KR101167566B1 - Dry pumping system for transfer-holder of TEM equipped with a thermometer using infrared imaging system - Google Patents

Abstract

The present invention provides a vacuum for pretreatment of a cryo transfer holder comprising a sample stage, a sample support rod, an adiabatic double container portion, and an exhaust port equipped with an air valve, or a heat treatment test using a heating holder. A vacuum port equipped with a pump, a vacuum chamber and an air valve (where the vacuum port is connected to the vacuum chamber via a cylinder), a holder mount into which the holder is inserted-mounted, and a state of each part and controlling operation In a dry pumping system (DPS) including a control unit, the vacuum chamber internal space is divided into a first vacuum chamber and a second vacuum chamber by a gate valve, and the first vacuum chamber or the first vacuum chamber. And the second vacuum chamber is exhausted by the vacuum pump, and the vacuum port and the air valve are DPS mounted in the second vacuum chamber.
According to the present invention, the pretreatment work time of the cryo transfer holder used in the cryo experiment can be shortened, and the safety of the user can be improved through automation, and there is no need to turn off the main switch when mounting or detaching the holder. This can reduce the time spent.

Description

Dry pumping system for transfer-holder of TEM equipped with a thermometer using infrared imaging system}

The present invention relates to a vacuum pumping system (DPS) for pretreatment or pre-testing of a transfer holder (hereinafter simply referred to as a 'holder') for observing a sample in a transmission electron microscope. Relates to an improved DPS that increases safety through automation while significantly shortening the holder's pretreatment time or efficiently pre-testing the sample.

Transmission electron microscope (TEM) is a type of electron microscope that uses electron beams and electron lenses with similar properties instead of light sources and light source lenses.

Examples of observing samples in TEM include chemical fixation analysis, cryo analysis, and heating analysis.

The dual cryo assay describes the usual procedure to follow to observe a biological sample. First, the sample is suspended in a liquid (water, buffer, etc.), and then, pipette is placed on a predetermined pretreated support membrane (grid), and the water is removed with a filter paper or the like. The sample grid is immersed in an ethane solution cooled to the liquid nitrogen temperature level and rapidly cooled to prevent ice crystals from forming. The rapidly cooled sample grid is transferred from the workstation insulated vessel to the specimen cradle at the end of the cryo transfer holder (hereinafter referred to as the 'holder') (until this "sample preparation step"). ). Mount the holder on the TEM and obtain an image.

At this time, if the temperature of the holder (sample stage) changes or there is a temperature difference between the holder and the TEM main body, since there is a large adverse effect on the resolution, as shown in Figures 1a and 1b, the sample stage, the sample support rod and the insulating container portion Use a holder made of (dewar). 1A is a photograph of a holder mounted on a mounting table, and FIG. 1B is a cross-sectional view conceptually illustrating a cross-sectional structure of the holder.

In order to stably maintain the sample at a constant low temperature, the holder insulation container has a double container (thermic bottle) structure to block heat conduction from the outside to the inside, and an exhaust port 52 and an air valve 51 are installed outside. have. In order to use the holder, first, a vacuum pump is connected to the exhaust port of the insulated container part to maintain a high vacuum between the outer container 54 and the inner container (liquid nitrogen container) 53, and then the liquid nitrogen in the inner container of the insulated container part. It is to proceed to the "sample preparation step" containing (until the "holder pretreatment step").

2A and 2B are photographs and conceptual views of a holder and a DPS connected by a connecting tube, respectively. For reference, the sample stand and the sample support rod of the holder 50 are inserted and mounted inside the holder mount 10, and thus the drawings are omitted.

The order of use of the conventional DPS is usually as follows. First, the vacuum pump (normally using a diaphragm pump and / or a turbo molecular pump) is operated while the air valve 8 for the vacuum port of the DPS is locked. To be in vacuum (typically 10 ^-6 torr). ② Connect the exhaust port 52 of the holder inserted into the holder mount 10 and the vacuum port 7 of the DPS with the connecting tube, and the air port 8 for the vacuum port of the DPS and the air port for the exhaust port of the holder. Open 51. ③ It is maintained for 24 hours in a predetermined vacuum state (typically 10 ^-6 torr). ④ Follow the baking-out procedure if necessary. ⑤ Lock the air valve 51 for the exhaust port of the holder and the air valve 8 for the vacuum port of the DPS, cut off the pump power, and remove the holder (perform the sample preparation step).

