Abstract: In a gas inlet structure for an ion source, including a capillary for the admission of a sample gas, which capillary is disposed in a guide tube for discharging a sample gas into the guide tube, the guide tube has an open end disposed in the ion source. The guide tube includes a valve for the pulsed admission of a carrier gas to the guide tube. The guide tube, the valve and the capillary are supported in a sealed support housing from which the guide tube with the capillary disposed therein projects into the ion source for supplying thereto the sample gas in a pulsed manner.

Abstract: In a method for producing a directed gas jet wherein a guided sample gas beam is generated and an auxiliary gas beam is generated and directed and guided in the same direction as, but separated from, the sample gas beam, a pulsed carrier gas stream is generated and combined with the sample gas beam such that the sample gas beam is separated into spaced pulses which are embedded between the axially spaced pulses of the carrier gas beam and the carrier gas beam with the sample gas beam embedded therein is combined with the auxiliary gas beam such that the carrier and sample gas beam is radially enveloped by the auxiliary gas beam to from the directed gas jet of a carrier and sample gas pulses enveloped in the auxiliary gas beam.