AC Loss Measuring Apparatus for Superconductors
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Solution Overview
Problem
Existing methods for measuring AC loss in superconductors are limited to a fixed temperature of 4K, making it impossible to measure AC loss at arbitrary temperatures, which is crucial for superconducting apparatuses using high temperature superconductors.
Innovation Solution
An AC loss measuring apparatus is designed with a holder, magnetic field applying coil, multiple cooling members, radiation shield, and temperature measuring means, allowing for adjustable temperature settings and accurate measurement of AC loss at various temperatures by using a conduction cooling system and high thermal resistance members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the specimen is cooled by liquid helium to fix the temperature at 4K, then the measurement accuracy and time constant are improved, but the ability to measure AC loss at arbitrary temperatures is lost
Solution Approach 1:
The invention replaces the static liquid helium cooling system with a dynamic cryocooler system that can actively adjust and maintain the specimen temperature at arbitrary values within a wide temperature range, enabling both high measurement precision and temperature versatility
Solution Approach 2:
The invention changes the temperature parameter from a fixed 4K (liquid helium temperature) to a variable parameter that can be set to any desired temperature within the operating range, achieved through the cryocooler's temperature control capability
2Adaptability or versatility
If a thermal resistance member is introduced to enable arbitrary temperature measurement, then the temperature versatility is improved, but the device complexity increases
Solution Approach 1:
The invention introduces a thermal resistance member (columnar member) as an intermediary between the specimen and the cold head, which enables temperature control and measurement at arbitrary values by creating a thermal gradient that can be measured and controlled
Solution Approach 2:
The cryocooler system serves multiple functions: it cools the specimen to arbitrary temperatures, maintains temperature stability, and works in conjunction with the thermal resistance member to enable temperature measurement, replacing multiple separate systems
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
Enables the measurement of AC loss at arbitrary temperatures, improving the evaluation and design of superconducting systems to prevent quenching and optimize operating conditions for high temperature superconductors.
Implementation Method 1
a first cooling member cooled to a temperature higher than a temperature of the second cooling member; a columnar member disposed to contact both the holder and the second cooling member
Implementation Method 2
a radiation shield formed to confine the holder, the magnetic field applying coil, the first cooling member, the second cooling member and the columnar member in a single space
Implementation Method 3
a vacuum vessel in which to confine the radiation shield
Implementation Method 4
a magnetic field applying coil that applies a magnetic field to the specimen disposed on the holder
Implementation Method 5
first temperature measuring means provided on a surface of the columnar member and at a position nearer to the holder than to the second cooling member; second temperature measuring means provided on the surface of the columnar member and at a position nearer to the second cooling member than to the holder
Data Source
AI summary
An alternating current loss measuring apparatus for superconductors includes a superconductor specimen, a magnetic field applying coil, a radiation shield, a vacuum vessel, first cooling means, and second cooling means. The first cooling means or the second cooling means is provided with a temperature regulating mechanism. The magnetic field applying means and the radiation shield are set to be a first cooling part, whereas the superconductor specimen is set to be a second cooling part, and the first cooling part and the second cooling part are cooled by first and second cooling means, respectively. A high thermal resistance member is disposed between the superconductor specimen and the second cooling means, and temperature measuring means are disposed at at least two positions on the high thermal resistance member. The alternating current loss of a superconductor under an external magnetic field can be measured at each of different temperatures.