However, the conventional DPS takes a long time for the pump to reach its maximum speed when the machine is running, and the pump has to be stopped even when the holder is mounted or removed. There is a disadvantage.

In addition, since the conventional DPS is operated manually, there is an inconvenience that a skilled expert in the work process should be waiting for the situation at all times.

On the other hand, the heating analysis method is a dynamic analysis method that analyzes while heating the sample in the transmission electron microscope, unlike the cryo analysis method. To this end, in the heating analysis method, unlike the cryo holder, a heating transfer holder installed with a heating device in the sample stage is used. According to the heating analysis method, the heating holder equipped with the sample is attached to the TEM and observed while applying heat. At this time, the most suitable heat treatment temperature or condition varies depending on the sample. Therefore, for efficient TEM analysis and in order to eliminate the possibility of large-scale accidents caused by scattering or explosion of a sample that may occur, it is necessary to conduct heat treatment test under the same conditions as the actual TEM in advance before heat analysis of a specific sample. Do.

In this heat treatment test, a heating holder on which a sample is seated is inserted into a holder holder for heating analysis, maintained in a vacuum in accordance with the above-described DPS usage sequence, and then heated (or heated) to a predetermined temperature. It is the process of observing the change of the sample with temperature. Therefore, this process requires accurate detection of the sample temperature.

In order to measure the temperature of the sample, the conventional sample holder is provided with a temperature sensor on a sample support rod far from the sample stage in which the sample is contained, as shown in FIG. According to this, the temperature and temperature distribution of the sample could not be confirmed.

In order to improve this disadvantage, the invention has been proposed that can directly detect the temperature of the sample stage by using a glass cylinder, a cartridge and a sensor (not shown; International Application No. PCT / KR2009 / 001628 filed by the present applicant) ).

However, according to the present invention, it is possible to reduce the thermal noise generated during the heat transfer process by directly measuring the temperature of the sample, but the overall heat distribution of the sample, the heat loss during the test because it senses the temperature of only the part in contact with the temperature sensor There was a drawback of not being able to detect part, thermal symmetry distribution, and temperature change during heating.

It is an object of the present invention to reduce the pretreatment time of the cryo holder, to improve the degree of vacuum inside the holder, to prevent loss of the sample, and to provide a new structure of the DPS that can increase the sample observation time in the TEM.

In addition, an object of the present invention is to provide a holder mount of a new structure that can be easily and accurately heat treatment test in the course of the experiment according to the heating analysis method.

It is also an object of the present invention to provide an improved DPS with increased user convenience and safety of equipment.

The present invention for achieving the above object, for the pre-treatment of cryo holders comprising a sample stand, a sample support rod, a heat insulating double container portion and an exhaust port equipped with an air valve for exhaust port, or for heat treatment test using a heating holder The apparatus includes a vacuum pump, a vacuum chamber, a vacuum port equipped with an air valve for the vacuum port (where the vacuum port is connected to the vacuum chamber via a cylinder), a holder mount into which the holder is inserted and mounted, and a state of each part. In the dry pumping system (DPS) comprising a control unit for sensing and controlling the operation, the vacuum chamber internal space is partitioned into a first vacuum chamber and a second vacuum chamber by a gate valve, the first vacuum chamber or the first vacuum chamber The vacuum chamber and the second vacuum chamber are exhausted by the vacuum pump, and the vacuum port and the air valve for the vacuum port are DPS mounted in the second vacuum chamber (see FIG. 3).

In the first vacuum chamber or only the first vacuum chamber and the second vacuum chamber of the DPS according to the present invention, a double vessel structure and a space between the outer vessel and the inner vessel are connected to the vacuum chamber, and the inner vessel It may be further equipped with an auxiliary cooling vessel, filled with liquid nitrogen.

In the present invention, the holder mounting table is provided with a mounting confirmation sensor for detecting whether the holder is completely mounted, the control unit is the vacuum pump is operated only when the input signal of the mounting completion from the mounting confirmation sensor You can also

In the present invention, a guide pin is installed on one side of the sample support rod of the holder, and at least two detecting the movement of the guide pin on both sides of the holder mount that is the copper wire of the guide pin during the insertion-reinsertion of the sample support rod. Pair movement sensor is installed, the control unit is preferably operated to operate the vacuum pump when receiving the sample support rod insertion signal from the movement sensor, and close the gate valve when receiving the sample support rod insertion signal.

