Material
|
Temperature range (K)
|
Comments
|
(A) Capillary tubes
|
Glass
|
< 773
|
Lindemann glass scatters less, but is moisture sensitive
Thinner walled tubes that are less sensitive to atmospheric influences can be obtained using other types of glass
|
Lindemann glass
|
< 773
|
Vitreous silica
|
< 1373
|
Collodion
|
93 to 343
|
These capillaries can be made by coating a copper wire with a solution of the polymer in an appropriate organic solvent. When dry, the metal core may be removed by stretching, to reduce its diameter
|
Polyvinyl methylal resin (e.g. Formvar)
|
< 323
|
Cellulose acetate
|
< 373
|
Polyethylene
|
< 373
|
Tubes may be drawn from the molten polymer using a glass tube and a slow stream of air. The polymer gives a distinct diffraction pattern
|
(B) Other containers
|
Gelatin capsules
|
< 303
|
Vessels with very thin, 20 µm, windows can be made
|
Methyl methacrylate resin (e.g. Perspex)
|
< 338
|
|
Mica
|
< 1073
|
Mica windows useful in vessels for small-angle scattering, but the wall size is generally thicker, ∼0.3 mm, and there are discrete lines at 10.00, 3.34 and 2.60 Å in the diffraction pattern
|
Regenerated cellulose film (e.g. cellophane)
|
Ambient
|
|
For optimum results, tube diameters should be between 0.3 and 0.5 mm with wall thicknesses of 0.02 to 0.05 mm. The materials listed above, except where stated, give diffuse diffraction patterns. If necessary, control diffraction patterns, recorded only from the capillary or other container, should be taken.
|