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Energy Resolution in Calorimeters

  The ultimate limit for the energy resolution of a calorimeter is determined by fluctuations inherent in the development of showers, and by instrumental and calibration limits. The basic phenomena in showers are statistical processes, hence the intrinsic limiting accuracy, expressed as a fraction of total energy, improves with increasing energy as:

Over much of the useful range of calorimeters, this term dominates energy resolution.

There are other contributions than statistics, though: a second component is due to instrumental effects, being rather energy-independent (noise, pedestal); its relative contribution decreaseswith E:

This component may limit the low-energy performance of calorimeters.

A third component is due to calibration errors, non-uniformities and non-linearities in photomultipliers, proportional counters, ADC's, etc. This contribution is energy-independent:

This component sets the limit for the performance at very high energies.

The two types of showers have markedly different characteristics:

More reading can be found e.g. in [Gordon95], [Fabjan91], [Wigmans91a], [Brau90].


next up previous contents index
Next: Equations of Motion Up: No Title Previous: Energy Loss

Rudolf K. Bock, 9 April 1998