(redirected from Quadropole)
Also found in: Dictionary.


A distribution of charge or magnetization which produces an electric or magnetic field equivalent to that produced by two electric or magnetic dipoles whose dipole moments have the same magnitude but point in opposite directions, and which are separated from each other by a small distance.
A mass distribution that has unequal components of the moment-of-inertia tensor along the three principal directions.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a system of charged particles whose total electric charge and electric dipole moment equal zero.

Figure 1. Examples of relative location of dipoles in a quadrupole

A quadrupole can be considered a set of two identical dipoles with the dipole moments equal in magnitude but opposite in direction and separated by a certain distance. At great distances R from the quadrupole, the field intensity of the quadrupole E decreases in inverse proportion to R to the fourth power (E∼ 1/R4). The relationship between E and the charges and their location is described in the general case by a set of five independent values that together constitute the quadrupole moment of the system. The quadrupole moment also determines the energy of a quadrupole in an external electric field. In the case described by Figure 1 the absolute value of the quadrupole moment is equal to 2ela, where e is the charge, 1 is the dimension of the dipoles, and a is the distance between the centers of the dipoles. A quadrupole is a second-order multipole.


Landau, L. D., and E. M. Lifshits. Teoriia polia, 5th ed. Moscow, 1967, § 41.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
While Rapiscan already markets the QXR1000 baggage screening system, which uses Quadropole Resonance (QR technology combined with dual-energy X-rays), the company's research subsidiary CXR Ltd has joined with the University of Manchester (UK) to develop a means of providing fast and accurate 3D X-ray images of airport luggage instead of the current one-dimensional view.
Thermo believes that the focus of the suit is its TSQ triple quadropole MS systems, for which US sales represent approximately 1% of its annual revenue.
Mass spectrometer analysis was conducted on an HP5890 GC with a quadropole HP5891A MS (Hewlett-Packard) operating in total ion monitoring mode (at 50 to 600 amu).
Quads Are the Most Popular Electrospray 26% Hybrid 3% Ion trap 19% Magnetic sector 16% Multiple MS 13% Quadropole 67% Time of flight 24% Other 10% Source: R&D Magazine Note: Table made from bar graph.
For the purpose of describing the quadropole shift, the orientation of the laboratory (quantization) axis with respect to the principal-axis frame is defined by the angles [Beta] and [Alpha].
The isomer shift, the quadropole splitting, the [Fe.sup.++]/[Fe.sup.+++] ratio, and the [Fe.sub.2][O.sub.3] content were determined and compared with results on local clays with known heat profiles.
For several samples, the identity of compounds was verified with a coupled gas chromatography mass spectrophotometer (GCMS, Hewlett-Packard quadropole type model 5890/5971, Julkunen-Tiitto et al.
The ion source and quadropole temperatures were set to 150[degrees]C and 103[degrees]C, respectively.
Thus, commercial instruments such as the linear ion trap quadropole (LTQ) mass spectrometer and the LTQ orbitrap hybrid mass spectrometer have contributed to greater sensitivity and accuracy in the detection of peptide masses in separated peaks.
The units, which are based on Quantum's quadropole resonance (QR) technology are the first QScan 500s to receive FAA approval.