Absorption cell with removable windows

Claim 1

AN ABSORPTION CELL COMPRISING A RIGID HOUSING DEFINING A HOLLOW PARALLELEPIPED AND AN INSERT DEFINING A SLIGHTLY SMALLER HOLLOW PARALLELEPIPED WHICH IS SLIGHTLY SMALLER THAN SAID HOUSING AND RECEIVABLE WITHIN SAID HOUSING WITH A CLOSE FIT, SAID HOUSING INCLUDING A PAIR OF PARALLEL LONGITUDINAL WALLS WHICH ARE OPPOSED TO EACH OTHER DEFINING OPENINGS THEREIN AND SAID INSERT INCLUDING A PAIR OF LONGITUDINAL WALLS WHICH ARE OPPOSED TO EACH OTHER DEFINING A PAIR OF OPENINGS OPTICALLY ALIGNED WITH THE OPENINGS IN SAID HOUSING WALLS WHEN SAID INSERT IS DISPOSED WITHIN SAID HOUSING, A PAIR OF OPTICALLY FLAT QUARTZ WINDOWS DEFINING A SHAPE SIMILAR TO BUT SLIGHTLY LARGER THAN THE OPENINGS IN SAID HOUSING DISPOSED AGAINST THE INNER SURFACES OF SAID LONGITUDINAL WALLS OF SAID HOUSING SUPEROSED OVER THE OPENINGS IN SAID HOUSING AND MAINTAINED IN PARALLEL SEALING RELATIONSHIP THEREAGAINST BY SAID INSERT TO THEREBY FORM A PAIR OF OPTICALLY ALIGNED WINDOWS IN THE CELL.