X-ray diodes operate by absorbing photons or charged particles. In current mode the output current is measured directly from the detector.
Current mode is used typically when event rates are very high.
In current mode applications the output current is proportional to the intensity of the incident radiation with high accuracy. In pulse mode the single hits are transformed into pulses and then recorded. X-ray diodes and photodiodes have also two different modes of operation depending on the bias voltage supplied to the detector. In photoconductive mode the diode is operated with high bias voltage. This mode is used for example in X-ray exposure and dose control applications.