JPH067076U - Sample holder guide mechanism in a cryostat for a vibrating sample magnetometer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a guide mechanism for a sample holder capable of ensuring high detection accuracy in a cryostat used for a vibrating sample magnetometer. I will provide a. [Configuration] A spacer ring (3) made of non-magnetic resin is attached to the inner peripheral surface of the guide tube (4) in the cryostat for the vibrating sample magnetometer.
4) was attached, and a sample holder insertion hole (35) for linearly moving the sample holder (8) was provided at the center of the spacer ring (34).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a retractable guide mechanism for a sample holder in a cryostat used in a vibrating sample magnetometer for measuring the magnetization characteristics in a region from extremely low temperature to room temperature.

[0002]

[Prior art]

 As shown in FIG. 7, a cryostat used for a conventional vibrating sample magnetometer accommodates an annular liquid nitrogen tank (51) inside a casing (50) and also inside the internal space of this liquid nitrogen tank (51). The liquid helium tank (52) is placed in the liquid helium tank (52), and the vibrating rod guide cylinder (54) formed by the double quartz glass tube (53) is inserted into the inside of the liquid helium tank (52). ) Is vacuum-insulated between the casing (50) and the liquid nitrogen tank (51) and between the liquid nitrogen tank (51) and the liquid helium tank (52), and the inner quartz glass tube (5 3 ), The vibration rod (55) is arranged so that it can move forward and backward, and the sample mounting holder (56) is formed at the protruding tip of the vibration rod (55), and the vibration rod (55) is vibrated. A device is connected and configured to vibrate along the axis, and a vacuum insulation state and a heat transfer gas filled transfer are provided between the inner and outer quartz glass tubes (53, 53). The inner quartz glass tube (53) was formed so as to be filled with a heat transfer gas while being switched to the heat state.

[0003]

[Problems to be solved by the device]

 In this type of cryostat, a slight change in magnetic force is detected by a detection unit arranged near the tip of the cryostat, so an electromagnetic member such as a motor that may disturb magnetic flux is used. The vibrating device is placed at a location away from the detector. For this reason, the sample rod (55) becomes long, and the sample rod (55) sometimes sways in the inner quartz glass tube (53) in a direction orthogonal to the axial center when the sample rod (55) reciprocates. As a result, in the conventional cryostat, there is a problem that the detection result in the detection unit is disturbed due to the shake in the direction orthogonal to the axis, and it is difficult to improve the detection accuracy. The present invention has been made paying attention to such points, and an object thereof is to provide a guide mechanism for a sample holder in a cryostat for a vibrating sample magnetometer, which can ensure high detection accuracy.

[0004]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention is to mount a spacer ring made of non-magnetic resin on the inner peripheral surface of a guide cylinder in a vibrating sample magnetometer cryostat, and to install a sample ring at the center of this spacer ring. The sample holder insertion hole that guides the holder so that it can move linearly is provided through.

[0005]

[Action]

 According to the present invention, a spacer ring made of non-magnetic resin is attached to the inner peripheral surface of the guide cylinder in the cryostat for a vibrating sample magnetometer, and a sample holder that guides the sample holder linearly in the center of this spacer ring. Since the insertion hole is provided through, the shake in the direction orthogonal to the axis of the sample holder can be suppressed, and the sample holder can be linearly moved in and out.Therefore, the change in magnetic flux caused by the shake can be suppressed. Disturbance can be prevented and high detection accuracy can be maintained.

[0006]

【Example】

 1 to 6 show an embodiment of the present invention, FIG. 1 is an enlarged view of a guide portion of a sample rod, FIG. 2 is a schematic configuration diagram of a cryostat, FIG. 3 is a vertical sectional view of a cryostat, and FIG. FIG. In this cryostat, a cold head (3) of an extremely low temperature refrigerator (2) and a metal guide tube (4) are arranged so as to protrude from the upper wall of a casing (1) formed in an airtight structure, and the cold head ( 3) and the compressor unit (5) of the cryogenic refrigerator (2) are connected by a pair of flexible tubes (6) and an electric cord (7), and the sample holder (8) is placed inside the guide tube (4). ) Is inserted so that it can be vertically vibrated, and the upper end of the sample holder (8) is interlockingly connected to the vibrating device (9) in a removable state.

