Patent Number: 040244024
Section: description

FIG. 1 illustrates schematically a specimen table or mount 1 braced against the pole shoe of an objective lens of an electron microscope, the remaining portions of the lens not being illustrated in the drawing. The specimen table 1 is adjustable transversely by means of push rods (FIG. 3) which are operable from outside the microscope. The specimen table 1 has a centric winding opening 3 for accommodating a receiving ring 4 having a conical bore 5. In the bore 5 is placed a specimen cartridge 6 inserted so as to be parallel to the axis of the electron beam. The specimen cartridge 6 is provided with a central passage 7 through which the electron beam may pass. The specimen cartridge 6 has a conical member or cartridge cone 8 to which is joined a specimen holder 9. The specimen holder 9 is rotatable about an axis 11 eccentric to the cone axis 10 and is provided with a plurality of openings 12 for receiving a corresponding number of specimens. In the embodiment illustrated in FIG. 1 the object specimen holder 9 is configured as a circular shaped disk and is equipped with openings 12a for receiving special specimen carriers 13. The specimen carriers 13 hold the specimens and are securely positioned by means of a plate 14 held in tension against the specimen holder 9. The fixation of the position of the specimen holder is achieved by a screw 15 which grips into a winding bore 16 of the shaft 17 carrying the specimen holder 9. The shaft 17 is joined with a gear wheel 18 at a position away from a specimen holder 9. The gear wheel 18 is rotatably held to the end face 20 of the cartridge cone 8 by means of a glide bearing 19. The glide bearing consists of, for example, a ring comprising beryllium-bronze. The ring grips into a ring groove 19a on the gear wheel 18 on the one hand and into a ring groove 19b of a ring 21 constituting a bearing dish on the other hand. The ring 21 is tightly joined with the end face 20 of the cartridge cone 8 via a cap 22. The cartridge cone 8 and therewith the specimen holder 9 extend into a space 23 surrounded by the pole shoe 2. In this space, there is arranged a cooling apparatus 24 joined to the cooling cap 25. The gear wheel 18 has a radius which extends beyond the cone axis 10 and is provided with through-openings 27 corresponding to the opening 12 of the circular shaped disk 9 for accommodating the electron beam. As illustrated in FIG. 2, the gear wheel 18 engages the pinion 28 which is on a drive shaft 29 positioned in the cartridge cone 8 parallel to the cone axis 10. The shaft 29 is joined with a toothed drive wheel 30. The wheel 30 has a diameter such that it extends beyond the periphery of the cartridge cone 8 and engages a toothed wheel in the specimen table 1. FIG. 3 illustrates the specimen table 1 which is transversely adjustable by means of push rods 31, 32 and which centrically holds the cartridge cone 8. The toothed drive wheel 30 engages a toothed wheel 35 which is driven by means of a worm gear 36. The worm gear 36 is positioned on a shaft 37 which is joined with a turning wheel or grip 40 via a length adjuster 38 and an angle drive 39. The turning handle 40 is on a shaft 41 which extends vacuum-tight through the housing 42 of the electron microscope. By adjusting the turning handle 40, the specimens are sequentially spaced in the path of the electron beam. FIG. 4 illustrates a disk shaped specimen holder 9 which is configured to receive four specimen carriers 13. This embodiment permits four specimens to be brought into the interior of the electron microscope simultaneously. FIG. 5 illustrates the specimen holder 9 of FIG. 1 which has slits extending concentric to the turning axis of the disk as illustrated in FIG. 6. In this embodiment, the specimens are placed between the disk shaped specimen holder 9 and a plate 51 tensioned against the latter. The gear wheel 18 has slit-like pass through openings 27 in this embodiment for passage of the electron beam; this embodiment is especially suited for investigating specimens having a large surface area. While the invention has been described by means of specific examples and in a specific embodiment, we do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.