Cryogenic Detector Temperature Stabilization Using an EM Stage

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Solution Overview

Problem

Mechanical cooling devices cause significant temperature fluctuations that are disruptive to sensitive sensor devices, such as superconducting radiation detectors, which existing technologies struggle to stabilize effectively without prolonging the cooling process.

Innovation Solution

A demagnetization stage (EM stage) is thermally coupled to the sensor device and/or cold head, using magnetic field changes to compensate for temperature fluctuations by releasing heat during magnetization and cooling down when the field is lowered, allowing the EM stage to act as both a cooler and a heater, with push-pull magnetic field adjustments to match the frequency of fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a mechanical cooling device is used to cool the sensor device, then the sensor device can be cooled to the desired temperature, but significant temperature fluctuations occur that disrupt sensor operation

Engineering Contradiction:
Improvecooling temperatureVSAvoidtemperature stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

An EM stage is introduced as an intermediary between the mechanical cooling device and the sensor device. This intermediary uses magnetic field changes to actively compensate for temperature fluctuations, absorbing thermal disturbances from the mechanical cooler and preventing them from reaching the sensor, while maintaining the desired low temperature operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the operational parameters of the cooling system by superimposing magnetic field changes on the mechanical cooling process. By varying the magnetic field strength dynamically, the EM stage modulates its heat absorption/release characteristics to counteract temperature fluctuations, transforming a static cooling approach into a dynamically controlled thermal management system.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a heating element is used to stabilize temperature by counter-heating, then small temperature fluctuations can be reduced, but the temperature stabilization process takes a very long time

Engineering Contradiction:
Improvetemperature stabilityVSAvoidcooling time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The EM stage employs periodic magnetic field changes synchronized with the cooling cycle fluctuations. By applying magnetic field variations at the appropriate frequency and phase, the system actively counteracts temperature deviations in real-time, achieving rapid stabilization without the prolonged heating periods required by conventional counter-heating methods.

Inventive Principle:
Principle #19Periodic action

3Stability of the object's composition

If the EM stage is weakly coupled to the cold head, then temperature fluctuations are dampened, but the cooling process from room temperature to desired temperature takes a very long time

Engineering Contradiction:
Improvetemperature fluctuation dampingVSAvoidcooling duration
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The EM stage operates continuously throughout the cooling process, providing active temperature compensation from the moment cooling begins. This continuous action ensures that temperature fluctuations are dampened throughout the entire cooling trajectory, eliminating the need for weak thermal coupling that would otherwise be required to achieve fluctuation damping, thereby maintaining fast cooling speeds.

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces temperature fluctuations, stabilizes the sensor device, and reduces power requirements, enabling faster cooling while maintaining the EM stage within its dynamic range, thus improving temperature stability and efficiency.

Implementation Method 1

In an EM stage, the magnetic moments of a paramagnetic material, such as a paramagnetic salt, are at least partially aligned by applying a magnetic field. During this magnetization, heat is released, which is usually dissipated by a pre-cooling stage. If the magnetic field is now lowered, the alignment of the magnetic moments is canceled again. The energy required for this is withdrawn from the material and the material cools down.

Methodology Applied
Scientific EffectAdiabatic demagnetization: Adiabatic Cooling

Implementation Method 2

During this magnetization, heat is released

Methodology Applied
Scientific EffectMagnetization heating: Heating

Data Source

PatentEP2035905B1Cryogenic detector device comprising temperature stabilization device
Publication Date: 2010.09.15 VERICOLD TECH
  • EP2035905B1 patent drawingFigure 1~2
  • EP2035905B1 patent drawingFigure 3~4
  • EP2035905B1 patent drawingFigure 5~6

AI summary

A cryogenic detector device comprising a mechanical cooling device and a temperature stabilization device is disclosed, wherein the temperature fluctuations occurring with mechanical cooling devices are considerably reduced. The temperature fluctuations occurring with a mechanical cooling device can be compensated for by means of a demagnetization stage (EM stage). The EM stage is thermally coupled to the sensor device and/or the refrigeration head. With an EM stage, the magnetic moments of a paramagnetic material, such as a paramagnetic salt, are oriented at least partially by applying a magnetic field. During this magnetization heat is released, which is typically removed by a precooling stage. If the magnetic field is lowered, the orientation of the magnetic fields is cancelled again. The energy required is taken from the material, the material cools off. In the present invention, both the typically utilized cooling effect of an EM stage and the “heating effect” thereof when increasing the magnetic field can be used. By increasing the magnetic field the EM stage acts as a “heating device“ and by lowering the magnetic field the EM stage acts as a cooling device.