An automatic timer control unit for the Farmer dosemeter type 2502/3

The unit operates an electronic timer to measure the time taken to achieve a preset dose on a Farmer dosemeter type 2502/3 (Nuclear Enterprises Ltd). The device thus eliminates personal errors associated with the manual operation of stop watches or electronic timers (Twiss and Lewis 1979). The latter type of timer includes the Nuclear Enterprises type 2546 timer which is compatible with the type 2502/3 dosemeter but incapable of stopping automatically when a preset dose is achieved. The ease with which the correct operation of the device can be checked makes it ideal for all routine measurements, in particular, checks of the dosemeter performance using the strontium-90 check source.