In the present invention, the control unit may automatically close the vacuum port air valve in an abnormal situation.

In the present invention, the vacuum port is composed of a chamber connecting cylinder, a port connecting cylinder and a control cylinder that can adjust the connection length while sealingly connecting the chamber connecting cylinder and the port connecting cylinder.

In the present invention, when the heating holder is inserted-mounted, it is preferable to further form a cavity having at least one viewing window for internal observation, at the site where the sample holder of the heating holder is located. In this case, the viewing window may be made of an infrared ray transmitting material, and a thermal imaging camera may be mounted outside the viewing window.

As described above, according to the present invention, it is possible to shorten the pretreatment work time of the cryo transfer holder used in the cryo experiment, and it is not necessary to turn off the main switch when connecting the holder to the DPS, thereby reducing unnecessary consumption time.

In addition, the heat treatment test can be made simple and accurate, thereby increasing the speed and accuracy of the TEM observation by the heating analysis method.

In addition, by installing the auxiliary cooling vessel in the chamber to quickly adsorb the gas molecules generated during the baking-out process to improve the degree of vacuum.

In addition, if the vacuum down occurs in an abnormal state, the pre-vacuum work of the holder previously worked can be safely maintained.

In addition, by applying a vacuum port with a large cross-sectional area, it is possible to reduce the difference in the degree of vacuum between the DPS and the holder. It is also compatible with holders of different lengths and can be easily and simply installed.

1 is a photograph and diagram showing the structure of a cryo transfer holder.
Figure 2 is a photograph and conceptual diagram showing a state of use of the conventional dry pumping system and its use.
3 is an exemplary conceptual view showing a cross-sectional structure of a dry pumping system according to the present invention.
4 and 5 are conceptual views showing examples of the mounting confirmation sensor and the movement detection sensor, respectively.
6 is a conceptual diagram of a state in which a holder for pretreatment is mounted in the DPS according to the present invention.
7 is an exemplary structural diagram of a cylinder picture (FIG. 7A) and a length-adjustable cylinder according to the present invention for the vacuum port used in the DPS according to the present invention. FIG.
8 is an exemplary circuit diagram of a controller for controlling each part in the DPS according to the present invention.
9 is a flow chart showing the operation of the DPS according to the present invention.
10 is a diagram showing the degree of vacuum change of the holder vacuum space with time when the DPS according to the present invention is applied,
11 is a perspective view showing a partially broken holder mounting stand for a heating holder according to the present invention,
12 is a perspective view showing a part of the holder holder for the heating holder according to the present invention;
Figure 13 is a cross-sectional view showing a part of the heating holder according to the prior art with a built-in temperature sensor.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments. However, these drawings and embodiments are for illustrative purposes only, and thus the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

In the following, the pretreatment of the cryo holder will be mainly described as an example, but the heat treatment test procedure of the heating method may be described accordingly.

3 is a conceptual diagram showing an exemplary cross-sectional structure of the DPS 100 according to the present invention. As shown in FIG. 3, in the DPS 100 according to the present invention, a vacuum chamber is divided into a first vacuum chamber 2 and a second vacuum chamber 3 by a gate valve 4. In the drawing, for example, a structure in which the first and second vacuum chambers 2 and 3 are evacuated with one vacuum pump 1 is shown. However, as shown in FIG. 6, the first and second vacuum chambers 2 and 2 are vacuumed. The vacuum chambers 3 may be connected to the pumps, respectively, to increase the degree of evacuation and the degree of evacuation. In this case, the first vacuum chamber 2 is connected to a turbo molecular pump, and the second vacuum chamber 3 is connected to a diaphragm pump, and in the drawing, each pump is not shown separately. The vacuum pump 1 was indicated. In this case, the second vacuum chamber 3 is connected to the vacuum pump 1 by the air valve 9 for the second vacuum chamber. In addition, it will be obvious that various kinds of pumps may be applied depending on the degree of vacuum or pretreatment speed.

As shown, the chamber is divided by the gate valve 4 in the DPS 100 according to the present invention, and the first vacuum chamber 2 is always kept in a vacuum state. Therefore, since only the second vacuum chamber 3 needs to be made in a vacuum state during the pretreatment operation, the first vacuum chamber 2 and the second vacuum chamber 3 can shorten the time to reach the high vacuum state as a whole.

