IM 203M™ Mobile Iodine Monitor

Compact, lightweight and movable, this monitor measures the gamma volumetric activity of radioactive iodine sampler.



  • Embedded 241Am source for energy spectrum stabilization against temperature changes and aging
  • 1024 channels spectrum analysis
  • Effluent trapping of both molecular and organic forms of iodine
  • Can be used as temporary bypass for IM 201S™ or IM 201L™ monitors to maintain full monitoring capability during maintenance


The IM 203M monitor forms part of the RAMSYS™ product line.

It has been developed to continuously measure the gamma volumetric activity of radioactive iodine sample, in both molecular and organic forms (methyl iodine), contained in air drawn from stacks, ventilation ducts or working areas.

A NaI scintillation detector faces the activated charcoal cartridge in which radioactive iodine is trapped. The proximity of the detector to the cartridge, enclose within a 4 π/2 cm (4 π/0.8 in) lead shielding, serves to optimize detection efficiency. A radioactive 241Am source built into the NaI crystal allows compensation of temperature and aging related drifts. The spectrometry capability, based on a 1024 channel spectrum analysis, allows radio iodine isotope localization.