Device for illuminating the sample, the sample holder and the cooling bath in an immersion-cryofixation apparatus

摘要

A device for illuminating the sample, the sample holder and the cooling bath (6) in an immersion-cryofixation apparatus, especially for biological samples, in which according to main application P 3332741.6 the illumination of the sample and sample holder positioned above the cooling bath (6) is effected by a vertically upward directed beam (21) of a light source, which beam passes through a window (14') in the bottom of the cooling bath container (5) and through the cooling bath (6). In order to prevent the deposition of frost on the optical parts (window 31, deflecting mirror 22, window 14') through which the beam (21) passes, four different solutions are proposed: a) said parts may be arranged in an enclosed compartment (23) which contains a dry gas or to which a dry gas is admitted; b) the enclosed compartment containing the parts is gastight and largely evacuated; c) at a small distance from the window of the cooling bath there is fixed in a gastight manner a heat barrier filter whose surface can be heated to a sufficiently high temperature, or d) the beam is passed through an optical fibre cable whose exit pupil is joined directly to the window in a gastight manner. The flushing gas according to solution a) can be GN2 evaporating from the LN2 reservoir (4). <IMAGE>