Quadrupole Mass Spectrometer Pre-Rod Ion Introduction Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The incident efficiency of ions into the quadrupole mass filter in existing quadrupole mass spectrometers is insufficient for accurate analysis, requiring further improvement.
Innovation Solution
A quadrupole mass spectrometer design that includes a pre-rod and an ion optical system with a potential configuration where the exit side electrode is lower than the ionization chamber and pre-rod, and no higher potential structures decelerate ions between the exit side electrode and the pre-rod, along with specific positional relationships between electrodes to optimize ion beam convergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pre-rod is added to match emittance and acceptance, then ion incident efficiency is improved, but device complexity increases
Solution Approach 1:
The quadrupole mass filter is segmented into a pre-rod and main rod sections. The pre-rod serves as an intermediate component that prepares the ion beam by matching emittance before ions enter the main rod, thereby improving incident efficiency without requiring complete redesign of the entire filter system.
Solution Approach 2:
The pre-rod acts as an intermediary component between the ionization chamber and the main rod. It mediates the transition of ions by adjusting their emittance characteristics, serving as a bridge that optimizes the coupling between the ion source and the main filtering section.
2Productivity
If ion beam convergence is increased to improve incident efficiency, then ion introduction efficiency improves, but ion beam velocity decreases
Solution Approach 1:
The pre-rod performs preliminary action on the ion beam by adjusting emittance and optimizing beam parameters before ions enter the main rod. This preliminary optimization allows the main rod to maintain higher ion velocities while still achieving efficient incident coupling, as the beam preparation work is completed in advance by the pre-rod.
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 enhances ion beam velocity and reduces divergence angles, leading to improved ion introduction efficiency and sensitivity of the quadrupole mass spectrometer for accurate analysis.
Implementation Method 1
a DC voltage and an AC voltage are applied to four rod electrodes (main rods) called a quadrupole mass filter arranged around the central axis to generate an oscillating electric field
Implementation Method 2
an ion optical system including an electrostatic lens is arranged between an ionization chamber, which is an ion source, and the quadrupole mass filter
Implementation Method 3
a DC voltage and an AC voltage are applied to four rod electrodes (main rods) called a quadrupole mass filter arranged around the central axis to generate an oscillating electric field so as to pass ions having a predetermined m/z (mass-to-charge ratio)
Data Source
AI summary
A quadrupole mass spectrometer includes: a quadrupole mass filter including a pre-rod; an ionization chamber; and an ion optical system that guides ions generated in the ionization chamber to the pre-rod of the quadrupole mass filter, wherein: a potential of an exit side electrode of the ion optical system is lower than a potential of the ionization chamber and a potential of the pre-rod of the quadrupole mass filter; and there is no structure that has a higher potential than the exit side electrode and decelerates the ions between the exit side electrode and the pre-rod.