The pulse mixing method applied to the activity measurement of 85Sr

A very simple 4πβγ coincidence system which uses extendable dead-times and a common channel instead of a coincidence channel is described. All the major problems encountered in conventional systems are eliminated. An important feature of this system is its insensitivity to the delay between the beta and gamma pulses. This means that the activity measurement of a radio nuclide having a delayed state (1 μs) such as 85Sr is very simple. This was checked by the activity measurement of this radionuclide.