Gradient Coil Cooling Channel Layout for High MRI Gradient Density
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Solution Overview
Problem
Existing gradient coil units in MRI scanners face challenges in generating high magnetic field gradients with strong rise and fall rates while efficiently dissipating the heat generated by power loss, particularly when examining the head of a subject with strong magnetic fields exceeding 3 Tesla.
Innovation Solution
A gradient coil unit design featuring a primary conductor structure with two serially connected sections and a cooling channel arranged in a spiral configuration, allowing for efficient cooling and high current density, enabling the generation of magnetic field gradients with maximum amplitudes of up to 500 mT/m and rise and fall rates of several hundred kA/s.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high current density is used to generate strong magnetic field gradients, then image resolution and gradient strength are improved, but heat generation and power loss increase
Solution Approach 1:
The primary electrical conductor is divided into two serially connected sections with a cooling channel positioned between them. This segmentation allows the conductor to be cooled more effectively during operation, enabling sustained high current density without excessive heat accumulation, thus maintaining high image resolution while reducing power loss.
Solution Approach 2:
A cooling channel is introduced as an intermediary element between the two conductor sections. This cooling channel facilitates heat dissipation from the conductor, allowing the system to operate at high current densities required for strong magnetic field gradients and high image resolution without suffering from excessive power loss due to heat generation.
2Power
If high current density is used to generate strong magnetic field gradients, then gradient strength is improved, but heat generation increases
Solution Approach 1:
The primary electrical conductor is divided into two serially connected sections with a cooling channel positioned between them. This segmentation allows the conductor to be cooled more effectively during operation, enabling sustained high current density without excessive heat accumulation, thus maintaining high image resolution while reducing power loss.
Solution Approach 2:
A cooling channel is introduced as an intermediary element between the two conductor sections. This cooling channel facilitates heat dissipation from the conductor, allowing the system to operate at high current densities required for strong magnetic field gradients and high image resolution without suffering from excessive power loss due to heat generation.
3Power
If conventional cooling designs are used, then device simplicity is maintained, but cooling efficiency is insufficient for high gradient operation
Solution Approach 1:
The cooling channel is nested between the two sections of the primary electrical conductor, with the conductor sections arranged to enclose or surround portions of the cooling channel. This nested arrangement allows efficient cooling of the high-power gradient coil while integrating the cooling function into the existing conductor structure without requiring separate external cooling 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
The design enables robust operation with high current density, efficient cooling, and the generation of strong magnetic field gradients, improving image acquisition speed and resolution, especially for head examinations, while minimizing power loss and heat generation.
Implementation Method 1
each primary conductor structure unit is formed from a primary electrical conductor... arranged such that the cooling channel is arranged at least partially between the two sections, the two sections and the cooling channel run at least partially parallel, and the two sections each have a contact surface with the cooling channel
Implementation Method 2
cooling channel... allowing for efficient cooling and high current density, enabling the generation of magnetic field gradients with maximum amplitudes of up to 500 mT/m and efficient heat dissipation
Implementation Method 3
A magnetic field gradient is generated by driving the primary coil with electric currents whose amplitudes reach several hundred A and which are subject to frequent and rapid changes in current direction with rise and fall rates of several hundred kA
Data Source
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AI summary
The invention relates to a gradient coil unit comprising a gradient coil surrounding a cylindrical axis and designed to generate a magnetic field gradient in a first spatial direction, which gradient coil comprises a hollow cylindrical primary layer comprising two primary conductor structure units and a cooling channel, wherein each primary conductor structure unit of the two primary conductor structure units is formed from a primary electrical conductor, which primary electrical conductor is divisible into two serially connected sections and is arranged such that - the cooling channel is arranged at least partially between the two sections, - the two sections and the cooling channel run at least partially parallel, and - the two sections each have a contact surface with the cooling channel.