An ion implantation system, having a temperature controlled ion source chamber is disclosed. The temperature of the ion source chamber is regulated by disposing a heat sink in proximity to the ion source chamber. A gas fillable chamber is disposed between and in physical communication with both the ion source chamber and the heat sink. By controlling the amount of gas, i.e. the gas pressure, within the gas fillable chamber, the coefficient of heat transfer can be manipulated. This allows the temperature of the ion source chamber to be controlled through the application or removal of gas from the gas fillable chamber. This independent temperature control decouples the power used to heat the ion generator from the ion species that are ultimately generated.