The metal guide tube (4) that is inserted into the casing (1) has a bottomed cylinder (10) made of a non-magnetic material having good thermal conductivity such as copper and a heat defect such as stainless steel. It is formed by brazing and joining the tubular body (11) made of a conductive non-magnetic material, the bottomed tubular body (10) is located in the plunge depth, and the joint part is located in the casing (1). It is arranged to Further, the cold head (3) has two cold heat generating parts (12), and the pipe body (11) of the guide cylinder (4) is transferred to the tropical zone at the first stage cold heat generating part (high temperature side) (12a). In addition to being thermally connected by (13), the bottomed cylindrical body (10) of the guide cylinder (4) is thermally connected by the heat transfer zone (13) to the second stage cold heat generation part (low temperature side) (12b). Connected to. The heat transfer zone (13) connecting the cold heat generating part of the cold head (3) and the guide cylinder (4) is formed by weaving a thin copper wire into a strip shape, which has flexibility and is high. It is formed to have thermal conductivity.

The guide cylinder (4) has a tubular body (11) projecting above the casing (1), and has a heat transfer medium supply / discharge block (15) at its upper end through a passage opening / closing valve (14). ) Is placed. The heat transfer medium supply / exhaust block (15) communicates with an exhaust port (17) communicating with a vacuum pump (16) and a helium gas cylinder (18) storing helium gas as a heat transfer medium. An air port (19) and a supply / discharge port (21) that communicates with the air blower as a pressure fluctuation absorbing tool (20) in the space inside the guide cylinder are formed.

A sample holder (8), the upper end of which is detachably linked to a vibrating device (9), penetrates the ceiling wall of the heat transfer medium supply / discharge block (15) into the guide tube (4). The sample holder (22) is formed at the lower end of the sample holder (8). Also, a thermometer for measurement (23) formed of a gold-iron vs. normal silver thermocouple is arranged near the sample holder (22) of the sample holder (8). (23) is connected to the temperature display device (24) arranged outside the casing (1).

A copper pipe (25) having a liquefied gas passage formed inside is wound around the outer periphery of the guide pipe (4), and one end of the copper pipe (25) is placed outside the casing (1). It is connected to the liquefied gas storage container (26) arranged, and the other end is connected to the vacuum pump (16) via the warmer (27). In addition, the temperature adjustment heater (28) is located at the place where the influence of the magnetic field is the smallest when set in the vibrating sample magnetometer near the joint of the bottomed cylindrical body (10) located on the rush tip side of the joint. In addition to the temperature adjustment heater (28), a temperature adjustment thermometer (29) formed of a gold-iron vs. chromel thermocouple is placed near the temperature adjustment heater (28). Each is connected to a temperature control device (30) arranged outside the casing (1).

The inside of the casing (1) is connected to a vacuum pump (16) through a vacuuming line (32) connected to a vacuum port (31) formed on a peripheral side wall of the casing (1). The casing (1) is formed so as to be vacuum-insulated. Reference numeral (33) in the figure is a flow path opening / closing valve arranged in the vacuum line (32).

Inside the guide cylinder (4), a spacer ring (34) formed of a synthetic resin having a non-magnetic property such as fluorinated ethylene resin, polyimide resin or phenol resin is attached. As shown in FIG. 5, the spacer ring (34) is fixedly mounted on the inner surface of the guide tube (4) at a position where the influence of the magnetic field is least, and the insertion hole (35) of the sample holder (8) is provided at the center thereof. ) Is transparently provided, and the ventilation hole (36) is formed in an arc shape so as to surround the insertion hole (35).

FIG. 6 shows a modified example of the spacer ring (34), in which the entire shape of the spacer ring (34) made of non-magnetic synthetic resin is changed to a triangular prism shape inscribed in the guide tube (4). The sample holder (8) is provided with an insertion hole (35) in the center thereof, and an air passage is formed between the outer peripheral wall (37) of the spacer ring (34) and the inner peripheral wall of the guide tube (4). It was formed.

