You should prepare working area accordingly. This is very important because particulate contamination from the work surface or the worker is what usually scratches the coating. Clear the table of everything and wear clean clothing. Work as still as possible so as not to shake particles out of your hair while cleaning. Work in a darkened room under a freshly cleaned high intensity desk lamp so that the reflection of a bright source of light on a dark background will allow you to see what you are doing. Be sure that the work surface will not be eaten by methanol. Read all precautions regarding the safe use of methanol and follow all storage and handling instructions. Any area containing optics should prohibit smoking. Smoke vapor deposits are difficult to remove from optical surfaces. Unless otherwise noted, all methods of cleaning (vacuum, dry nitrogen, brush, cotton, and/or ZnSe windows) are performed from the center of the surface to its edges. The applicator (cotton, ZnSe windows) should be rotated as the cleaning advances, always presenting a clean surface to the object being cleaned.
Dust is the most common contaminant and can usually be removed using pressurized gas. If more cleaning is necessary, hold the ZnSe windows in lens tissue and apply a few drops of reagent-grade acetone or ZnSe windows cleaning solution. Slowly turn the ZnSe windows while applying pressure in the center and working outward, to pull dirt off the ZnSe windows instead of redistributing it on the surface. Fingerprints on a coated ZnSe windows should be cleaned as soon as possible to avoid staining or damaging the optic. Larger dirt particles, however, should be removed with a dust-free blower before attempting to clean the optic with ZnSe windows. Larger particles trapped under the cloth will scratch the surface you are attempting to clean. If the ZnSe window is still dirty after using acetone – for instance, if the oil was just redistributed and not cleaned off the optic – then a mild soap solution can be used to gently wash the ZnSe windows. Repeat the procedure with acetone and finish it with isopropyl alcohol to eliminate streaks and soap residue.
This article comes from dmphotonics edit released