Electrostatic Quadrupole

Figure 5. An isometric view of the new injection system, showing the dipole magnets B1 and B2, the electrostatic deflectors D1-D4, and the aperture plate A A. The positions of the electrostatic quadrupoles Q1 and Q2 are indicated also. The principal rays for beams of two different isotopes in the deflected up position are indicated by the solid lines, with the undeflected rays shown as...

Laser matrix time of flight Electrostatic quadrupole Time of flight Electrostatic-sector... 

PENNING TRAP A different approach to mass measurements was developed at Mainz. Thermal ions can be confined in a static homogenous magnetic field and a superimposed electrostatic quadrupole field. A measurement of the cyclotron frequency enables the measurement of the mass of the stored ion. A resolving 6 8 -7 -8... 

An electrostatic quadrupole moment is a second-rank tensor characterized by three components in its principal-axis system. Since the trace of the quadrupole moment tensor is equal to zero, and atomic nuclei have an axis of symmetry, there is only one independent principal value, the nuclear quadrupole moment, Q. This quadrupole moment interacts with the electrostatic field-gradient tensor arising from the charge distribution around the nucleus. This tensor is also traceless but it is not necessarily cylindrically symmetrical. It therefore needs in general to be characterized by two independent components. The three principal values of the field-gradient tensor are represented by the symbols qxx, qyy and qzz with the convention ... 

The electrostatic quadrupole term in this sum is that for which ( = 2, so that the quadrupole Hamiltonian is given by... 

Of (A - D), only (B) should exhibit a linear structure. It has in fact been confirmed that a molecular beam of Si02 generated at 2500 K is not deflected by an electrostatic quadrupole. Consequently Si02 must be linear 69 ... 

Figure 4. The electrostatic quadrupole triplet lens and target chamber used for micro PIXE showing the 30 sq mm Si(Li) X-ray detector and the absotber ladder at 135 the RBS detectors which are at 158 above and below the lens the Ge(Li) PIGE detector and collimator the electron flood gun and the movable zoom microscope used for focusing and alignment of the beam.

Moments of geometry Moments of inertia Electrostatic quadrupole moments Lipophilic quadrupole moments... 

In a study of the structure of monolayer films of carbon dioxide on graphite, Morishige [86] observed that carbon dioxide does not wet the graphite surface at temperatures below 104 K. It is likely that the electrostatic quadrupole inter-... 

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.

Finally, taking into account only the electrostatic quadrupole-quadmpole interactions, the ratio of the values of the critical temperature for the quantum case and that for the classical case were also derived. The ratio of the classical transition temperature to that of its (7=1) quantum analogue is found to be f without the crystal-field effects. This result could be derived for a quite general quadratic Hamiltonian of the type (2.1). However, it was assumed that the transition is continuous, and the reported ratio no longer holds for a first-order transition. It is suggested [141] that this result may be relevant to the N2 system. 

A prototype model for orientational ordering of electrostatic quadrupoles on a triangular net in a static crystal field was devised and systematically investigated based on mean-field, Landau, and spin-wave theory [21, 141] see Section II.A for an extensive discussion. 

For polar molecules with an electric dipole moment, Rabi spectrometers with electrostatic quadrupole deflection fields offer the possibility to detect rotationally inelastic collisions since the focusing and deflecting properties of the quadrupole field depend on the quantum state J, M) of a polar molecule. This technique is, however, restricted to molecules with a large electric dipole moment and to small values of the rotational quantum number J [1076]. 

Electrostatic quadrupole filters and quadru-pole ion traps... 

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. 

Synonyms Electrostatic quadrupole Quadrupole mass spectrometer Quantum Dot... 

Fig. 3.13. Construction details of the combination of a temperature variable 22-pole ion trap and a pulsed supersonic beam. Primary ions are produced in a storage ion source and mass selected in a quadrupole mass filter (from the bottom, not shown). After deflection in an electrostatic quadrupole bender the ions are injected into the trap (see Fig. 3.12). There the ions are confined in radial direction by the rf field and in axial direction with dc voltages applied to the entrance and exit electrodes (less than 100 mV). Buffer gas is used, usually He, for thermalizing the ions. From the left a skimmed molecular beam traverses the trap without colliding with the cold surfaces. For detection, the stored ions are extracted to the right, mass selected and counted via a Daly detector. A laser beam can be injected via the detector tract for state selective excitation of the trapped ions.

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