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Bug #1951

LiH Geometry Bug

Added by Rogers, Chris over 3 years ago. Updated over 3 years ago.

Status:
Open
Priority:
Normal
Category:
Geometry
Target version:
Start date:
22 January 2018
Due date:
% Done:

0%

Estimated time:
Workflow:
New Issue

Description

I did some digging on the LiH geometry...

  • Absorber vacuum windows are in place which should not be I think. If they were installed (I guess check with Colin), then use a polycone not the tesselated solid as implemented, to fix the weirdness. The offending geometries are in AFC.gdml as AlAlloy6061_Element_Step_24 and AlAlloy6061_Element_Step_25.
  • The LiH absorber has a ~ 60 mrad misalignment. This seems rather a lot (around 20 mm between one side of the absorber and the other). I rather suspect this is a bug?

Files

LiH_in_materials.png (23.6 KB) LiH_in_materials.png Image of the asborber as implemented in G4 with absorber installed. Rogers, Chris, 22 January 2018 11:44
materials.png (19.5 KB) materials.png Image of the absorber region with no absorber installed Rogers, Chris, 22 January 2018 11:59
check_geometry.py (3.46 KB) check_geometry.py Rogers, Chris, 22 January 2018 13:12
materials-EmptyLiH-10299.png (19.4 KB) materials-EmptyLiH-10299.png Rajaram, Durga, 22 January 2018 15:39
materials-LiH-10476.png (22.6 KB) materials-LiH-10476.png Rajaram, Durga, 22 January 2018 15:39
#1

Updated by Rogers, Chris over 3 years ago

Note the windows are also on the "empty" geometry

#2

Updated by Rajaram, Durga over 3 years ago

I agree I doubt they were installed for the lih running.
How about I take those elements out of the LiH & empty-LiH geometries?
And then if Colin says they should be there, do a correct implementation?

& can you post the script you use to make the pretty plot?

#3

Updated by Rogers, Chris over 3 years ago

...attached...

#4

Updated by Rajaram, Durga over 3 years ago

Took the Al window physical volumes out of the AFC gdml.

I think the misalignment might be stemming from the issue you found earlier with the LH2 geometry where there was a rotation put in.
I have taken that out for the LiH geometries (Nov/Dec 2017 periods)

For the empty LiH, I've left the Mylar foil in there -- not sure if that belongs.

The geometries are in preprod

LiH-Empty:

python bin/utilities/download_geometry.py -geometry_download_run_number 10299 -geometry_download_directory geo-10299 -cdb_download_url "http://preprodcdb.mice.rl.ac.uk/cdb/" 

LiH:

python bin/utilities/download_geometry.py -geometry_download_run_number 10476 -geometry_download_directory geo-10476 -cdb_download_url "http://preprodcdb.mice.rl.ac.uk/cdb/" 

Will push to prod if you OK it

#5

Updated by Rogers, Chris over 3 years ago

I checked by eye and the geometries look okay to me now - thanks!

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