A CMA consists of two concentric metal cylinders arranged such that their axes are coincident. Different voltages are placed on each cylinder such that there is an electric field between the two cylinders. Electrons are injected from a point on the axis into the gap between the two cylinders. If the electrons are travelling very fast, they will impinge on the outer cylinder. If they are travelling very slowly, they will be attracted to the inner cylinder. Hence only electrons in a narrow energy region (called the pass energy) succeed in getting all the way along the cylinders to the detector. The resolution is improved by aperatures within the analyser. Commercial CMA's are generally based on a "double pass" design where electrons travel through the analyser in a figure-of-eight path (see the schematic diagram, 8k). This second stage of filtering is intended to reduce spurious background signal due to secondary electrons generated within the analyser.

The CMA can be operated in two modes, retarding and non-retarding(see also RFA - Retarding Field Analyser). In retarding mode the energy resolution is increased by slowing the electrons before they enter the analyser using two hemispherical grids at its snout. The first of these is held at the same potential as the sample whilst the second is set to a few eV less than the energy of the electrons so that they enter the channeltron at a constant energy. This energy, the pass energy, is typically 5 or 10 eV. This method is used rather than the addition of an electrostatic lens like that on the CHA because the analyser acceptance angle for a CMA is a range of approx. 6° about a mean of 42.3° from the axis at all azimuthal angles, a geometry incompatible with conventional electron lenses. The energy resolution is generally 2% of the pass energy, which can be varied by the user. Retarding mode is used where fine resolution is desired but the number of counts is generally restricted, because retarding mode gives better luminosity as a function of resolution than that produced by reducing the size of the aperatures that the electrons pass through within the analyser.

In non-retarding mode the electrons pass through the analyser with their initial kinetic energy and the energy range is swept by varying the potential on the outer cylinder. The resolution is then approximately 0.6% of the electron energy. This mode is used for AES because the electrons are coming from an excitation area that is small compared with the imaged area and would be scattered by irregularities in the terminal electric field of the grid if retarding mode were used, resulting in reduced transmission. To improve the resolution in non-retarding mode the size of the internal apertures is reduced. This results in a loss of counts although this is generally not a problem in AES.

This design of analyser, unlike the CHA, is particularly sensitive to the distance between it and the sample. It must be positioned at the correct focal distance using an external drive that moves the whole analyser in and out. Despite this the CMA has the advantage of a far higher solid angle of acceptance, which can be up to 100 times greater than that of a CHA. Although this increase is achieved at the expense of the ability to detect angle resolved features. The concentric cylinder design also means that an electron gun can be accomodated within the central cylinder (see diagram) to provide an excitation source for Auger Electron Spectroscopy, (AES), or Electron Energy Loss spectroscopy, (EELS).