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.
Read more about this topic: Hot Cell
Famous quotes containing the words viewing and/or windows:
“The happiest youth, viewing his progress through,
What perils past, what crosses to ensue,
Would shut the book, and sit him down and die.”
—William Shakespeare (1564–1616)
“In winter we lead a more inward life. Our hearts are warm and cheery, like cottages under drifts, whose windows and doors are half concealed, but from whose chimneys the smoke cheerfully ascends.... We enjoy now, not an Oriental, but a Boreal leisure, around warm stoves and fireplaces, and watch the shadow of motes in the sunbeams.”
—Henry David Thoreau (1817–1862)