Sample ionisation using a pulsed laser source

A method of mass and/or ion mobility spectrometry comprising:

• providing a target sample supported on a sample plate;
• providing a laser source arranged and adapted to generate a series of laser pulses;
• moving a focal point of the laser source substantially continuously across the sample plate, wherein respective packets of ions are generated by respective laser pulses impinging upon respective locations on the target sample supported on the sample plate;
• and
• performing plural cycles of ion analysis, wherein each cycle of ion analysis is performed for a pixel in an output image and comprises producing a set of spectral data that corresponds to one or more of the packets of ions;
• wherein the series of laser pulses are gated, stopped or blocked in between cycles of ion analysis for two adjacent pixels.

A mass and/or ion mobility spectrometer comprising:

• a sample plate arranged and adapted to support a target sample;
• a laser source arranged and adapted to generate a series of laser pulses;
• and
• a control system arranged and adapted:
• (i) to move a focal point of the laser source substantially continuously across the sample plate, wherein respective packets of ions are generated by respective laser pulses impinging upon respective locations on the target sample supported on the sample plate;
• (ii) to cause the laser source to generate a series of laser pulses during a cycle time T1 in respect of a pixel;
• (iii) to gate, stop or block the series of laser pulses during a subsequent inter-cycle time period T0 so that substantially no ions or fewer ions are generated during the inter-cycle time period T0;
• and
• (iv) to repeat steps (i)-(iii) one or more times such that, while the focal point of the laser source is being moved substantially continuously in between respective locations on the target sample for two adjacent pixels, the series of laser pulses are gated, stopped or blocked during the inter-cycle time period T0 in between the cycle times T1 for the two adjacent pixels.

A method of mass and/or ion mobility spectrometry comprising:

• (i) providing a target sample supported on a sample plate;
• (ii) providing a laser source arranged and adapted to generate a series of laser pulses;
• (iii) moving a focal point of the laser source substantially continuously across the sample plate, wherein respective packets of ions are generated by respective laser pulses impinging upon respective locations on the target sample supported on the sample plate;
• (iv) causing the laser source to generate a series of laser pulses during a cycle time T1 in respect of a pixel;
• (v) gating, stopping or blocking the series of laser pulses during a subsequent inter-cycle time period T0 so that substantially no ions or fewer ions are generated during the inter-cycle time period T0;
• and
• (vi) repeating steps (iii)-(v) one or more times such that, while the focal point of the laser source is moving substantially continuously in between respective locations on the target sample for two adjacent pixels, the series of laser pulses are gated, stopped or blocked during the inter-cycle time period T0 in between the cycle times T1 for the two adjacent pixels.