         Energy Distribution: Mono
         Position Distribution Type: Plane; Position Shape: Square
    source 2 with intensity: 1
         Num Particles: 1; Particle type: e-
         Energy: 1 MeV
         Direction: (0,0,1); Position: 10 10 0 cm 
         Angular Distribution: planar
         Energy Distribution: Mono
         Position Distribution Type: Plane; Position Shape: Square
4

P.s. I also prepared a macro with the following instructions for a single source:

/gps/particle e-
/gps/pos/type Plane
/gps/pos/shape Square
/gps/ene/mono 10 MeV
/gps/pos/centre 100 100 100 mm
/gps/pos/halfx 100 mm
/gps/pos/halfy 100 mm
/gps/direction 0 0 -1

In this case, I don’t observe any neutral particle as primary, and the output of /gps/source/list is:

The number of particle sources is: 1
 Multiple Vertex sources: 0 Flat Sampling flag: 0
    source 0 with intensity: 1
         Num Particles: 1; Particle type: e-
         Energy: 1 MeV
         Direction: (0,0,-1); Position: 10 10 10 cm 
         Angular Distribution: planar
         Energy Distribution: Mono
5

there is an additional „geantino“ source. check the macro files or the code :slight_smile:

6

Thank you for your reply, with this macro (without the /gps/source/add 1. in the first line):

### First source
/gps/particle e-
/gps/pos/type Plane
/gps/pos/shape Square
/gps/ene/mono 10 MeV
/gps/pos/centre 100 100 100 mm
/gps/pos/halfx 100 mm
/gps/pos/halfy 100 mm
/gps/direction 0 0 -1

### Second source
/gps/source/add 1.
/gps/particle e-
/gps/pos/type Plane
/gps/pos/shape Square
/gps/ene/mono 10 MeV
/gps/pos/centre 100 100 0 mm
/gps/pos/halfx 100 mm
/gps/pos/halfy 100 mm
/gps/direction 0 0 1

everything works fine and there is no more the geantino source.

7

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