南極の氷の光学特性は,0.8~1キロメートルの深さにある
まとめ
南極の氷は極めて透明で,可視光の吸収長さは59メートルである. この極度の澄み,in situで測定され,実験室の氷を上回り,超純水質に匹敵する.
科学分野:
- 氷河学 氷河学とは
- 光学物理学 光学物理学
- 中性子天文学 中性子天文学
背景:
- 南極の深い氷の光学的な性質は,南極ミューオンと中性子検出器配列 (AMANDA) のような中性子検出器にとって極めて重要です.
- 氷の光の吸収と散乱を理解することは,チェレンコフ放射信号の解釈に不可欠です.
研究 の 目的:
- 南極の氷の奥深くにある可視光のインシット吸収と散乱の長さを測定するために.
- この氷の光学特性を超純水と実験用氷と比較するために.
主な方法:
- アマンダ・ニュートリノ検出器のレーザー校正システムを用いたインシットー測定.
- 0.8〜1キロメートルの深さでの調査で,可視光 (約. 515 nm) である.
主要な成果:
- 氷は固有の極度の透明性を示し,吸収の長さは59 ± 3メートルと測定されています.
- この吸収の長さは,超純水と同等であり,最高の実験用氷の2倍以上である.
- 空気泡による散乱が観察され,逆散乱の長さは深さとともに線形に減少した.
結論:
- 深い南極の氷は,光の伝播のための例外的に透明な媒介です.
- 空気泡の存在は光子散乱に影響しますが,氷の本質的な透明性は顕著です.
- これらの発見は,中性子天文学の光学測定のための深い氷の使用を検証します.
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