GAS-FILLED  LINEAR  QUADRUPOLE  TRAP  WITH  AXIAL 
EMISSION  AS  AN  ION  SOURCE  FOR  MULTIPLE-REFLECTION 
TIME-OF-FLIGHT  MASS  SPECTROMETER

A. N. Verentchikov, B. N. Kozlov, M. I. Yavor, A. S. Trufanov, D. V. Nikitina

Institute for Analytical Instrumentation RAS, Saint-Petersburg

   To combine a multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) with continuous mode ion sources such as those of electrospray type, it has been proposed to accumulate ions in a trap in the intervals be-tween rare accelerator pulses. The ion accumulation scheme offered in the present paper consists of a gas-filled segmental quadrupole with radio-frequency entrainment and axial emission. The paper presents the necessary calculations for the ion trap and analysis of processes of ion capture, collisional cooling, and pulsed emission. Experimental studies of the storage trap have shown almost complete transformation of a continuous ion beam into a pulsed one and the possibility of long-time (for up to a few seconds) ion holding. Satisfactory beam pa-rameters are achieved at sufficient cooling (defined by the dwell time and pressure in the trap, 5 ms∙mTorr), low gas pressure collisions, and at a low trap load (below 100 000 charges). The combination of these two require-ments limits the total beam current at which the ion flux can be converted into minimum width pulses to 3 nA.