JPH074766Y2 - Liquid gas evaporation prevention device for EDS detector cooling - Google Patents

Description

[Detailed description of the device]

[0001]

The present invention relates to an energy dispersive X-ray detector (E) for providing an electron microscope with an elemental analysis function.
The present invention relates to a device for preventing evaporation of liquefied gas in a low temperature generator used for cooling a DS detector) with liquefied gas.

[0002]

2. Description of the Related Art Generally, in an EDS detector, the EDS detector is cooled with a liquefied gas such as liquid nitrogen in order to improve its measurement accuracy. However, conventionally, the bottom of a storage container for storing the liquefied gas is used. The cold finger is taken out from the wall, and the EDS detector is attached to this cold finger.
The liquefied gas is used to keep the EDS detector in an ultra-low temperature state. In this case, the EDS detector has a restriction that it must maintain the cooling temperature once cooled. On the other hand, the electron microscope main body is supported on the floor via a vibration absorber such as a spring, and the liquefied gas storage container is fixed to the electron microscope main body so that the EDS detector can be retract-moved during the detection operation.

Since the liquefied gas used for cooling the EDS detector is scattered outside the container by evaporation,
In order to maintain the cooling temperature within a certain range for a long time, the scattered gas content had to be supplemented, and therefore the operator had to frequently replenish the liquefied gas storage container with the liquefied gas. However, in the electron microscope using the EDS detector, the height from the floor surface where the liquefied gas storage container for cooling the EDS detector is arranged is regulated in relation to the irradiation axis. In the prior art, since the liquefied gas replenishment port that is opened at the upper part of the liquefied gas storage container is opened at a high position of, for example, 1.5 m from the floor surface, a replenishment container such as this Dewar bottle is used. There is a problem that the work of replenishing the liquefied gas storage container with the liquefied gas is troublesome.

Therefore, the applicant first installed a cold head of a cryogenic refrigerator at the upper end opening of the liquefied gas storage container and condensed the gas vaporized in the liquefied gas storage container in the cryogenic refrigerator. By doing so, it has been proposed to reduce the consumption of liquefied gas (Japanese Patent Laid-Open No. 27997/1990).
No. 7).

[0005]

However, in the conventional one in which the cold head of this cryogenic refrigerator is attached to the upper end opening of the liquefied gas storage container, the cold head of the cryogenic refrigerator is mounted on the floor of the electron microscope main body. Since it was supported separately from the stand, the cold head and the electron microscope main body become different vibration systems, and external force acts on the electron microscope main body and the electron microscope main body swings and swings. When the vibration occurs, the cold head and the liquefied gas storage container move relative to each other, and there is a problem in that the connecting portion between the two becomes unreasonable. In particular, this problem remarkably appears when the retract rail that movably supports the liquefied gas storage container is arranged in an inclined manner. The present invention has been made paying attention to such a point, and the cold head can be supported without moving relative to the liquefied gas storage container, and the liquefied gas evaporation operation that can omit the refueling operation of the liquefied gas for a long period of time can be omitted. The purpose is to provide a protection device.

[0006]

In order to achieve the above object, the present invention is to fix a reinforcement support of a retract rail to a main body of an electron microscope, and to support a retractable liquefied gas storage container on the retract rail. Then, the cold head of the cryogenic refrigerator is attached to the upper end opening of the liquefied gas storage container through the support plate with the cold end portion thereof protruding into the liquefied gas storage container, and the liquefied gas storage container and the support plate are attached. The cold head is fixed to the liquefied gas storage container by connecting with a connecting fixture.

[0007]

In the present invention, the reinforcement support of the retract rail is fixed to the main body of the electron microscope, and the liquefied gas storage container is movably supported by the retract rail.
Attach the cold head of the cryogenic refrigerator to the upper end opening of the liquefied gas storage container via the support plate with the cold end part protruding into the liquefied gas storage container, and fix the liquefied gas storage container and the support plate together. Since the cold head is fixed to the liquefied gas storage container by connecting it with a tool, the cold head of the cryogenic refrigerator is configured integrally with the liquefied gas storage container that is relatively fixed to the electron microscope main body. Since the cold head of the cryogenic refrigerator vibrates together with the liquefied gas storage container, it is possible to prevent relative displacement between the liquefied gas storage container and the cold head due to vibration, so the cold head has a simple structure. In addition to being surely supported by the support structure, the inside of the liquefied gas storage container is operated by the action of the cryogenic refrigerator in which the cold end is thrust into the liquefied gas storage container. Since will be condensed vaporized gas, it is possible to suppress the scattering consumption of liquefied gas, becomes possible to greatly prolong the replenishment cycle of liquefied gas to the liquefied gas storage vessel.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of the present invention, FIG. 1 is a schematic structural view showing a state of mounting a liquefied gas storage container on an electron microscope, and FIG. 2 is a drawing out a main part of a liquefied gas container supporting device.

