Coherent Backscattering from Multiple Scattering Systems - KOPS ...

5.2 The coherent backscattering cone in high resolution
intensity [a.u.]
1
0.8
0.6
0.4
0.2
1 mm
2 mm
3 mm
4 mm
5 mm
6 mm
7 mm
9 mm
10 mm
11 mm
12 mm
13 mm
14 mm
15 mm
16 mm
0
0 0.02 0.04 0.06 0.08 0.1
scattering angle [deg]
normalized intensity
1
0.8
0.6
0.4
0.2
1 mm
2 mm
3 mm
4 mm
5 mm
6 mm
7 mm
9 mm
10 mm
11 mm
12 mm
13 mm
14 mm
15 mm
16 mm
0
0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04
scattering angle [pixels]
Figure 5.11: Focus accuracy. The position of the focussing lens was varied in a range
of 16 mm around its nominal position 50 cm in front of the CCD camera. The lens
is positioned correctly when the width of the teflon backscattering cone (top) and the
mirror spot (bottom) is minimal, i.e. between 7 and 10 mm. For higher numbers the lens
is too close to the camera, for lower numbers it too far away. (To make the measurements
easier to compare the data were scaled to have intensities between 0 and 1.)
59