Conversion between Reciprocal Space Vector and Angle
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According to Bragg Condition of electron elastic scattering, the reciprocal space vector q (nm-1) in reciprocal space in an electron microscope (e.g TEM and STEM) follows the small-angle Bragg law,
-------------------------------- [1196]
where,
Θ -- The total scattering angle (in rad) between the incident and scattered beam,
θ -- The Bragg angle (in rad), (see page3882)
λ -- The electron wavelength at a specific acceleration voltage (nm). (see page4787)

Based on Equation 1196, Table 1196 can be obtained.

 Table 1196. Conversion between reciprocal space vector and angle at different accelerating voltages. 1 rad = 1000 mrad.
Angle (Θ)
Reciprocal space vector (q, nm-1)
(mard)
(degree, °)
10 keV
50 keV
80 keV
100 keV
200 keV
300 keV
400 keV
5 0.3 0.4 0.9 1.2 1.3 2.0 2.5 3.0
10 0.6
0.8 1.9 2.4
2.7 4.0 5.1 6.1
20 1.1 1.6 3.7 4.8 5.4 8.0 10.2 12.2
30 1.7 2.5 5.6 7.2 8.1 11.9 15.2 18.3
40 2.3 3.3 7.5 9.6 10.8
15.9 20.3 24.3
50 2.9 4.1 9.3 11.9 13.5
19.9 25.4 30.4
60 3.4 4.9 11.2 14.3 16.2
23.9 30.5 36.5
70 4.0 5.7 13.0 16.7 18.9 27.9 35.5 42.6
80 4.6 6.5 14.9 19.1 21.6 31.9 40.6 48.7
90 5.2 7.4 16.8
21.5 24.3 35.8 45.7 54.8
100 5.7 8.2 18.6 23.9 27.0 39.8 50.8 60.8
110 6.3 9.0 20.5 26.3 29.7 43.8 55.8 66.9
120 6.9 9.8 22.4 28.7 32.4 47.8 60.9 73.0
130 7.5 10.6 24.2 31.1 35.1 51.8 66.0 79.1
140 8.0 11.4 26.1 33.5 37.8 55.8 71.1 85.2
150 8.6 12.3 27.9 35.8 40.4 59.7 76.2 91.3
160 9.2 13.1 29.8 38.2 43.1 63.7 81.2 97.3
170 9.7 13.9 31.7 40.6 45.8 67.7 86.3 103.4
180 10.3 14.7 33.5 43.0 48.5 71.7 91.4 109.5
190 10.9 15.5 35.4 45.4 51.2 75.7 96.5 115.6
200 11.5 16.3 37.3 47.8 53.9 79.7 101.5 121.7

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