JPS6333141Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a thermocouple device for temperature measurement in ultra-high vacuum.

Conventionally, as shown in the first diagram, a pair of conductive wires b and b made of different metals such as platinum and platinum-rhodium are connected at their ends to form a measuring point a. , placed in an ultra-high vacuum vacuum chamber A, and insert the ceramic or other side wall d of the vacuum chamber A through each conductor b, b and each lead-out terminal c, c connected to its root side, and braze it to this. Types in which the lead-out terminals c and c are connected airtight with other wires are known;
This is a general formula consisting of a relatively large-diameter conductor made of a metal different from b, such as Cu, and in such a case, a different metal is involved in the closed circuit, so
This is accompanied by the disadvantage that measurement errors are likely to occur. That is, for example, when the temperature at measurement point a is around 1250°C, if the temperature difference is around 5°C, an error of about ±5°C will occur in the measured value.

Therefore, an attempt has been made to eliminate the lead-out terminals c and c made of dissimilar metals, extend the respective conductors b and b to the root side, insert them through the side wall d, and braze them to this e. However, in such a case, each conductor wire b, b has a relatively small diameter, for example, 0.3 mm, so if the wire is brazed at the insertion point e, it may break due to the temperature, or the alloy may break completely. This is accompanied by inconveniences such as bringing about the same results as the intervention of different metals.

The purpose of the present invention is to obtain a device which eliminates such disadvantages, and includes a pair of conductive wires 1 made of mutually different metals such as platinum and platinum-rhodium whose tips are joined to each other. 1 is placed in an ultra-high vacuum vacuum chamber A, and each conductive wire 1, 1 is inserted through the ceramic or other side wall 3 of the vacuum chamber A at each lead-out terminal 2, 2 connected to the root side thereof, and is also connected to the ceramic or other side wall 3 of the vacuum chamber A. In the type in which the lead-out terminals 2, 2 are airtightly connected by attachment 4 or the like, each lead-out terminal 2, 2 is constructed of a relatively large-diameter conducting wire made of the same metal as the respective conducting wires 1, 1.

FIG. 2 shows an example of this. When the conductor wires 1, 1 are made of platinum and platinum-rhodium thin wires each having a diameter of 0.3 mm, each lead-out terminal 2, 2 is made of platinum and platinum-rhodium each having a diameter of 1.0 mm. It should be a thick line with a diameter of mm. Thus, when these are brazed 4, each terminal 2 is only alloyed at its outer peripheral portion, and the center portion remains as it is, and each conductive wire 1 is connected to this, which prevents the intervention of dissimilar metals. It is something that cannot happen. Each terminal 2,2 is connected at its other end to a meter 6 via a respective conductor 5,5, for example a compensating conductor, so that the temperature of the junction 7 at its tip is known to it.

Each lead-out terminal 2, 2 is connected to a side wall 3 made of ceramic, for example.
The assembly is prepared in advance as an assembly as shown in FIG. 3 or 4, for example, by being inserted into the As shown in the figure, it is made to face into a transparent window 10 formed in advance on the side wall 3 of the vacuum chamber A, and is connected thereto by welding or other means.
In this case, each terminal 2 is connected to its tail end with each conductive wire 1 by spot welding, and in consideration of the case where it is removed once and reconnected, the terminal 2 is provided with a length margin. Let's make it somewhat long in advance, for example, to a length of 5 cm. That is, it is assumed that there is a margin for disconnecting the connection portion and reconnecting it.

In this way, according to the present invention, each lead-out terminal 2,
2 is a relatively large-diameter conductor wire made of the same metal as the conductor wires 1 and 1, and does not have the above-mentioned disadvantages, and has a simple configuration that allows high-precision measurement for ultra-high vacuum temperature measurement. It has the effect of

For example, growing crystals by molecular beam epitaxy requires extremely high-precision temperature control, and according to experiments by the inventor, the proposed device can be applied to this to achieve temperatures of, for example, 1250°C ± 0.1°C or 800°C to 800°C. 900℃±
It was confirmed that an accuracy of 0.2°C could be obtained.

[Brief explanation of the drawing]

Fig. 1 is a cut-away side view of a conventional example, Fig. 2 is a cut-away side view of an example of the proposed device, Fig. 3 is a cut-away side view of an example of an assembly of its main parts, and Fig. 4 is a front view thereof. be. 1, 1... Conductor wire, 2, 2... Output terminal, 3...
Side wall, 4...brazing, A...vacuum chamber.

Claims (1)

[Scope of utility model registration request] A pair of conductive wires 1, 1 made of mutually different metals such as platinum and platinum-rhodium whose tips are joined to each other.
are placed in ultra-high vacuum chamber A, and each conductor 1,
1 is inserted into the side wall 3 made of ceramic or other material of the vacuum chamber A at each lead-out terminal 2, 2 connected to the root side thereof, and is hermetically bonded thereto by brazing 4, in which each lead-out terminal 2 ,2
A thermocouple device characterized in that the conductive wires 1 and 1 are made of relatively large diameter conductive wires made of the same metal.