What is the radiation-sensitive portion of a semiconductor detector composed of?

The radiation-sensitive portion of a semiconductor detector is indeed composed of a type of material that allows for the efficient detection of ionizing radiation. In the context of semiconductor detectors, the correct material is typically an electron-emissive crystal. This allows for the generation of electron-hole pairs when radiation interacts with the material, facilitating the conversion of radiation energy into measurable electrical signals.

Semiconductor detectors utilize materials like silicon or germanium, which are intrinsic semiconductors that can be doped to create p-type and n-type regions. When radiation passes through the semiconductor, it excites electrons, which then move through the crystal lattice. The ability of these materials to detect radiation stems from their electronic properties, specifically how they respond to radiation by allowing charge carriers (electrons and holes) to move and create a measurable signal.

This functionality is crucial for the operation of radiation detection devices, as the interaction of ionizing radiation with the detector's material is what leads to the detection and measurement of radiation levels. Understanding this principle is fundamental to the design and use of semiconductor detection technology in applications related to radiation monitoring and safety.