Hi,

 

the larch xraydb plugin doesn't provide correct numbers for chantler f1 data around edges.

Apparently this is due to incorrect interpolation in xray/xraydb.py in line 274.

Below is a plot of "delta" from xraydb_plugin.xray_delta_beta() for Silicon which is terrribly wrong.

 

 

The more correct "delta" as from chantler is shown in the following plot:

 

 

--> I'd recommend to replace (line 274 in plugin xray/xraydb.py):

 

out = UnivariateSpline(te, ty, s=smoothing)(energy)

 

by a simple linear interpolation

 

out = np.interp(energy, te, ty)

 

The latter yields linear segments between chantler's data, but this is still better than the totally unphysical spline interpolation.

 

Best regards,