The measured values of as a function of l2. The solid circles show the values obtained using IFMRB for l2 < 196 mm2 and IFMD for l2 > 196 mm2. The line shows the best fit to the measured values. The insets show an example of the best-fit calculated IFMD and IFMRB curve to the measured profile for l = 14 mm. The position of the third peak of the measured IFMD is indicated by an arrow in the upper profile and the corresponding calculated position is indicated by an arrow in the lower curve.