Table 1. Winston-Lutz QA outcomes for three beamline setups.

The distance of the ballbearing to the beam isocentre was captured via radiochromic film in the X, Y and Z axes. Measurement uncertainties (as described in Section 2.4.1) are shown for each axis; the three errors are combined in quadrature to give the total uncertainty in the 3D measurement.

	Distance to isocentre (mm)
	X (±0.050)	Y (±0.050)	Z (±0.050)	3D (±0.087)
Beamline setup 1	0.013	0.037	0.167	0.171
Beamline setup 2	0.041	0.032	0.049	0.074
Beamline setup 3†	0.331	0.543	0.780	1.007

^†This result highlights an error in the beamline setup.