Optics and Precision Engineering, Volume. 33, Issue 12, 1876(2025)
Design of a quasi-parallel beam electron gun with micro beam spot for Reflection High Energy Electron Diffraction
Figures & Tables(16)
Fig. 3. Simulated structure of the RHEED electron gun and the electron beam trajectory
Fig. 4. Internal structure and actual image of the experimental platform for RHEED electron gun
Fig. 6. Beam current distribution curves at different accelerating voltages
Fig. 8. Fitting of the acquired beam current curve at an accelerating voltage of 30 kV
Fig. 9. Spot diameter （FWHM） measured at different accelerating voltages
Fig. 12. RHEED pattern of the highly oriented pyrolytic graphite （HOPG）
Table 1. Performance of RHEED magnetic lens at different lens positions
View tableView in ArticleTable 1. Performance of RHEED magnetic lens at different lens positions
Lens position/mm M dg/μm ds/μm dc/μm dλ/μm di/um αo/mrad 50 -10.76 81.45 0.025 0.007 0.019 81.46 2.15 60 -8.90 67.33 0.021 0.006 0.019 67.33 1.78 70 -7.58 57.37 0.018 0.005 0.019 57.37 1.52 80 -6.60 49.98 0.016 0.004 0.019 49.98 1.32 90 -5.85 44.27 0.014 0.004 0.019 44.27 1.17 100 -5.25 39.73 0.013 0.004 0.019 39.73 1.05
Table 2. Performance of RHEED magnetic lens at different
S /D View tableView in ArticleTable 2. Performance of RHEED magnetic lens at different
S /D S/D Lens current/A dg/μm ds/μm dc/μm dλ/μm di/um αo/mrad 0.3 523.58 44.83 0.012 0.004 0.019 44.83 1.29 0.4 492.79 44.83 0.016 0.004 0.019 44.83 1.29 0.5 448.04 44.83 0.022 0.004 0.019 44.83 1.29 0.6 417.15 44.84 0.029 0.004 0.019 44.84 1.29 0.7 394.65 44.85 0.037 0.004 0.019 44.85 1.29
Table 3. Simulation results on the properties of RHEED electron gun with different accelerating voltages
View tableView in ArticleTable 3. Simulation results on the properties of RHEED electron gun with different accelerating voltages
Accelerating voltages/kV do/μm Brightness
/（105 A·cm-2·sr-1）
Emission current/μA Lens current/At αo
/mrad
dg
/μm
ds
/μm
dc
/μm
dλ
/μm
di
/um
10 10.86 0.32 2.99 284.51 1.29 69.84 0.016 0.013 0.033 69.84 15 9.25 0.82 5.5 348.06 1.29 59.55 0.016 0.008 0.027 59.55 20 8.23 1.6 8.57 401.64 1.29 52.98 0.016 0.006 0.023 52.98 25 7.64 2.5 11.62 448.82 1.29 49.18 0.016 0.005 0.021 49.19 30 6.97 4.2 16.15 491.85 1.28 44.63 0.016 0.004 0.019 44.64
Table 4. Electron beam half-angles at different positions
View tableView in ArticleTable 4. Electron beam half-angles at different positions
Sampling location/mm di/μm αi/mrad 0 127.69 — 5 125.97 0.172 10 124.23 0.346 15 125.20 0.249 20 124.80 0.289 25 123.82 0.387 均值 — 0.289
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Weixia ZHAO, Lina SHI, Junbiao LIU, Bohua YIN, Li HAN. Design of a quasi-parallel beam electron gun with micro beam spot for Reflection High Energy Electron Diffraction[J]. Optics and Precision Engineering, 2025, 33(12): 1876
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Received: Mar. 10, 2025
Accepted: --
Published Online: Aug. 15, 2025
The Author Email: Junbiao LIU (liujb@mail.iee.ac.cn)
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