Viewing Windows
In order to view what is in the hot cell, cameras can be used (but these require replacing on a regular basis) or most commonly, lead glass is used. There are several densities for lead glass, but the most common is 5.2 g/cc. A rough calculation for lead equivalence would be to multiply the Pb thickness by 2.5 (e.g. 10mm Pb would require a 25mm thick lead glass window). Older hot cells used ZnBr2 solution in a glass tank to shield against high-energy gamma rays. This shielded the radiation without darkening the glass (as happens to leaded glass with exposure). This solution also "self-repairs" any damage caused by radiation interaction, but leads to optical distortion due to the difference in optical indices of the solution and glass.
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Famous quotes containing the words viewing and/or windows:
“Beguile the time, and feed your knowledge
With viewing of the town.”
—William Shakespeare (1564–1616)
“Among a hundred windows shining
dully in the vast side
of greater-than-palace number such-and-such
one burns
these several years, each night
as if the room within were aflame.”
—Denise Levertov (b. 1923)