cryogen

詳細解釋：

cry.o.gen

n.（名詞）
A liquid, such as liquid nitrogen, that boils at a temperature below about 0 K (-'0=C) and is used to obtain very low temperatures; a refrigerant.
致冷劑：一種液體，如液化氮，大約在0K（攝氏-'0度）以下的溫度時發生汽化，被用來獲取極低的溫度；冷凍劑