Common Numerical Values for Correction of Neutron Scattering Data.
Vanadium-niobium null alloy
The vanadium-niobium null alloy currently in use at ISIS has a composition of 5.14 atomic% Nb.
My best estimate of the lattice parameter is 3.042 7Å, based on many literature values for the lattice parameters of the elements, and use of Vegard's law. This results in a density of 0.07100 atom Å-3 or 6.260 g cm-3.
The V-Nb rod used on the GEM diffractometer with nominal diameter 8mm has a measured radius of 0.3975 cm.
Literature values for the density of vanadium vary wildly.
My best estimate of the lattice parameter, based on many literature values, is 3.0285 Å. This results in a density of 0.07200 atom Å-3 or 6.091 g cm-3.
The vanadium rods used on the GEM diffractometer have the following dimensions:
|Nominal rod diameter||
|6 mm||0.6007 cm||0.30035 cm|
|8 mm||0.8030 cm||0.4170 cm|
|10 mm||0.9858 cm||0.4929 cm|
For a foil thickness of 40 microns, the standard cylindrical vanadium foil cans used on GEM have these dimensions:
|Nominal can diameter||
|5 mm||0.25 cm||0.254 cm|
|6 mm||0.3 cm||0.304 cm|
|8.3 mm||0.415 cm||0.419 cm|
|10.3 mm||0.515 cm||0.519 cm|
Silica glass, v-SiO2
The average of many literature density values, excluding obvious outliers, is 2.2033 g cm-3, equivalent to 0.06625 atom Å-3.