Electric Field Mesh Size

Simulation / Configuration Questions
1

I am in the process of defining an electric field manually from comsol data. How should i know how fine to make the mesh? My geometry is 45x45x525 microns per pixel. If it should be done based on the field instead, would you have any suggestion on how its based?

2

Hi @egiunta

the mesh granularity of your converted electric field should depend on the smallest feature size you expect in your electric field. E.g. if you have very small implants (say 2x2um) I would recommend using a binning of 0.5um or similar.

Now with 3D fields, this pretty quickly explodes - but you could start with some more coarse and then produce a finer version and check if you observe differences. Also, some coordinates (such as the very thick z-axis) could be fine already with coarser binning.

In your original COMSOL simulation - what is the finest mesh size observed?

Cheers,
Simon

3

Hi @simonspa, @egiunta

I have a question concerning importing the electric field from COMSOL. So in order to use the mesh converter tool in Allpix2, two files (.dat and .grd) should be given as input. Then, my question is that, in the case of COMSOL, we have the mesh file in another file extension such as (.mphtxt). So what do you suggest in this case?

@egiunta From your experience, how did you manage to import the electric field from COMSOL and use it afterward in Allpix2?

Thanks in advance for your replies
Tasneem

4

Hi @Tasneem

I have not heard back from @egiunta so haven’t worked on this. Do you know what the format of the mphtxtr file is? If we find this out I guess it would be quite simple to add a parser module, I have already started the work to support different input data formats via https://gitlab.cern.ch/allpix-squared/allpix-squared/-/merge_requests/321

Cheers,
Simon

5

Hi @simonspa

Thanks for taking the initiative and start working on providing different input data formats.

A brief description about the mphtxt file is available here
http://victorsndvg.github.io/FEconv/formats/mphtxt.xhtml

and more details about its structure can be found here:
http://victorsndvg.github.io/FEconv/formats/mphtxt.xhtml#fstruc

I hope this would help. Also, it would be possible to provide you with an example of a mphtxt file if needed, please let me know.

Cheers
Tasneem