low-background steel

== English == === Etymology === Ellipsis of low background radiation steel. === Noun === low-background steel (countable and uncountable, plural low-background steels) Steel with low inherent radiation levels, suitable for instruments and experiments highly sensitive to radiation. Steel created before 1945, and not contaminated by radioisotopes originating from nuclear bomb tests and explosions, and other nuclear technology radioactivity releases. Used other than figuratively or idiomatically: see low-background,‎ steel.