A dosimeter system is required to measure absorbed cumulative gamma radiation doseduring active service, soldiers have to cope upwith various radiological situations like nuclear explosions or missions in contaminated zones. The monitoring of total dose exposure to the soldier is required to be monitor at regular intervals that how long he can remain in the contaminated fields. For this purpose, a sensor is required which can detect the cumulative gamma radiation dose for subsequent medical treatments of soldiers.The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) sensor is an attractive solution for measurement of cumulative gamma radiation dose. Because, it's small in size (order of mm size) & weight, low cost, high input impedance, real-time or delayed direct read-out, information retention with small fading, non-destructivereadout, easily compatible with other electronic interfaces etc., over other commonly used solid state detectors include Thermo-Luminescent Dosimeter (TLD).In this thesis,dosimetersystem is proposed with programmable constant current source. The programmable current sourcecircuitis developed using current source IC (programmable from 1μA to 10mA), digital potentiometer IC in rheostat mode (1kΩ resistance with 256 steps), 10-bit A/D Converter and 8-bit PIC microcontroller.Initially, current source circuit is simulated and tested with analog resistors on some unexposed and exposed MOSFET sensorsat IZTCcurrents in the range of 200μA-400μA. Then, this circuit is madeprogrammable by using rheostat and microcontrollerand achieved constant current. Finally, by using this circuit, six numbers of MOSFET sensorsare exposed under gamma radiation environment and measured shift in threshold voltage and calculated the sensitivity of each device and displayed the dose data. Subsequently, Keithley's current source is utilized to measure the voltages of the same exposed sensors by measurements performed at IZTCcurrents. Also, the evaluation is performed on sensitivity parameter between proposed programmable current source circuit andKeithley's current source. The results are found to be closely matchingand percentage change in radiation sensitivity is less than 8%.