- Version
- Download 2
- File Size 1.54 MB
- File Count 1
- Create Date February 7, 2024
- Last Updated February 7, 2024
TN 3006A Practical Quadrupole Theory: Miniaturization of Rod Diameter, Length, and Frequency
There are a number of parameters which control quadrupole mass range and transmission, including rod diameter, RF frequency and rod length. With the trend toward miniaturization of analyzers, it is becoming increasingly important to minimize power and size requirements. The question is how small is too small? Mass resolution is very much dependent upon RF frequency, rod length and the energy of the ions as they transmit through the quadrupole. Mass range and voltage requirements are inversely proportional to both the square of rod diameter and the square of RF frequency. The fundamental question is whether an increase in RF frequency can offset the performance loss associated with a reduction in rod diameter. In this work, it was determined that for cases where the emissive area of the ion source is much larger than the acceptance of the quadrupole, absolute transmission is approximately proportional to the square of RF frequency, and the cube of rod diameter.