P7.1.2.1 LEYBOLD Physics Leaflets Measuring example a)Bragg reflection at an LiF monocrystal: X-Ray Apparatus 回☒ D色回 Bragg Planck Transmission Moseley log R wl-in Fig.4 Diffraction spectrum of x-rays in Bragg reflection to the third diffrac- n=3 tion order at an LiF monocrystal with logarithmic display of counting 20 30 rate R. 8/ Parameters of x-ray tube: by Leybold Didactic GmbH.1998 U=35 kV,I=1 mA b)Bragg reflection at an NaCl monocrystal: X-Ray Apparatus 问☒ 凸西路色都回 Bragg Planck Transmission Moseley og R Fig.5 Diffraction spectrum of x-rays in Bragg reflection to the third diffrac- tion order at an NaCl monocrystal with logarithmic display of counting 20 0 rate R. 8/ Parameters of x-ray tube: by Leybold Didactic GmbH,1998 U=35 kV,/=1 mA Evaluation In each diagram,click the right mouse button to access the For each glancing angle calculate the values sin and evaluation functions of the software "X-ray Apparatus"and and plot these value pairs in a diagram (see Fig.6). select the command "Calculate Peak Center"to evaluate In each case,the results lie along a straight line through the the diffraction spectra. origin:in accordance with (Ill),its slope corresponds to the Using the left mouse button,mark the "full width"of each lattice constant ao. peak and write down the center values in a table as the glancing angle (see tables 2 and 3).Measuring example a) Bragg reflection at an LiF monocrystal: b) Bragg reflection at an NaCl monocrystal: Evaluation – In each diagram, click the right mouse button to access the evaluation functions of the software “X-ray Apparatus” and select the command “Calculate Peak Center” to evaluate the diffraction spectra. – Using the left mouse button, mark the “full width” of each peak and write down the center values in a table as the glancing angle (see tables 2 and 3). – For each glancing angle q, calculate the values sin q and and plot these value pairs in a diagram (see Fig. 6). In each case, the results lie along a straight line through the origin; in accordance with (III), its slope corresponds to the lattice constant a0. Fig. 4 Diffraction spectrum of x-rays in Bragg reflection to the third diffrac￾tion order at an LiF monocrystal with logarithmic display of counting rate R. Parameters of x-ray tube: U = 35 kV, I = 1 mA Fig. 5 Diffraction spectrum of x-rays in Bragg reflection to the third diffrac￾tion order at an NaCl monocrystal with logarithmic display of counting rate R. Parameters of x-ray tube: U = 35 kV, I = 1 mA P7.1.2.1 LEYBOLD Physics Leaflets 4