Energy deposition is the transfer of energy from incident particles or radiation to a specified material region during a specified time. In a detector, it can produce ionization, excitation, scintillation or heat. The measured signal depends on how those channels are collected and calibrated.
An energetic charged particle may deposit only part of its energy while crossing a thin sensor. Secondary photons or particles can carry energy out of the sensitive volume, so incident energy and deposited energy need not coincide. Conversely, a sufficiently containing calorimeter aims to collect the full shower response. Separating energy deposition from readout response prevents an uncalibrated pulse height from being mistaken for a direct energy measurement.
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