In the cryostat thus formed, the guide cylinder (4) accommodating the sample holder (8) so as to be able to move forward and backward is directly cooled by the cryogenic refrigerator (2), and the guide cylinder (4) is also cooled. Since the heat transfer medium such as helium gas is sealed inside, the cold heat generated in the cryogenic refrigerator (2) can be efficiently transferred to the sample. Moreover, since the guide tube (8) has a copper tube (25) having a liquefied gas passage formed inside the guide tube (8), and a temperature adjusting heater (28) disposed on the outer surface of the guide tube (8). It can be cooled to temperatures from 0.2K to room temperature.

Further, in the cryostat of the present embodiment, the guide cylinder (4) is made of a material having good thermal conductivity such as copper, and the bottomed cylinder (10) and the stainless steel continuous with the bottomed cylinder (10). By forming a pipe (11) made of a low thermal conductivity material such as steel and exposing the pipe (11) made of this low thermal conductivity material to the outside of the casing (1), the heat inside the cryostat is reduced. The invasion is suppressed and the temperature change in the detection part is eliminated.

Furthermore, since the heat transfer medium supply / discharge block (15) is connected to the upper end of the tube body (11) of the guide cylinder (4) through the passage opening / closing valve (14), when exchanging samples, etc. When the sample holder (8) is pulled out from the guide tube (4), the passage opening / closing valve (14) is closed to form a closed space inside the guide tube (4). As a result, the sample can be exchanged while the cryostat is kept at a low temperature.

Moreover, since the heat transfer medium in the guide tube (4) does not escape to the outside during the sample exchange, the volume inside the heat transfer medium supply / discharge block (15) is evacuated to fill the heat transfer medium. Since the filling can be performed, the wasteful consumption of the heat transfer medium can be reduced.

Moreover, since the pressure fluctuation buffering device (20) such as a balloon is connected to the heat transfer medium supply / discharge block (15) in communication, the sample holder (8) is vibrated during measurement. The pressure fluctuation in the guide cylinder (4) due to the movement of the guide tube (4) can be buffered by the pressure fluctuation buffer (20) so that the inside of the guide cylinder (4) can be maintained at a constant pressure. As a result, it becomes possible to suppress temperature variations due to pressure fluctuations and perform stable measurements.

[0019]

[Effect of device]

 The present invention is a cryostat for a vibrating sample magnetometer, in which a spacer ring made of non-magnetic resin is mounted on the inner peripheral surface of a guide cylinder, and a sample holder is provided in the center of the spacer ring for linear movement. Since the holder insertion hole is transparently provided, it is possible to suppress the shake in the direction orthogonal to the axis of the sample holder and linearly move the sample holder back and forth, resulting in the shake of the sample holder. It is possible to prevent disturbance of the magnetic flux change and maintain high detection accuracy.

[Brief description of drawings]

FIG. 1 is a main part extraction view showing a sample holder guide mechanism.

FIG. 2 is a schematic configuration diagram of a cryostat used in a vibrating sample magnetometer.

FIG. 3 is an enlarged view of a main part of a cryostat used in a vibrating sample magnetometer.

FIG. 4 is a vertical cross-sectional view of a cryostat used for a vibrating sample magnetometer.

FIG. 5 is a perspective view showing a spacer ring taken out.

FIG. 6 is a take-out perspective view showing a modified example of the spacer ring.

FIG. 7 is a longitudinal sectional view showing a conventional example of a cryostat used for a vibrating sample magnetometer.

[Explanation of symbols]

1 ... Casing, 4 ... Guide tube, 8 ... Sample holder, 9 ... Excitation device, 34 ... Spacer ring, 35 ... Sample holder insertion hole.

Claims (1)

[Scope of utility model registration request] 1. A metal-made guide tube (4) is arranged inside a casing (1) formed in an airtight structure so as to protrude from the outside of the casing (1), and a sample holder is provided inside this guide tube (4).
A cryostat for use in a vibrating sample magnetometer, in which (8) is mounted so that it can be moved back and forth, and the projecting end of the sample holder (8) projecting from the guide tube (4) is interlockingly connected to a vibrating device (9). And a spacer ring made of non-magnetic resin on the inner peripheral surface of the guide tube (4).
For a vibrating sample magnetometer, which is equipped with (34) and has a sample holder insertion hole (35) formed in the center of the spacer ring (34) for guiding the sample holder (8) in a linearly movable manner. Sample holder guide mechanism for cryostat.