What is a defining characteristic of surface barrier detectors?

Surface barrier detectors are designed to effectively detect and measure the energy of incoming alpha particles. This capability arises from their construction, which includes a semiconductor material that is sensitive to the high-energy particles emitted by radioactive decay, particularly alpha particles. When an alpha particle strikes the surface of the detector, it generates electron-hole pairs, allowing for the measurement of both the presence and the energy of the particle. This characteristic is crucial in various applications, including environmental monitoring and health physics, where understanding the energy of the detected radiation can inform about the radioactive material present and its potential risks.

In contrast, other options reflect characteristics that do not define surface barrier detectors. While surface barrier detectors can be used in different measurement contexts, their primary function revolves around the detection of alpha particles and does not limit their use to short-term measurements. They do not require liquid samples; instead, they're designed for solid-state detection directly at the surface. Furthermore, while surface barrier detectors are effective for high-energy particles like alpha particles, they are not specifically focused on or limited to beta particles alone. Therefore, the emphasis on their ability to record the energy of incoming alpha particles encapsulates their defining purpose in radiation detection.