In the figure, reference numeral (1) is an electron microscope in which the main body portion (2) is supported on the floor through a vibration absorber such as a spring, and (3) is an EDS cooling in which cold fingers are led out from the bottom wall. This is a liquefied gas storage container for use, and the liquefied gas storage container (3) is supported by the main body portion (2) of the electron microscope (1) in a relatively movable state. That is, the retract rail (5) is fixed to the retract rail reinforcement support (4) protruding from the main body portion (2) of the electron microscope (1), and the traveling platform (6) is screwed to the retract rail (5). A liquefied gas storage container is placed on the traveling table (6) so that it can be moved along the retract rail (5) by a moving mechanism such as a device.
Liquefied gas storage container (3) by mounting and fixing (3)
Is configured to be retractable with respect to the main body portion (2) of the electron microscope (1).

Reference numeral (7) is a support plate for disposing the cold head (9) of the cryogenic refrigerator at the upper end opening (8) of the liquefied gas storage container (3). Is the cold head (9) of the cryogenic refrigerator and its cold end part (10)
Is fixed in a state of protruding downward. The support plate (7) is placed on the liquefied gas storage container while the cold end portion (10) is projected into the liquefied gas storage container (3).
It is attached to the upper end opening (8) of (3), and the support plate (7) and the liquefied gas storage container (3) are fixed by a container connecting fixture (11). The connecting fixture (11) includes a strip plate ring (12) wound around the body of the liquefied gas storage container (3) and the strip plate ring (12).
Coil springs (13) for connecting the support plate (7) with the support plate (7)
It consists of and. Strip ring (12) is a liquefied gas storage container
The coil spring (13) is fitted to the lower part of the weld bead (14) formed in the body of the body (3) in the circumferential direction, and the support plate (7) is attached to the liquefied gas storage container (3) side. It acts to pull to.

Therefore, the strip plate ring (12) is received by the lower peripheral edge of the welding bead (14) by the elastic force of the coil spring (13), and the support plate (7) is pressed against the liquefied gas storage container (3). Therefore, the support plate (7) is a liquefied gas storage container.
It will be crimped and fixed in the opening (8) of (3). In addition,
The elastic force of this coil spring (13) causes the support frame (7) to move to the liquefied gas storage container (3) even when the internal pressure in the liquefied gas storage container (3) rises by stopping the operation of the cryogenic refrigerator. The size is set so that it can be pressed with a force greater than a predetermined contact force. Reference numeral (15) in the figure is a liquefied gas storage container (3)
A liquid level gauge for displaying the amount of liquefied gas inside, (16) is a pressure gauge for displaying the pressure in the liquefied gas storage container (3), and (17) is a safety valve.

In the above embodiment, the band plate ring (12) and the supporting frame are
Coil spring (13) is placed between (7) and support plate
Although (7) is pressed against the liquefied gas storage container (3), a rubber belt may be used instead of this coil spring (13), or a support plate (7) may be used by using a turnbuckle. ) May be pressed against the strip ring (12).

FIG. 3 shows a support plate (7) with a liquefied gas storage container (3).
2 shows another structure for supporting the support plate (7) so as to be detachably fixed to the liquefied gas storage container (3) through a vibration isolator (18) such as a vibration isolation bellows, and a connecting fixture. A pair of upper and lower strip plate rings (12) in which (11) are arranged in the body of the liquefied gas storage container (2) with a welding bead (14) sandwiched between them, and this strip plate ring (1
2) and the support plate (7) are connected by a connecting frame (19) made of damping material.

