JPH0244446Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sample contamination prevention device for preventing contamination of a sample in an electron microscope or the like.

[Prior art] In electron microscopes, etc., the vicinity of the sample is covered with a metal kept at a low temperature to prevent contamination of the sample.
Particles that fly close to the sample and cause contamination are adsorbed and trapped by the metal, thereby preventing contamination of the sample. Figure 2 shows a conventional sample contamination prevention device manufactured to be compatible with, for example, a top entry type sample device. The pole piece unit 2 is integrally assembled with an upper magnetic pole piece 2a of the objective lens and a lower magnetic pole piece 2b of the objective lens facing each other with a spacer 3 in between. Reference numeral 4 denotes a top-entry type sample tube inserted into the receiver of the sample stage 1, and 5 indicates a sample held in the sample tube 4. Reference numeral 6 denotes an outer cooling fin made of copper (Cu), for example, and an inner cooling fin 7 made of the same material is provided inside the cooling fin 6. These cooling fins are connected to a liquid nitrogen container 9 provided on the atmospheric side of the mirror body 8 via a flexible heat conduction member 10 and a heat conduction rod 11, and are kept at an extremely low temperature. Therefore, the particles can be effectively trapped.

[Problems to be solved by the invention] However, with the conventional device configured in this way, when the pole piece unit is replaced and the observation magnification is changed from a standard magnification of 800,000 times to an ultra-high magnification of 1.2 million times, The disadvantage of this method is that the inner cooling fin must be removed and the pole piece unit replaced each time, making the pole piece unit replacement work complicated.

The present invention was devised to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a sample contamination prevention device that facilitates the replacement work of the pole piece unit.

[Means for solving the problem] The structure of the present invention for solving the problem includes a pole piece unit in which a pair of magnetic pole pieces are integrally fixed, and a cylindrical shape arranged to surround the unit. a cooling fin; a cooling means for cooling the cooling fin from the atmosphere side via a heat transfer member; and a cooling trap integrally attached to the cooling fin, the cooling trap being configured to come into thermal contact with the cooling fin when the unit is inserted into the cooling fin.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention, and the same components as those of the conventional device shown in FIG. 2 are given the same numbers and their explanations will be omitted. In Figure 1, 12
is a spacer for connecting the upper magnetic pole piece 2a of the objective lens and the lower magnetic pole piece 2b of the objective lens, and an elastic force made of, for example, beryllium copper (BeCu) is applied to the spacer 12 via a heat insulating material 13. A U-shaped heat conductor (thermal conductor) 14 having
a, 14b are attached by heat insulating screws 15a, 15b. 16a and 16b are spacers 12
The cooling traps penetrate through the heat conductors 14a and 14b and are fixed to the heat conductors 14a and 14b by brazing or the like, and the tip of each cooling trap is fixed so as to be closest to the sample holding portion of the sample cylinder 4.

In the device configured in this way, the spacer 12
The heat conductors 14a and 14b are attached to the inside of the cooling fin 6 with an appropriate pressing force, and the cooling fin is connected to the pole piece unit 2A consisting of the upper magnetic pole piece 2a, the lower magnetic pole piece 2b, the spacer 12, the heat conductor, etc. 6 is formed so that it can be inserted and removed. With this configuration, when the pole piece unit 2A is inserted into the cooling fin 6, the cooling traps 16a, 16b are kept at an extremely low temperature via the heat conductors 14a, 14b and the cooling fin 6. Therefore, contamination-causing particles that fly close to the sample can be adsorbed and captured by the cooling trap, thereby preventing contamination of the sample.

Now, with an apparatus configured in this way, when changing the pole piece unit for observation by changing the observation magnification, for example, the pole piece unit can be simply inserted and removed from the cooling fin without having to remove the inner cooling fin each time. The pole piece unit can be easily replaced.

In this example, the present invention was described in detail as an example in which the present invention was applied to a top-entry type sample apparatus, but it can also be applied to a side-entry type sample apparatus, and in this case, it is called a cooling trap. The sample holding rods may be arranged on the same plane at right angles.

In addition, in the above embodiment, the elastic body was fixed to the spacer, but the cooling trap is fixed to the spacer while being thermally isolated, and the cooling trap is provided with an elastic body for thermal contact with the cooling fin. It is also possible to attach it.

Furthermore, a part of the outside of the cooling trap may be formed into a leaf spring shape instead of an elastic body.

[Effects of the invention] As detailed above, according to the invention, an apparatus is provided in which the pole piece unit can be replaced without removing the inner cooling fin in an apparatus for observing a sample image by replacing the pole piece unit. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional device. 1: Sample stage, 2A: Pole piece unit, 2a: Upper magnetic pole piece, 2b: Lower magnetic pole piece, 4: Sample cylinder, 5: Sample, 6: Cooling fin, 8: Mirror body, 9:
Liquid nitrogen container, 10: Heat conduction member, 11: Heat conduction rod, 12: Spacer, 13: Heat insulating material, 14a, 1
4b: Heat conductor, 15a, 15b: Heat insulating screw, 16a, 16b: Cooling trap.

Claims (1)

[Scope of utility model registration request] a pole piece unit in which a pair of magnetic pole pieces are integrally fixed; a cylindrical cooling fin disposed to surround the unit; a cooling means for cooling the cooling fin from the atmosphere side via a heat transfer member; A cooling trap is integrally attached to the unit so as to be located between the pair of magnetic pole pieces in a thermally isolated state, and when the unit is inserted into the cooling fin, a cooling trap is provided. 1. A sample contamination prevention device for an electron microscope, etc., characterized in that a cooling trap is configured to be in thermal contact with the cooling fin.