Abstract: The total number of ions created br obtained during an ionization or ion introduction event in a Fourier transform ion cyclotron resonance mass spectrometer are determined either by using an on-resonance experimental technique or an off-resonance experimental technique. Both techniques exploit ion magnetron motion. In the on-resonance technique the spectrometer is excited in the magnetron mode and the single resonance signal resulting from this excitation is detected to determine the total number of ions. In the off-resonance technique the magnetron mode is excited at a frequency that is near the magnetron frequency while simultaneously detecting the resulting ion motion. The off-resonance technique leaves the ion population in a state that is amenable to subsequent analysis.

Abstract: An electrical feed through for use in a high temperature oven such as the oven in a gas chromatograph. The feed through includes printed circuit boards which are maintained in compression to prevent the boards from physically separating at the elevated temperatures used in the oven. The structure that provides the compression also does not allow any flexure, torsional or longitudinal stress on the boards. The boards include an enhanced connector pad which is made from a continuous annular copper ring which is connected to all of the conductive layers of the board.