Model N23343
Markus® Plane-Parallel Ion Chamber
The Model N23343 Markus® plane-parallel ionization chamber is designed
specifically for the dosimetry of electrons with energies above 100keV, according to the Bragg-Gray
principle. It is suitable for measurements in either solid or water phantoms.
The chamber consists of a cylindrical acrylic body whose measuring volume is flush to the
surface to permit dose measurements at very small depths. The entrance window is made of
polyethylene (2.5mg/cm2) with a graphite conductive coating.
The ion collector is graphite-coated acrylic and is provided with a guard ring that rests at ground
potential. The low collector volume minimizes polarity effects and electrostatic charge.
The chamber is vented to the atmosphere and equilibrates through the aperture in the window ring.
The design provides for energy independence and high spatial resolution, and minimizes polarity
and perturbation effects.
The Model N23343 includes a 0.87mm thick acrylic protective cap for use in a water phantom,
a spacer ring for use in a solid phantom and an acrylic build-up disc. For measurements in water
phantoms, equilibration may be achieved by taking the protective cap off briefly just before the
measurement is taken.