Quadrupole deflector

Auger analysis of small features. The primary electron beam column is similar to that in electron microscopes, and it may contain both electrostatic and magnetic lenses for beam focussing as well as quadrupole deflectors for beam steering and octopole lenses for beam shaping. 

Fig. 1.5. Experimental setup of the high-frequency laser vaporization cluster ion source driven by a 100-Hz Nd Yag laser for the production of ion clusters, ion optics with a quadrupole deflector, and quadrupole mass Alter for size-selection and deposition the analysis chamber with a mass spectrometer for thermal desorption spectroscopy (TDS), a Fourier transform infrared spectrometer, a spherical electron energy analyzer for Auger electron spectroscopy (AES) for in situ characterization of the clusters [73]...

A detailed description of the interacting beams apparatus used in the present work can be found elsewhere [12], In short, positive ions are extracted from a plasma-type ion source and accelerated to beam energies that can be varied between 2.5 and 5 keV. Negative ions are produced in the beam by double sequential charge exchange in a cesium vapor. A pair of electrostatic quadrupole deflectors (QD1, QD2) is used to direct the negative ion beam into and out of the path of the laser beams, as shown schematically in Fig. 2. The ion-laser interaction region is defined... 

Fig. 2 Portion of the collinear laser-ion beam apparatus. QDl, QD2, electrostatic quadrupole deflectors CEM, channel electron multiplier DP, deflection plates PD, positive ion detector FC, Faraday cup ND, neutral particle detector CG, conducting glass plate AP, aperture MP, metal plate A, any element. The distance between QDl and QD2 is approximately 0.5 m.

Fig. 4 shows selected energy levels of the He /He systems. The Is3s4s state of He is situated just below the He (3 S) threshold. This state, which is excited with laser (O, rapidly autodetaches via the 2 Sks and 2 Pk.p channels. Following the decay, the residual He atom will be left in either the or 2 P excited states. Two different laser frequencies and a" were applied separately in the resonance ionization scheme used to monitor the population of the 2 8 and 2 states. The frequency 0)2 was chosen to induce a transition between the 2 S and the 24 P states of the He atom, when photodetachment into the 2 Sks channel was studied. The frequency co" induced a resonance transition between the 2 P and 26 D states of He, when photodetachment into the 2 Pkp channel was studied. The population of both the high lying Rydberg states were efficiently depleted by the electric field of the second quadrupole deflector and He+ ions thus produced were recorded as a function of frequency of laser m,. The output of laser w, was attenuated to avoid... 

Fig. 8. Schematic drawing tandem mass spectrometer in Z configuration for coaxial infrared laser excitation. Aperture lenses have been omitted for clarity. Comptonents (a) Nozzle, (b) skimmer, (c) electron gun, (d) and (i) quadrupole mass filter, (e) and (g) quadrupole deflector, (f) octopole ion guide, (h) CO2 laser, (j) ion conversion dynode, and (k) secondary eiectron multiplier. ...

ACIS with a Quadrupole Deflector at the Universitat Rostock... 

The setup at the Universitat Rostock utilizes an ACIS to produce a continuous cluster beam (see Fig. 3.9). The metal vapor plasma is created in the cylindrical cathode of target material. The fabricated clusters, neutral and charged are expanded through an exit nozzle and collimated by an aerodynamic lens attached to the source. The clusters then flow through a secondary pumping stage bracketed by two skimmers and are size selected by an electrostatic quadrupole deflector for deposition. 

In a completely different approach to all the above-mentioned studies, von Helden and coworkers have combined ion trap technology with superfluid helium nanodroplets to measure spectra of cold biomolecular ions [59]. As illustrated schematically in Fig. 12, after producing gas-phase biomolecules via electrospray, they mass select them, bend them 90° with a static quadrupole deflector, and then trap them in a room temperature ion trap. A pulsed, helium droplet source produces... 

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