LTQ Orbitrap XL Hardware Manual

Functional Description
Orbitrap Analyzer
Figure 1-11. Layout of the instrument, also showing the applied voltages
Extraction of Ion Packets
nitrogen collision gas (bath gas) is used for dissipating the kinetic energy
of ions injected from the LTQ XL and for cooling them down to the axis
of the curved linear trap.
Voltages on the end apertures of the curved trap (Trap and Gate
apertures) are elevated to provide a potential well along its axis. These
voltages may be later ramped up to squeeze ions into a shorter thread
along this axis. The RF to the C-Trap (“Main RF”) is provided by the
CLT RF main board. (See page 1-50.) Trap and gate DC voltages as well
as RF voltages to octapole 1 are all provided by the ion optic supply
board. (See page 1-46.) High voltages to the lenses are provided by the
high voltage power supply board. (See page 1-53.)
For ion extraction, the RF on the rods of the C-Trap is switched off and
extracting voltage pulses are applied to the electrodes, pushing ions
orthogonally to the curved axis through a slot in the inner hyperbolic
electrode. Because of the initial curvature of the curved trap and the
subsequent lenses, the ion beam converges on the entrance into the
Orbitrap. The lenses form also differential pumping slots and cause
spatial focusing of the ion beam into the entrance of the Orbitrap. Ions
are electrostatically deflected away from the gas jet, thereby eliminating
gas carryover into the Orbitrap.
1-14 LTQ Orbitrap XL Hardware Manual Thermo Fisher Scientific