38MaintenanceTo ensure the fault-free operation of the microscope the following instruc-tions for maintenance have to be followed.Scan headIt is very important to prevent the sample holder and the open part of thescanner from becoming dirty or damp.• The sample holder is made of magnetic steel therefore it suffers fromcorrosion in a humid environment. To reduce corrosion and increase lifeexpectancy, the sample holder must be stored in its container togetherwith the moisture absorbing silica container.The container is waterproof but not airtight. The silica contains a blueindicator which turns pink when saturated. It can be regenerated by heat-ing the silica container @ 100°C for at least two hours until it turnscompletely blue again.• If you touch the metal part of the sample holder or it does not movefreely, clean it with a soft cloth, if necessary moistened with alcohol.During cleaning, move the cloth along the sample holder in the axialdirection, do not move it around its circumference.M AINTENANCE