JPS5836047Y2 - Temperature sensor for cryogenic temperatures - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a temperature sensor suitable for measurement in an extremely low temperature region.

The measurement limit on the low temperature side of conventional temperature sensors using platinum resistance wire materials, etc. is IOK as shown in sensitivity characteristic curve 1 in Figure 1.
Below that, there was no change in resistance and measurement was impossible.

However, in recent years, a technology is being developed that can measure temperatures at a rate of 2 to 1 in 300 using an alloy resistance wire material made by mixing platinum and cobalt at a certain ratio.

The curve in FIG. 1 (2) shows a cobalt mixing ratio of 0.45 mol, and the curves (3) and (4) show a cobalt mixing ratio of 0.75 mol % and 1.
This shows the sensitivity characteristics in the case of 0.6 mol.
, In the case of (4), there is a discontinuity point, and eventually 0.5 mo
It can be seen that around 1φ is suitable as a sensor.

When constructing a sensor that measures extremely low temperatures using such resistance wire materials, the required characteristics are: (1) good reproducibility of resistance-temperature characteristics;

(2) It has good heat conduction at extremely low temperatures and responds quickly to temperature fluctuations of the measurement target.

(3) The structure is simple and resistant to vibration, shock, and thermal shock.

can be mentioned.

In particular, the sensor is subject to sudden thermal changes (thermal shock) between room temperature 300°C and cryogenic temperature 2°C, so the resistance wire material, winding frame, and insulating coating material are If wires with the same coefficient of linear expansion are not used, strain will be added to the resistance wire material, causing measurement errors.

In addition, the winding frame and coating material must be strong enough not to be damaged even if subjected to sudden thermal shock.

The linear expansion coefficient of 0.3 to 0.75 mo 1 % platinum/cobalt alloy resistance wire material is approximately 9. It is lX10-6.

After studying various insulating materials for the winding frame that have a linear expansion coefficient approximately equal to this linear expansion coefficient, have good thermal conductivity, and can be coated with the same material, we found borosilicate glass (with a linear expansion coefficient of about 9. IX 10-6) was found to be extremely suitable.

The present invention, as shown in Figure 2, uses 0.5mol1% of platinum.
The alloy resistance wire material 1 mixed with nearby cobalt is wound around a lid frame 2 made of borosilicate glass material, and
, is characterized by a structure in which a coating of about 5 mm is applied to the surface.

4.4 IrI is a four-wire lead wire connected to both ends of the resistance wire material 1, and a platinum wire is used.

Alternatively, the lead wire may be constructed by extending the resistance wire material as it is.

According to the present invention, the extremely low temperature region up to about 2 can be controlled with high precision.
It is possible to create an excellent temperature sensor that can measure with high sensitivity and is resistant to shock.

A winding frame made of borosilicate glass is extremely easy to process, and its diameter can be freely selected depending on the location of use.

If the resistance wire material is made of thin material, it is easy to manufacture an extremely small and chip-shaped temperature sensor.

[Brief explanation of the drawing]

FIG. 1 is a sensitivity characteristic diagram of platinum and platinum-cobalt alloy resistance wire materials, and FIG. 2 is a configuration diagram showing an embodiment of the temperature sensor of the present invention. 1... Platinum-cobalt alloy resistance wire material, 2... Borosilicate glass winding wire, 3... Borosilicate glass coating, 4
．． 4'...Leader line.

Claims (1)

[Scope of utility model registration request] A cryogenic temperature sensor made by winding an alloy resistance wire material made of platinum mixed with cobalt of around 0.5 molφ around a borosilicate glass material, and coating the surface with the same glass material as the above glass material.