Magnetic Field Measurement and Control for Ion Therapy
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Solution Overview
Problem
Current methods for measuring and closed-loop controlling magnetic fields in electromagnets, particularly in particle accelerators, are hindered by hysteresis and eddy currents, leading to field errors that affect ion beam accuracy and require time-consuming calibration, limiting the efficiency of ion therapy.
Innovation Solution
A device with a first measuring device for absolute magnetic field measurement and a second for field alterations, combined with parallel integrators for real-time integration and calibration, allowing simultaneous measurement and calibration without interrupting the process, thus enabling precise and rapid control of the magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed to compensate for hysteresis and eddy currents, then measurement precision is improved, but loss of time increases due to time-consuming calibration procedures
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements in advance during idle periods or between ion beam cycles. The calibration data obtained from these preliminary measurements is stored and applied during subsequent ion beam delivery, eliminating the need to interrupt therapy for calibration while maintaining measurement precision through pre-compensated values.
2Productivity
If real-time measurement and calibration are performed simultaneously, then productivity is improved, but device complexity increases due to multiple integrators and measuring devices
Solution Approach 1:
The patent segments the measurement and calibration functions into distinct modules: a first measuring device for absolute field strength, a second measuring device for field alterations, and multiple parallel integrators for different calculation paths. This segmentation allows simultaneous operation of measurement and calibration while maintaining manageable system complexity through modular design.
Solution Approach 2:
The patent introduces intermediary computational elements (integrators and evaluation units) that mediate between the raw measurements from the measuring devices and the final control signals. These intermediaries process the measurement data in real-time, enabling simultaneous measurement and calibration without direct interference between the functions, thus improving productivity while containing complexity.
3Manufacturing precision
If hysteresis and eddy currents are compensated for, then manufacturing precision is improved, but device complexity increases due to additional correction mechanisms
Solution Approach 1:
The patent implements feedback mechanisms where the measured magnetic field values (both absolute and alteration components) are continuously fed back to the control system. This feedback enables real-time compensation for hysteresis and eddy currents by adjusting the electromagnet current based on actual field conditions, improving manufacturing precision while using software-based control rather than additional hardware complexity.
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 solution enables real-time closed-loop control of the magnetic field, reducing calibration time and minimizing the impact of hysteresis and eddy currents, thereby improving the accuracy and efficiency of ion beam delivery in particle accelerators.
Implementation Method 1
a first measuring device for purposes of measuring the absolute magnetic field strength of the magnetic field
Implementation Method 2
a second measuring device for purposes of measuring the alteration of the magnetic field strength of the magnetic field
Implementation Method 3
at least two integrators for purposes of determining the magnetic field strength of the alteration of the magnetic field strength measured in the second measuring device by integration
Implementation Method 4
The electromagnets are provided with a gap, through which the ion beam is directed. Dipoles usually have a rectangular cross-section with a gap in the interior and possess two poles; these are arranged opposite one another and are directed into the interior of the dipole. A coil is arranged on two opposite sides of the dipole.
Implementation Method 5
The electromagnets usually have a core of ferromagnetic iron, so that by virtue of the high permeability of the iron, the magnetic flux is mainly directed through the iron.
Implementation Method 6
The ferromagnetic iron possesses hysteresis, so that the magnetic field generated by the magnet not only depends on the field currently induced externally by the coil through which the current flows, but also depends on the hysteresis of the magnetisation.
Implementation Method 7
Eddy currents are a further influencing variable that occur in an electromagnet. Eddy currents are electric currents that are induced in a conducting material as a result of a magnetic field that alters with time.
Data Source
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AI summary
A device for the measuring and closed-loop control of a magnetic field generated by means of an electromagnet (5, 12, 15), comprising a first measuring device (10) for purposes of measuring the absolute magnetic field strength of the magnetic field, a second measuring device (11) for purposes of measuring the alteration of the magnetic field strength of the magnetic field, at least two integrators (20) for purposes of determining the magnetic field strength of the alteration of the magnetic field strength measured in the second measuring device (11), which integrators are arranged in parallel to one another, calibration means, a unit for purposes of comparing the magnetic field strength measured by the first measuring device (10) and the second measuring device (11), and a further unit for purposes of comparing the measured magnetic field strength with a prescribed design field strength, and a method.