Half-Wavelength RF Transmission Line for Remote Quadrupole Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing quadrupole analyzers in mass spectrometers face challenges in delivering precise RF signals over long distances while protecting sensitive control/analysis subsystems from ionizing radiation, which degrades semiconductor components, and require inefficient thermionic rectifiers for signal measurement.
Innovation Solution
A resonant transmission line with a half-wavelength electrical length is used to convey RF signals, allowing remote measurement with semiconductor diodes, and step-up transformers to maintain signal amplitude, keeping vulnerable components safe from radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control/analysis subsystem is remotely located to protect it from ionizing radiation, then the safety of semiconductor components is improved, but the distance for RF signal transmission increases causing signal loss and degradation
Solution Approach 1:
A resonant transmission line acts as an intermediary between the remotely located control/analysis subsystem and the quadrupole subsystem. This resonant line is tuned to the operating frequency and has an electrical length of one-half wavelength, enabling it to efficiently transfer RF signal voltage from the remote control subsystem to the quadrupole analyzer while maintaining signal integrity over the extended distance.
2Ease of operation
If a thermionic rectifier is used to measure RF signal voltage in the radiation environment, then measurement capability is maintained, but device complexity and heater supply requirements increase
Solution Approach 1:
The patent replaces the thermionic rectifier (vacuum tube-based) with a semiconductor diode rectifier. This substitution eliminates the need for heater supply and associated complexity while maintaining the rectification and measurement functionality. The semiconductor diode is positioned at the remote control/analysis subsystem where it can operate without exposure to ionizing radiation.
3Stability of the object's composition
If the RF signal generator is fixed frequency and crystal controlled, then frequency stability is improved, but adaptability to different mass ranges and analyzer properties deteriorates
Solution Approach 1:
The patent introduces a variable frequency oscillator that can be tuned to different frequencies depending on the required mass range and analyzer properties. This dynamic frequency adjustment capability allows the system to adapt to different operating conditions while maintaining frequency stability through proper tuning and the use of the resonant transmission line at the operating frequency.
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 accurate, efficient, and reliable delivery of RF signals over extended distances with reduced signal loss and component degradation, using semiconductor rectifiers instead of thermionic diodes.
Implementation Method 1
The transmission line is resonant at the frequency of an RF signal to be conveyed therethrough and has an electrical length of one-half wavelength (λ/2) of the operating frequency
Implementation Method 2
A property of a resonant transmission line is that it manifests the same RF voltage amplitude at both ends of the transmission line, which enables a semiconductor diode to be used as a rectifier
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A system for conveying a time-varying voltage signal from a first subsystem to a second subsystem, and for monitoring and controlling the time-varying voltage signal, comprises a transmission line having a first end and a second end, extending from the first end at the first subsystem to the second end at the second subsystem. The transmission line is configured to be un-terminated, and have an electrical length substantially equal to a multiple of one half wavelength of the time-varying voltage signal. The system may further comprise an adaptive control configured to couple the time-varying voltage signal to the first end, and adjust a generator of the time-varying voltage signal based on a sampling of the time-varying voltage signal at the first end, and at least one transformer at the second subsystem electrically coupled to the second end and configured to increase an amplitude of the time-varying voltage signal.