Program

Poster Presentations

Day 3, June 12（Fri.）　　Room P (5F 501+502)

3P-17

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Improvements for Helium Isotope Imaging using LIMAS

(¹Hokkaido Univ., ²ISAS)
^oKen-ichi Bajo¹, Sohei Wada^1,2, Hisayoshi Yurimoto¹

Laser Ionization Mass Nanoscope enables multi-isotope analysis, including noble gases, with high lateral and depth resolution. It has been applied to 2-D and 3-D helium imaging in cosmochemistry. However, the imaging area has been limited by the focused spot size of the femtosecond (fs) laser. The focusing lens position is controlled along the X (depth), Y (parallel to the surface), and Z (perpendicular) axes. Because the focal point can move parallel to the surface, the imaging area can potentially be expanded. Here, we scanned the fs laser focusing lens to extend the imaging area and evaluated the maximum attainable size. Isotope imaging was performed on a ⁴He-implanted Si substrate. A 320 × 320 µm² area was analyzed using Ga ion beam. In lens-synchronization mode, the Y-axis lens position was shifted to match the primary beam; lens-fix mode served as comparison. High-intensity regions (≥80% of maximum) increased from 3,950 to 12,770 µm² for ⁴He, corresponding to 3.2× expansion.

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