Conventional DPS has a disadvantage in that it takes a long time to turn on / off because the main switch must be turned off when connecting the holder (which means connecting the DPS and the holder with a hose or pipe through vacuum), but the vacuum according to the present invention By dividing the chamber into two parts by an airlock gate valve, unnecessary consumption time can be reduced.

In the present invention, in the first vacuum chamber, the space between the inner container (liquid nitrogen container), which has a double container structure to prevent heat transfer from the outside to the inside, is connected to the vacuum chamber and the liquid nitrogen is contained in the inner container. The auxiliary cooling vessel 5 to be filled may be further mounted. As a result, the conventional vacuum degree of the vacuum equipment than ^10E-helps to increase the degree of vacuum and the time to discharge the gas within the holder because it is possible to improve a degree of vacuum below ^1.

In addition, the apparatus according to the present invention includes a means for automatically detecting whether the holder is correctly mounted on the holder mount (mounting confirmation sensor, movement detection sensor) and a control unit for automatically driving the operation of the device according to the signal input therefrom Is installed, and the device can be automatically turned on and off according to the normal mounting and dismounting operation, and a vacuum down phenomenon occurs in an abnormal state (for example, power failure, air leakage to the device, or user error). Even so, it is possible to safely maintain the vacuum state of the holder which has been pre-worked to date.

The mounting confirmation sensor 11 confirms that the holder is fully mounted, and as a device for preventing operation and malfunction of the vacuum system of the DPS, for example, a limit switch can be applied. The limit switch is a kind of push switch, and the holder is fully inserted into the holder mount so that the switch is brought online while pressing the positioning projection of the limit switch, and when the holder is detached, the pressed projection is returned to offline. To be in a state (see FIG. 4).

The movement detecting sensor 12 is a device for locating the holder when the holder is long-detachable and confirms that the holder is inserted, and transmits the signal to the control unit so that the pre-vacuum work can be performed. It transmits a signal to the control unit to automatically close the gate valve, and functions to safely maintain the internal vacuum degree of the chamber. The movement detection sensor may apply photocouplers P1 and P2 as illustrated in FIGS. 5A and 5B. The photocoupler is configured such that two pairs face each other around the guide pin 57, and only one of the two pairs of photocouplers is shown in the drawing. As the guide pin 57 of the holder moves, it sequentially detects the movement of P1 → P2 (mounting process) or P2 → P1 (removing process) and transmits the signal value to the controller.

8 is an exemplary circuit diagram of a controller for controlling each part in the DPS according to the present invention, and FIG. 9 is a flowchart showing an operation process of the DPS according to the present invention.

In addition, in the present invention, the vacuum port may be configured to include a chamber connecting cylinder, a port connecting cylinder, and a control cylinder capable of variously adjusting the connecting length while sealingly connecting the chamber connecting cylinder and the port connecting cylinder.

7A shows a picture of a cylinder 6 having a diameter of Φ 14 mm × 300 mm in length for the cylinder 6 for the vacuum port 7 used in the DPS 100 according to the present invention. Accordingly, the conventional 3.2 mm diameter connecting tube 56 can be used with a length of 400 to 500 mm with a length of 100 to 150 mm, thereby greatly reducing the flow resistance of air for vacuum.

7b shows the structure of the adjustable cylinder 6 according to the present invention. As can be seen from the figure, the cylinder 6 includes a chamber connection cylinder 6-1 on the chamber side, a port connection cylinder 6-2 on the exhaust port 51 side, and the chamber connection cylinder 6-1. And an adjustment cylinder 6-3 capable of adjusting the connection length while sealingly connecting them between the port connection cylinders 6-2. Accordingly, even holders 50 having different lengths are compatible and conveniently mounted.

As described above, a holder holder for a heating holder may be used in the DPS for a heat treatment test for a heating analysis method. A heating means (not shown) such as a heating wire for heating the sample is installed in the sample holder of the heating holder, and the heating holder is inserted into the holder mounting unit 10 while the sample is seated on the sample holder. At this time, a cavity 21 having one or more viewing windows 22 is formed at the opposite end of the holder mount for observation of the heated sample. For convenience of explanation, this part is referred to as an internal observation unit 200. As shown in FIGS. 11 and 12, one side of the cavity 21 is connected to a connecting tube 56 to vacuum the inside of the cavity.