When the supporting plate (7) is connected in this manner, the supporting plate (7) and the pair of upper and lower band plate rings (12) are fixed via the connecting frame (19) without any relative displacement. Liquefied gas storage container along with the operation of the cryogenic refrigerator.
Even if the pressure in the (3) becomes negative and a force in the direction of contracting the vibration isolator (18) acts between the support plate (7) and the liquefied gas storage container (3), a pair of upper and lower Upper ring of strip ring (12)
Welding bead (12a) formed in liquefied gas container (2)
Since (14) is received, the moving force for contracting between the support plate (7) and the liquefied gas storage container (3) is suppressed. In addition, the pressure inside the liquefied gas storage container (3) becomes positive due to the operation stop of the cryogenic refrigerator, etc.
Even if a force in the direction of extending the vibration isolator (18) acts between the liquefied gas storage container (3) and the liquefied gas storage container (3), a pair of upper and lower strip plate rings (1
Since the lower ring (12b) of 2) receives the welding bead (14) formed in the liquefied gas storage container (3), the support plate (7) and the liquefied gas storage container (3) The movement force that tries to extend the space is suppressed.

In the cryogenic refrigerator of each of the above-mentioned embodiments, the vibration accompanying the operation of the cryogenic refrigerator is not transmitted to the EDS detector and the electron microscope (1) during the operation of the electron microscope (1). The operation mode is controlled so that the cryogenic refrigerator is operated when the electron microscope (1) is not operated and the vaporized gas can be condensed.

[0016]

According to the present invention, the reinforcement support of the retract rail is fixed to the main body of the electron microscope, the liquefied gas storage container is movably supported by the retract rail, and the cold head of the cryogenic refrigerator is used as the cold head. The cold head is liquefied by attaching it to the upper end opening of the liquefied gas storage container via the support plate with the end part protruding into the liquefied gas storage container, and connecting the liquefied gas storage container and the support plate with the connecting fixture. Since it is fixed to the gas storage container, the cold head of the cryogenic refrigerator is configured integrally with the liquefied gas storage container that is fixed relatively to the electron microscope body, and the cold head of the cryogenic refrigerator is liquefied. It will vibrate integrally with the gas storage container. Therefore,
Since the relative displacement between the liquefied gas storage container and the cold head due to vibration can be prevented, the cold head can be reliably supported by the support structure with a simple structure, and the cold end can be projected into the liquefied gas storage container. Due to the action of the cryogenic refrigerator that is used, the gas vaporized in the liquefied gas storage container is condensed and liquefied, so the scattered consumption of liquefied gas can be suppressed, and the liquefied gas replenishment cycle to the liquefied gas storage container can be reduced. It will be possible to significantly lengthen the period.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a state of attachment to an electron microscope.

FIG. 2 is a drawing out of an essential part of a liquefied gas container support device.

FIG. 3 is a main part extraction view showing another embodiment of the liquefied gas container support device.

[Explanation of symbols]

1 ... Electron microscope, 2 ... Main body of electron microscope, 3 ... Liquefied gas storage container, 4 ... Retract rail reinforcement support, 5 ... Retract rail,
7 ... Support plate, 8 ... Upper end opening of liquefied gas container, 9 ... Cold head, 10 ... Cold end part, 11 ... Connection fixing tool.

Front page continuation (72) Inventor Etsuji Kawaguchi 1095 Katsube-cho, Moriyama City, Shiga Iwatani Planech Co., Ltd., Shiga Plant (56) Reference JP-A-2-279977 (JP, A) JP-A-63-261146 (JP) , A)

Claims (1)

[Scope of utility model registration request] 1. A body part (2) of an electron microscope (1) supports a liquefied gas storage container (3) for cooling an EDS detector via a retract rail (5), and the liquefied gas storage container (3) is In the liquefied gas evaporation prevention device for cooling the EDS detector, which is equipped with a cold head (9) of a cryogenic refrigerator in the upper end opening (8), a retract rail (5) is attached to the body part (2) of the electron microscope (1). The reinforcement support (4) is fixed, and the liquefied gas storage container (3) is supported on the retract rail (5) so that the liquefied gas storage container (3) can be retractably moved, and the cold head (9) of the cryogenic refrigerator is connected to its cold end portion (10). The liquefied gas storage container (3) and the supporting plate are attached to the upper end opening (8) of the liquefied gas storage container (3) through the support plate (7) while protruding into the liquefied gas storage container (3).
A liquefied gas evaporation preventing device for cooling an EDS detector, characterized in that a cold head (9) is fixed to a liquefied gas storage container (3) by connecting it with a connecting fixture (11).