Which component forms the active sensing region of a semiconductor detector?

Which component forms the active sensing region of a semiconductor detector?

• A. Semiconductor crystal
• B. Display screen
• C. Photocathode
• D. Amplifier

Answer: (A)

The active sensing region is the semiconductor crystal, because this is where X-ray photons interact directly and generate charge carriers (electron-hole pairs). When the crystal is reverse-biased or otherwise biased to create a field, those charges are collected to produce a measurable electrical signal proportional to the energy deposited. The display screen is only for imaging output, not for sensing radiation. A photocathode emits electrons in vacuum-based detectors, not in solid-state semiconductor detectors. An amplifier boosts the signal after it’s created, but it does not serve as the region where the X-rays are first sensed. Thus, the semiconductor crystal itself is the active sensing area.

The active sensing region is the semiconductor crystal, because this is where X-ray photons interact directly and generate charge carriers (electron-hole pairs). When the crystal is reverse-biased or otherwise biased to create a field, those charges are collected to produce a measurable electrical signal proportional to the energy deposited. The display screen is only for imaging output, not for sensing radiation. A photocathode emits electrons in vacuum-based detectors, not in solid-state semiconductor detectors. An amplifier boosts the signal after it’s created, but it does not serve as the region where the X-rays are first sensed. Thus, the semiconductor crystal itself is the active sensing area.