Add KT3 diagnostic

[Mateasek]

KT3 is used to validate SOLPS simulations for impurity puffing. The model will be based on FibreOptic observers.

[vsnever]

Thanks for rising this. I'm also interested in having KT3 in the JET module. Do you already have an implementation? I'm asking because it looks like this diagnostic is implemented in the tool developed by Bart Lomanowski, and some analysis for KT3 and KT1 has already been done using the Cherab, https://doi.org/10.1088/1361-6587/ab7432. I was thinking about asking his permission to move his implementation to the official Cherab module for JET.

Also, will these additions, cherab/core#284, help implement this diagnostic?

[Mateasek]

All I know was there were some attempts to model the diagnostic with sight-lines with the cherab-omfit package. My Idea was to use JET ppf files (pulse number and time) to allow the user to get the diagnostic set automatically. There will be a way how to set it up without using the ppf files (for people without JET access and tests). I looked into the issue cherab/core#284 and it could be useful, I completely missed this issue.

[vsnever]

My Idea was to use JET ppf files (pulse number and time) to allow the user to get the diagnostic set automatically. There will be a way how to set it up without using the ppf files (for people without JET access and tests).

At least in case of KS3, jpf/ppf will give only the reference wavelength. Are you going to use IDL bridge for calculating spectrometer resolution, etc? If no, then the functions that do this will be useful for other diagnostics as well. However, as far as I know, some diagnostic parameters are hardcoded in the IDL routines.

[Mateasek]

I made this issue to inform the developers that my intention is to start working on the model. So far I looked into ppfs and it seems they contain all the needed information (origins, observation points, wavelengths, mirror shifts) to create a simple version of the model. If there is a better source of informatio (through the idl bridge for example), I will add it in the 2nd round.

What did you mean by the resolution calculation?