JPS6328521Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cooler for cooling an energy dispersive semiconductor detector (hereinafter abbreviated as EDS) used in an electron microscope or the like.

Some electron microscopes and X-ray microanalyzers use EDS. EDS like this
Since the sample must be cooled to an extremely low temperature before use, a cooler is usually installed in the sample chamber of an electron microscope using EDS. This cooler is equipped with a container for containing a cooling liquid such as liquid nitrogen, and a conduction rod for conducting heat from the object to be cooled (i.e., EDS in this case) to the liquid nitrogen in the container.
The mounting is carried out by inserting the end of the heat conducting rod into the sample chamber. By the way, a coolant such as liquid nitrogen vaporizes as it removes heat, and the gas generated thereby exits the container, but as a result of this vaporization, bubbles are generated in the coolant tank, rising, and Disappearances occur frequently. All of these involve the movement of coolant, but in the past, the container was open to atmospheric pressure, so the bubbles generated were quite large.
Therefore, since the amount of movement of the coolant is large, large vibrations are generated, and these vibrations are transmitted to the sample chamber via the heat conduction rod, which is an obstacle to performing high-resolution observation using an electron microscope or the like.

The purpose of this project is to solve these conventional drawbacks and provide a cooler that enables high-resolution observation with electron microscopes, etc. by suppressing the vibrations mentioned above. and a conduction means for transmitting heat from the object to be cooled to a cooling liquid in the container, and is installed in a sample chamber or vacuum exhaust pipe of an electron microscope, etc., in which the inside of the container is brought to a predetermined pressure. a safety valve for releasing internal gas when approaching the container; a valve body provided separately from the safety valve for changing the amount of opening of a discharge port for discharging vaporized cooling liquid to the outside of the container; It is characterized by a means for generating mechanical movement in accordance with the pressure within the container, and a means for converting the mechanical movement into the amount of opening of the valve body. Examples will be explained in detail.

In the drawing, 1 is a container containing liquid nitrogen 2, and a heat conduction rod 3 is attached to the bottom of the container to remove heat from the EDS. A port 4 for filling liquid nitrogen is provided at the top of the container 1, and this port 4 is sealed with a lid 5. 6 is a discharge port for discharging vaporized liquid nitrogen, and the opening amount of this discharge port 6 is determined by a valve body 8 supported via an arm 7 that moves in the direction of arrow K.
It is now possible to change depending on the Reference numeral 9 denotes a bellows for detecting the pressure inside the container by utilizing the fact that the amount of compression changes depending on the pressure inside the container, and one end of the shaft 10 is integrally attached to the bottom surface of the bellows 9. There is. The other end of the shaft 10 is engaged with the arm 7 by a pin or the like. Reference numeral 11 denotes a support for the arm 7, and the arm 7 swings around a mounting shaft 12 of the support 11. Reference numeral 13 denotes a valve body of a safety valve, and this valve body 13 rises against the force of a spring 15 to release internal gas when the pressure approaches high enough to damage the container 1.

In such a configuration, when the pressure inside the container 1 detected by the bellows 9 increases, the shaft 10 moves in the direction of the arrow M, and this movement is converted into a downward movement of the valve body 8 via the arm 7. and outlet 6
When the pressure inside the container 1 decreases, the shaft 10 moves in the opposite direction to the arrow M, and the valve body 8 is moved so as to decrease the discharge amount from the discharge port 6. let Therefore, by appropriately setting the lever ratio of the arm 7, the initial position of the valve body 8, etc., the pressure inside the container 1 can be reduced by, for example, 2 to 3 seconds during the process in which the cooling liquid is vaporized and discharged from the discharge port 6.
It is possible to maintain a substantially constant pressure higher than atmospheric pressure, which is about atmospheric pressure. As a result, the volume of bubbles generated in the coolant can be kept small at all times.
Since vibrations caused by movement, disappearance, etc. can be suppressed to a smaller level, more stable high-resolution observation using an electron microscope or the like is possible.

Incidentally, the present invention can be similarly implemented for a cooler attached to a vacuum exhaust pipe.

[Brief explanation of the drawing]

The drawings are for showing one embodiment of the present invention. 1... Container, 2... Liquid nitrogen, 3... Heat conduction rod, 4... Mouth, 5... Lid, 6... Outlet, 7...
Arm, 8... Valve body, 9... Bellows, 10...
Axis, 11... Support, 12... Mounting axis, 13...
...valve body.

Claims (1)

[Scope of utility model registration request] It is equipped with a container for containing a cooling liquid such as liquid nitrogen, and a conduction means for conducting heat from the object to be cooled to the cooling liquid in the container, and is installed in a sample chamber of an electron microscope or the like or in a vacuum exhaust pipe. In the cooler,
a safety valve for releasing internal gas when the inside of the container approaches a predetermined pressure; and a safety valve provided separately from the safety valve to change the opening amount of an outlet for discharging the vaporized cooler to the outside of the container. 1. A cooler for an electron microscope, etc., comprising a valve body for the purpose of opening the valve body, a means for generating mechanical movement according to the pressure within the container, and a means for converting the mechanical movement into an opening amount of the valve body.