Laser desorption ion source with ion guide coupling for ion mass spectroscopy

An ion analyzing system comprising:

• a first vacuum chamber;
• a second vacuum chamber downstream from the first vacuum chamber, the first and second vacuum chambers being separated by a partition having an aperture formed therein to allow passage of ions from the first vacuum chamber into the second vacuum chamber;
• a laser desorption ion target disposed in the first vacuum chamber;
• and
• first and second multipole ion guides disposed in the first vacuum chamber, the first multipole ion guide being adjacent the target and the second multipole ion guide being between the first multipole ion guide and the aperture, the first multipole ion guide having an inscribed diameter greater than an inscribed diameter of the second multipole ion guide and being disposed to accept a plume of ions generated from the laser desorption ion target and being operated to guide ions in the plume to enter the second multipole ion guide, the second multipole ion guide being operated to guide the ions to go through the aperture and enter the second vacuum chamber.