Method and apparatus

A method of directing charged particles and reactive neutral particles into a trapping region of a linear ion trap, the method comprising:

• releasing a gas pulse from a gas supply into the entrance of a conduit extending in the direction of the trapping region;
• generating a discharge in the gas pulse in the conduit, thereby generating charged particles from the gas and accelerating the generated charged particles in the direction of the trapping region;
• converting a fraction of the accelerated charged particles into reactive neutral particles by transporting the charged particles through an incandescent electron source arranged between the discharge and the trapping region;
• and
• directing the remainder fraction of the accelerated charged particles together with the converted reactive neutral particles in the direction of the trapping region.

An apparatus comprising:

• a linear ion trap disposed in a vacuum housing and having a longitudinal axis and a trapping region configured to store analyte ions;
• and
• a charged particle source disposed in the vacuum housing and coupled to the linear ion trap, the charged particle source comprising:
• a conduit extending towards the trapping region in a direction perpendicular to the longitudinal axis of the linear ion trap and having an entrance and an exit;
• a pulse valve disposed in fluid communication with the conduit and configured to release a gas pulse from a gas supply into the entrance of the conduit;
• and
• a discharge device electrically coupled to an electrical potential supply and disposed between the entrance and the exit of the conduit, the electrical potential supply being configured to apply a high voltage to the discharge device to generate a discharge in the gas pulse in the conduit, thereby (a) generating charged particles from the gas to establish a high-pressure transient in the conduit while minimizing a gas load to the linear ion trap and (b) accelerating the generated charged particles towards the trapping region in the direction perpendicular to the longitudinal axis of the linear ion trap to activate analyte ions stored in the trapping region.

An apparatus comprising:

• a linear ion trap disposed in a vacuum housing and comprising two pairs of pole electrodes and a radiofrequency (RF) electrical potential supply configured to apply respective RF waveforms to the pairs of pole electrodes, thereby forming a RF trapping field component to trap analyte ions radially in a trapping region of the linear ion trap for processing of the analyte ions therein;
• and
• a charged particle source disposed in the vacuum housing and coupled to the linear ion trap, the charged particle source comprising a pulse valve, a conduit extending in the direction of the trapping region of the linear ion trap and having an entrance in fluid communication with the pulse valve and an exit, and a discharge device electrically coupled to an electrical potential supply and disposed between the entrance and the exit of the conduit, wherein the pulse valve is configured to release a gas pulse from a gas supply into the entrance of the conduit, and wherein the electrical potential supply is configured to apply a high voltage to the discharge device to generate a discharge in the gas pulse in the conduit, thereby (a) generating charged particles from the gas entrained in a travelling gas pulse to establish a high-pressure transient in the conduit while minimizing a gas load to the linear ion trap, and (b) accelerating the generated charged particles in the direction of the trapping region to activate the analyte ions in the trapping region.