Techniques for Mass Spectrometry - Using MEMS Pirani Sensor In Vacuum to Measure Pressure In Collision/Cooling Cells and Intermediate Vacuum Chambers

摘要

This disclosure describes using a microelectromechanical system (MEMS) pirani sensor in-vacuum for measuring pressure directly on collision/cooling cells, and at various intermediate high vacuum stages (greater than 1e-4 Torr) for mass spectrometers. In more detail, ion fragmentation through collisions with neutral gas molecules (e.g., collision induced dissociation CID, higher energy collisional dissociation HCD, pulsed q-value dissociation PQD) is one of the commonly used techniques in mass spectrometers to fragment complex molecules. Implementation of this MSn technique generally involves an enclosed collision cell, where parent ions are collided with neutral gas molecules (N2, Ar, or He). These collisions convert ion translation energy into vibrational energy, and can subsequently lead cleave parent ion bonds toform smaller daughter ions.