Ionizing
Radiation
Division

Measurement of Nb for a deuterated polystyrene film

 

Results

Thickness (cm)	Phase shift exp (rad)	Scattering length density Nb (atoms/cm2)
4.80(20) × 10-5	0.400(4)	6.64(28) ×  1010

• Nb is directly proportional to the phase shift. From this it is possible to obtain N and therefore the mass density .

• The uncertainty in Nb is due mainly to the uncertainty in the film thickness.

• The relative standard uncertainty of the phase shift is 1%.

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  Online: November 1998