[Gate-users] Change orientation of cone volume
Christopher Watanabe
chris.r.watanabe at gmail.com
Sat Sep 14 09:09:34 CEST 2019
Hello Matthew (and all),
First, I did try to setRotationAngle / Axis with specific values as Matthew
indicated in the last post. However, this did not change the primary axis
of the cone.
Second, the problem I think has to do with the cone being the daughter of
another volume. So, to get the cone to rotate, you have to rotate the
parent! See the code below, I first declare the parent "collimator" with
dimensions to fit the wrongly oriented cone. Then rotate the parent (and
therefore all children) to be in the correct orientation. The volume *front*
is previously declare and is simply an Air filled volume at the head of my
SPECT device.
## Collimator
/gate/front/daughters/name collimator
/gate/front/daughters/insert box
/gate/collimator/geometry/setXLength 44. mm
/gate/collimator/geometry/setYLength 44. mm
/gate/collimator/geometry/setZLength 11.14 mm
/gate/collimator/placement/setTranslation 0. 0. 0. mm
/gate/collimator/setMaterial Air
# Square of tungsten with correct thickness at the wider base (crystal
side)
/gate/collimator/daughters/name base
/gate/collimator/daughters/insert box
/gate/base/geometry/setXLength 44. mm
/gate/base/geometry/setYLength 44. mm
/gate/base/geometry/setZLength 1. mm
/gate/base/placement/setTranslation 0. 0. 5.07 mm
/gate/base/setMaterial Tungsten
# Cone of tungsten for collimation
/gate/collimator/daughters/name Tcone
/gate/collimator/daughters/insert cone
/gate/Tcone/geometry/setRmin1 2 mm
/gate/Tcone/geometry/setRmax1 3 mm
/gate/Tcone/geometry/setRmin2 21 mm
/gate/Tcone/geometry/setRmax2 22 mm
/gate/Tcone/geometry/setHeight 10.14 mm
/gate/Tcone/placement/setTranslation 0. 0. -1. mm
/gate/Tcone/setMaterial Tungsten
# This is our solution!
/gate/collimator/placement/setRotationAxis 1 0 0
/gate/collimator/placement/setRotationAngle 90 deg
[image: image.png]
Follow up question: Above I declare a "base", which is this square plate at
the base of the pinhole collimator. This means that particles have to
penetrate that base plate to get to the crystal. If I declare a cone of air
as a daughter of the colllimator, does it displace the base plate where
they intersect?
Chris
On Fri, Sep 13, 2019 at 7:02 PM Matthew Strugari <matthew.strugari at dal.ca>
wrote:
> Hi Chris,
>
> Have you tried specifying the rotation axis and angle with numerical
> values?
>
> /gate/Tcone/placement/setRotationAxis 1 0 0
> /gate/Tcone/placement/setRotationAngle 90 deg
>
> Cheers,
> Matthew
>
> > On Sep 13, 2019, at 7:10 AM, Christopher Watanabe <
> chris.r.watanabe at gmail.com> wrote:
> >
> > Hi everyone,
> >
> > I'm trying to create a pinhole collimater. So far, I have everything set
> up well, but the orientation is wrong with the preexisting orientation of
> the camera. (i.e. the primary axis of the pinhole should be the normal of
> the pixel grid)
> >
> > The code I have now is:
> >
> > ## Volume at the front of the spect device for the collimator
> >
> > /gate/front/daughters/name collimator
> > /gate/front/daughters/insert box
> > /gate/collimator/geometry/setXLength 44. mm
> > /gate/collimator/geometry/setYLength 11.14 mm
> > /gate/collimator/geometry/setZLength 44. mm
> > /gate/collimator/placement/setTranslation 0. -0.2 0. mm
> > /gate/collimator/setMaterial Air
> >
> > # Square of tungsten with correct thickness at the wider base (crystal
> side)
> > /gate/collimator/daughters/name base
> > /gate/collimator/daughters/insert box
> > /gate/base/geometry/setXLength 44. mm
> > /gate/base/geometry/setYLength 1 mm
> > /gate/base/geometry/setZLength 44. mm
> > /gate/base/placement/setTranslation 0. -0.2 0. mm
> > /gate/base/setMaterial Tungsten
> >
> > # Cone of tungsten for collimation
> > /gate/collimator/daughters/name Tcone
> > /gate/collimator/daughters/insert cone
> > /gate/Tcone/geometry/setRmin1 0 mm
> > /gate/Tcone/geometry/setRmax1 3 mm
> > /gate/Tcone/geometry/setRmin2 0 mm
> > /gate/Tcone/geometry/setRmax2 25 mm
> > /gate/Tcone/geometry/setHeight 11.14 mm
> > /gate/Tcone/placement/setTranslation 0. -0.2 0. mm
> > /gate/Tcone/setMaterial Tungsten
> >
> > # Cone of Air within the cone of tungsten
> > /gate/Tcone/daughters/name hole2
> > /gate/Tcone/daughters/insert cone
> > /gate/hole2/geometry/setRmin1 0 mm
> > /gate/hole2/geometry/setRmax1 2 mm
> > /gate/hole2/geometry/setRmin2 0 mm
> > /gate/hole2/geometry/setRmax2 24 mm
> > /gate/hole2/geometry/setHeight 11.14 mm
> > /gate/hole2/placement/setTranslation 0. -0.2 0. mm
> >
> > So, basically, the hollow tungsten cone should be within the air volume
> allocate for the collimator. The primary axis of the cone is along the z
> direction though, so I get the following visualization:
> >
> > <image.png>
> > As you can see, the solid red cone (pinhole) is oriented along the
> z-axis, whereas the rest of the SPECT device is oriented along the y axis...
> >
> > Things I've tried:
> > /gate/Tcone/placement/alignToY - This command just centers it along the
> y axis. Doesn't change the primary axis.
> > /gate/Tcone/placement/setRotationAxis +
> /gate/Tcone/placement/setRotationAngle - Also doesn't yield any helpful
> changes.
> >
> > I'd appreciate any help!
> >
> > Cheers!
> >
> > Chris
> >
> > _______________________________________________
> > Gate-users mailing list
> > Gate-users at lists.opengatecollaboration.org
> > http://lists.opengatecollaboration.org/mailman/listinfo/gate-users
>
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