Feature Request: Add option to input Debye-Waller factor in GDOS

[mducle]

Summary

To compute the general neutron weight vibration density of states, GDOS, MSlice uses the standard incoherent approximation (last equation in the bullet point list here) but omits the Debye-Waller (DW) factor due to thermal motions of the atoms - it does require the temperature in order to account for the thermal population but neglects thermal displacements.

One common approximation is to use a scalar mean-square displacement parameter - this is used in the ComputeIncoherentDOS algorithm in Mantid (docs here - this also includes the equation for the DW-factor with code here). This parameter (also called Uiso) can be obtained from diffraction data using Rietveld refinement.

MSlice should have a way for users to input this parameter when outputting GDOS type intensity.

Currently, when users select GDOS, a pop-up appears asking for them to input a temperature or the log name of the temperature variable. The DW-factor could also be included with this pop-up.

Alternatively, there could be an additional text edit box in the main Cut and/or Slice tabs.