Again, measuring the amount of light gives you an idea of how energetic the incoming X-ray was. And some detectors, called calorimeters, do a direct measurement of the heat produced in the material when the incoming X-ray is absorbed. Different Jobs A principal question with selecting a detector for a given application is to determine what you exactly want to measure. Finally, you want to try to capture as many X-rays as possible, and thus have a large detector surface area. An ideal detector produces excellent resolution for all three quantities, but in practice, detectors are generally optimized for one quantity and then have less accuracy in determining the remaining ones.
All detectors have to deal with background.
Usually, there is a hubbub of noise and conversation, and it's hard to hear what everyone is saying. However, if someone across the room says your name, you can generally pick it out from the noise. This is because your name is a clear signal, with a specific shape, while the overall noise is a somewhat homogeneous mess. Detecting X-ray signals over the background noise is a subtle art that is very important when doing analysis. Specific Detector Types Proportional counters are one of the most common X-ray detectors used by recent missions, although CCD chips are rapidly gaining popularity as the technology improves.