The NIM 201K monitor forms part of the RAMSYS product line. It has been developed to monitor in real time the ambient dose equivalent rate. It provides operational dose rate in units of H*(10) derived from neutron fluence according to ICRU 57 recommendations. The helium-3 proportional counter (cylindrical tube) placed inside a polyethylene sphere facilitates detection of thermal and fast neutrons. Its large energy range, associated with modular design makes it efficient, reliable and very sensitive. It is used effectively in nuclear reactors, subcritical stacks, neutron generators and irradiators, and in accelerator facilities.