The PIN X-ray diode is a variation of the PIN photodiode. Types exists for X-ray, gamma and particle radiations. To use it as a radiation detector you can measure the voltage it gives out, the more charged particles that hits it the higher the voltage. Also it's resistance varies when particles impacts. This is similar to the PIN diode where the resistance varies by how much current that flows through it, but in the X-ray diode this depends on how much radiation it is subjected to.

This is caused by an effect similar to the avalanche photo diode; The ionizing effect of the particle impacts causes a release and a flow of electrons.

An array made of x-ray diodes can be used in x-ray and gamma cameras. These cameras have many uses in space- and medical research.