A thermal imaging camera 23 may be mounted outside the viewing window of the internal observation unit 200 so as to detect the temperature and temperature distribution of the entire sample. The thermal imaging camera 23 detects thermal energy radiated from a sample in the form of an infrared wavelength, which is a kind of electromagnetic waves, and images each color in a different color, and may select one of those already developed. In this case, the viewing window should be an infrared ray transmissive material.

< Example >

The DPS 100 according to the present invention having the structure shown in FIG. 6 and the cylinder 6 for the vacuum port 7 shown in FIG. 7A are applied to perform the pretreatment of the holder 50, and compared with the conventional DPS. .

When the DPS 100 according to the present invention is applied, the degree of vacuum change data of the holder 50 and the vacuum space 55 with time is shown in FIG. 10, and the vacuum chambers 2 and 3 and the vacuum space of the holder 50 during the pretreatment process ( 55) shows the degree of vacuum and the elapsed time leading to it in Table 1. In the figure, A represents a pre-vacuum process, B represents a baking-out process, and C represents a process after baking-out.

As a result, as shown in the table, it was confirmed that the baking-out process of step B can be shortened by 31 hours when using the DPS 100 according to the present invention as compared with the conventional DPS.

100.DPS
1. Vacuum pump 2. First vacuum chamber 3. Second vacuum chamber
4. Gate valve 5. Auxiliary cooling vessel
6. Cylinder
6-1. Chamber Connection Cylinder 6-2. Port connection cylinder
6-3. Adjustable cylinder
7. Vacuum port 8. Air valve for vacuum port
9. Air valve for 2nd vacuum chamber 10. Holder mount
11. Installation confirmation sensor 12. Movement detection sensor
50. Holder
51.Air valve 52.Exhaust port
53. Inner Container 54. Outer Container
55. Vacuum space 56. Connecting tube
57.Guide Pin
200. Internal Observation Department
21.cavity 22: sight glass
23: thermal imaging camera

Claims (8)

Vacuum pump, vacuum chamber as a device for pretreatment of cryo transfer holders including sample holder, sample support rod, double insulation container and exhaust port equipped with air valve, or heat treatment test using heating holder. A vacuum port equipped with an air valve for the vacuum port (where the vacuum port is connected to the vacuum chamber via a cylinder), a holder mount to which the cryo transfer holder or heating holder is inserted-mounted, and detects a state of each part In the vacuum pump system (Dry pumping system) including a control unit for controlling the operation,
The inner space of the vacuum chamber is divided into a first vacuum chamber and a second vacuum chamber by a gate valve, and the first vacuum chamber or the first vacuum chamber and the second vacuum chamber are exhausted by the vacuum pump, and the vacuum port And a vacuum port air valve is mounted to the second vacuum chamber.
The method of claim 1,
The first vacuum chamber or the first vacuum chamber and the second vacuum chamber
A double container structure, wherein the space between the outer container and the inner container is connected to the vacuum chamber, the inner container is filled with liquid nitrogen, DPS, characterized in that additionally equipped with an auxiliary cooling vessel.
The method according to claim 1 or 2,
The holder mounting base is equipped with a mounting confirmation sensor for detecting whether the cryo transfer holder or heating holder is completely mounted,
The control unit operates the vacuum pump only when receiving a mounting completion signal from the mounting confirmation sensor.
The method according to claim 1 or 2,
A guide pin is installed at one side of the sample support rod of the cryo transfer holder or the heating holder,
At least two pairs of movement detecting sensors for detecting movement of the guide pins are installed at both sides of the holder mount which is the copper wire of the guide pins during the insertion-reinsertion of the sample support rod.
The control unit operates the vacuum pump when receiving the sample support rod insertion signal from the movement sensor, and closes the gate valve when the sample support rod insertion signal is input.
The method according to claim 1 or 2,
The control unit DPS, characterized in that for automatically closing the air valve for the vacuum port in an abnormal situation.
The method according to claim 1 or 2,
The vacuum port,
DPS characterized in that consisting of a chamber connecting cylinder, a port connecting cylinder and a control cylinder that can adjust the connection length while sealingly connecting the chamber connecting cylinder and the port connecting cylinder.
The method according to claim 1 or 2,
The holder mount,
When the heating holder is inserted-mounted DPS, characterized in that it comprises a cavity having at least one viewing window for the internal observation, the site where the sample holder of the heating holder is located.
The method of claim 7, wherein
The see-through window is an infrared ray transmissive material, characterized in that the thermal imaging camera is mounted to the outside of the see-through window.

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