Phase-Imagaing Ion-Cyclotron-Resonance (PI-ICR) Basics

The PI-ICR technique is a precision mass spectrometry technique. It determines the cyclotron frequency by finding the phase difference between ion clusters of different accumulation times projected on a position-sensitive detector.

Theory

formulas here

Measurement Technique

• Determine the center spot

  • Inject ions at the center of the trap

  • Reduce residual motion

  • Extract ions towards detector

• Determine magnetron spot

  • Inject ions at radius r (using Lorentz steerers)

  • Free revolution for time t_acc (accumulation time)

  • Extract ions towards detector

• Determine reduced cyclotron spot

  • Inject ions at radius r (using Lorentz steerers)

  • Quadrupolar pulse (to ensure ion motion is entirely reduced cyclotron motion)

  • Free evolution for time t_acc (accumulation time)

  • Quadrupolar pulse to convert motion to magnetron motion (smearing effect if extract at reduced cyclotron)

  • Extract ions towards detector

This procedure will result in 3 spots/ clusters: center, magnetron, and reduced cyclotron.