In this paper, threshold laser energy for initiation of micro-explosives, silver-azide(AgN3) of size 1.5 mm in diameter and 1.5 mm in length, has been studied using two experimental methods to verify their results each other. First one was a method that decreases laser beam intensity by neutral density filters. The other one was a method that diverges laser beam by concave lens. A small pulsed Nd : YAG laser, wavelength 1064 nm irradiation, was used in this study. The two results were well agreed, that was 3.57 ± 0.41 mJ / cm2. We also focused on delay time of initiation at the energy of near threshold. Travel times of blast wave by detecting overpressure of incident shockwave, were compared between in the case of enough energy and in the case of slightly over the threshold energy for initiation. Visualization of explodes were also done by double exposure holographic interferometer. Any initiation delay, however, were not found in this study.
アジ化銀ペレット(10 mg, 直径1.5 mm, 長さ1.5 mm)にNd:YAGレーザ光(パルス発振,波長1064 nm, 出力14 mJ / pulse)を照射して起爆させる最小起爆エネルギー(しきい値)を実験的に求めた｡ 実験は, 光強度を減光フィルタを用いて低下させて起爆しきい値を求める方法と, 平凹レンズでレーザ光を拡散して起爆の可否を測定する2種類の方法実施し, ほぼ一致する値を得た。 起爆しきい値は3･57 ± 0･14 mJ / cm2であった。 また, 爆風圧の時間履歴を測定と二重露光ホログラフィ干渉計で爆発様態の可視化をし, 起爆しきい値近傍のレーザ光照射でも有意な起爆遅れが発生しないことを確認した｡ 今後, 起爆しきい値のレーザ光波長依存性についての検討をする｡