When the RAMs and CAMs aerosol monitors are provided with a gamma head, they are able to detect elemental iodine, attached to particles, but are practically insensitive to gaseous radioactive iodine. This can be measured by RIM models used as stand-alone monitors or as monitoring units coupled to the aerosol equipment. The RIM monitors are real time, continuous measuring devices based on the gamma spectrometry method with NaI(TI) detector.
The RIM-01 is the single cartridge standard unit with manual replacement while the RIM-14 is the multiple (14) cartridge special unit with automatic replacement. In normal condition the autonomy of the RIM-14 is about 3-4 months, thus comparable to the one of the RAM-31. Both the iodine monitoring heads are usually controlled by a dedicated processor.
Iodine is sampled with a constant flow rate on a 2 1/4" D x 1" H cartridge, plastic type, placed in front of the gamma detector. The measuring head is enclosed in a lead shield 5 cm thick. Together with the cartridge replacing assembly (in case of the RIM-14 automatic model), due to its weight, it is placed at the bottom of a standard 19" rack cabinet.
In the RIM-14, the cartridge is automatically replaced at software selectable intervals, otherwise in the RIM-01 the cartridge is manually replaced by means of a simple 'holder/slide'. Sampling time and measuring cycle are programmable and can be automatically changed according to the measurement range if needed. All parts of the measuring chamber around the cartridge are realised in stainless-steel for easy decontamination.