Shield Portion in Orthogonal Acceleration TOF Mass Spectrometer
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Solution Overview
Problem
The electric field fluctuations in the transfer electrode unit of orthogonal acceleration time-of-flight mass spectrometers due to high voltages applied to the flight tube lead to decreased resolution, sensitivity, and measurement accuracy, and increasing the number of electrodes to mitigate this issue raises manufacturing costs and tolerance issues.
Innovation Solution
Incorporating a shield portion between the transfer electrode unit and the flight tube, formed by part of the loop electrodes, to prevent the electric field from the flight tube from entering the transfer electrode unit, thereby maintaining a stable electric field and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the distance between the flight tube and transfer electrode unit is reduced to minimize electric field interference, then electric field stability improves, but the number of electrodes increases and manufacturing costs rise
Solution Approach 1:
A shield electrode is introduced as an intermediary component between the flight tube and the transfer electrode unit. This shield electrode blocks the electric field lines from the high voltage flight tube from directly entering the transfer electrode unit, thereby stabilizing the electric field in the transfer region without requiring the electrodes to be placed closer together.
Solution Approach 2:
The electrode system is segmented into distinct functional zones: the flight tube electrode, the shield electrode, and the transfer electrode unit. This segmentation allows each component to perform its specific function independently, with the shield electrode specifically tasked with electric field management, thus avoiding the need to increase the total number of electrodes in the transfer unit.
2Measurement precision
If additional shield electrodes are added to block electric field interference, then measurement accuracy improves, but manufacturing costs and component tolerance accumulation increase
Solution Approach 1:
The shield electrode serves multiple functions: it acts as an electric field shield to protect the transfer electrode unit, and simultaneously functions as part of the ion guidance system. This multi-functionality reduces the need for additional dedicated shield components, thereby controlling manufacturing costs while maintaining measurement accuracy.
Solution Approach 2:
The shield electrode is designed to be formed by part of the existing loop electrodes in the transfer electrode unit, rather than being a completely separate component. This self-service approach utilizes the existing electrode structure to provide shielding function, reducing the need for additional manufactured parts and associated costs.
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 suppresses electric field fluctuations in the transfer electrode unit, enhancing measurement accuracy and reducing manufacturing costs by utilizing existing electrodes to form the shield portion.
Implementation Method 1
a high voltage of about 7 kV is applied to the flight tube... the electric field derived from the high voltage applied to the flight tube enters the transfer electrode unit to cause fluctuation in the electric field
Implementation Method 2
By applying a voltage to each of these electrodes, an electric field is formed on an inner side of each electrode, and the ions are guided to the orthogonal acceleration unit through the electric field
Implementation Method 3
An orthogonal acceleration region where the ions incident from the transfer electrode unit are accelerated in a direction orthogonal to the incident direction of the ions is formed in the orthogonal acceleration unit
Implementation Method 4
the time of flight of the ion until the ion reaches the detector is measured, and the mass-to-charge ratio m/z of the ion is calculated on the basis of the time of flight
Data Source
AI summary
A transfer electrode unit (240) is configured by coaxially arranging a plurality of loop electrodes (241A, 241B, 241C), and guides ions to an orthogonal acceleration region (242C) by allowing the ions to pass through an inner side of the plurality of electrodes (241A, 241B, 241C) each of which is applied with a voltage. A voltage having a higher absolute value than the voltage applied to the plurality of electrodes (241A, 241B, 241C) is applied to a flight tube (246), and the ions accelerated in the orthogonal acceleration region (242C) are introduced to a flight space formed in the flight tube (246). A shield portion (241F) is provided between the transfer electrode unit (240) and the flight tube (246), and suppresses that an electric field derived from the voltage applied to the flight tube (246) enters the transfer electrode unit (240).