Apparatus for cooling a sample environment and method of protecting a sample from vibrations of a vessel of a continuously cooled dry cryostat

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Solution Overview

Problem

Continuously cooling a dry cryostat using a pulse tube poses a challenge due to vibrations that propagate towards the sample, which existing technologies fail to effectively mitigate.

Innovation Solution

The apparatus employs a sample holder with flexible heat-conducting bridges connecting it to the vessel, allowing for relative movement and decoupling from rigid mechanical connections, thereby reducing vibration transmission. The vessel is divided into segments with different thermal conductivity materials and includes shields and an elastic vacuum portion to enhance thermal and mechanical isolation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a pulse tube is used to continuously cool a dry cryostat, then continuous cooling is achieved, but vibrations are generated that propagate towards the sample

Engineering Contradiction:
Improvecontinuous cooling durationVSAvoidvibrations affecting sample
Core Design Contradiction:
Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The vessel is divided into multiple segments (first segment, second segment, third segment) separated by first and second structures. This segmentation allows each segment to be independently supported and isolated, preventing vibration propagation from the pulse tube across the entire vessel while maintaining continuous cooling through the segmented structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Flexible heat-conducting bridges are introduced as intermediary elements between the sample holder and the vessel structures. These bridges provide thermal conduction pathways while mechanically decoupling the sample holder from vibration sources, serving as mediators that transfer heat without transmitting vibrations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If rigid mechanical connectors are used to connect the sample holder to the vessel, then structural stability is maintained, but vibrations are transmitted to the sample

Engineering Contradiction:
Improvestructural stability of sample holder connectionVSAvoidvibration transmission to sample
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

Flexible heat-conducting bridges replace rigid mechanical connectors to connect the sample holder to the vessel structures. These flexible bridges maintain structural connection and thermal conduction while accommodating relative movements and isolating the sample holder from vibrations through their flexible nature.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The connection system transitions from static rigid connectors to dynamic flexible bridges that can adapt to vibrations and relative movements. The flexible bridges allow the system to dynamically respond to vibrations by deforming rather than rigidly transmitting them, maintaining stability while reducing vibration transmission.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If flexible heat-conducting bridges are used to connect the sample holder to the vessel, then vibration transmission is reduced, but thermal conduction efficiency may be compromised

Engineering Contradiction:
Improvevibration transmission reductionVSAvoidthermal conduction loss
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The flexible heat-conducting bridges are designed as composite structures that combine materials or structural features providing both flexibility for vibration isolation and sufficient thermal conductivity for efficient heat transfer. This composite approach allows simultaneous achievement of vibration reduction and thermal conduction efficiency.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different portions of the flexible heat-conducting bridges may have different properties optimized for specific functions - some regions optimized for flexibility and vibration isolation, while other regions optimized for thermal conduction. This local quality differentiation allows the bridge to perform both vibration reduction and efficient heat transfer.

Inventive Principle:
Principle #3Local quality

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 configuration effectively reduces vibrations and maintains efficient cooling, allowing the sample to operate at extremely low temperatures without interference from pulse tube-induced vibrations, ensuring stable operation of sensitive equipment like quantum computing devices.

Implementation Method 1

The sample holder is connected, by a first flexible heat-conducting bridge, to a first structure separating the lower segment and the middle segment. The sample holder is connected, by a second flexible heat-conducting bridge, to a second structure separating the middle segment and the upper segment.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The vessel may have multiple outer layers with evacuated space between the layers. In this way, the temperature in the vessel may decrease towards the center of the bottom of the vessel, making the sample environment to coincide with the coldest portion of the space inside the vessel.

Methodology Applied
Scientific EffectThermal insulation via vacuum: Thermal Insulation

Data Source

PatentEP4491982A1Apparatus for cooling a sample environment and method of protecting a sample from vibrations of a vessel of a continuously cooled dry cryostat
Publication Date: 2025.01.15 TECHNISCHE UNIVERSITAT MUNCHEN
  • EP4491982A1 patent drawingFigure 1
  • EP4491982A1 patent drawingFigure 1a
  • EP4491982A1 patent drawingFigure 2

AI summary

Provided is an apparatus for cooling a sample environment. The apparatus comprises a vessel (14) and a sample holder (16). The vessel (14) is divided into a lower segment (18), a middle segment (20), and an upper segment (22). The sample holder (16) traverses the upper segment (22) and the middle segment (20) and extends into the sample environment (12) which is in the lower segment (18). The sample holder (16) is connected to a first structure (34a) separating the lower segment (18) and the middle segment (20), by a first flexible heat-conducting bridge (32). The first structure (34a) is configured to be cooled below a first temperature. The sample holder (16) is connected to a second structure (34a) separating the middle segment (20) and the upper segment (22), by a second flexible heat-conducting bridge (32). The second structure (34b) is configured to be cooled below a second temperature, the second temperature being above the first temperature. Said flexible heat-conducting bridges (23) are configured to allow for a relative movement between the vessel (14) and the sample holder (16).