More inelastic materials for data library

[tkittel]

Very soon the big NCrystal v2.0 release will be out, with new capabilities for inelastic physics. It will contain many materials with phonon-dos or scattering kernels, but due to time limitations there will be more work to do on the data library after the release (but I don't want to delay the release further at this point).

• Only ~half of the materials in both the old NCrystal data library have now has phonon-dos data added to them. This process should be continued.
• More materials from ENDF/B-VIII can be converted (or have VDOS extracted) + have their crystal structures added (polymers need special attention due to multi-phase nature). This includes Polyethylene, Plexiglass, UN, UO2, SiC, ICE, YH2, ZrH.

Opening this issue so we don't forget.

[tkittel]

Related to this, we could also dig out more reference data for the data library wiki page (several materials are currently added without comparison with data).

[tkittel]

For instance, Steyrl1974 also provides more data for graphite totat xs at low energies (which actually conflicts with the trouble-some data from Egelstaff).

[tkittel]

The upcoming NCrystal v2.6.0 release will introduce a lot of new phonon density data (almost tripling the number of vdos curves in the data library), bringing proper inelastic physics to almost all crystalline materials in the data library.

[tkittel]

Release 2.6.0 is out, closing here.

https://github.com/mctools/ncrystal/releases/tag/v2.6.0