Separation of gamma and hadron initiated air showers with energies between 20 and 500 TeV.
Abstract
The discrimination between air showers initiated by γ rays and by hadrons is one of the fundamental problems in experimental cosmic-ray physics. The physics of this 'γ/hadron separation' is discussed in this paper. The authors restrict themselves to the energy range from about 20 to 500 TeV, and take only the information contained in the lateral Čerenkov light distribution and the number of electrons at the detector level into consideration. An understanding of the differences between air showers generated by γ rays and those due to hadrons leads to formulate suitable observables for the separation process. Angle integrating Čerenkov arrays (AICA) offer a promising new approach to ground-based γ-ray astronomy in the energy region from about 20 to 500 TeV. As an example the authors present one method for γ/hadron separation in AICAs called "LES". It is based on the simultaneous determination of the shower size and some characteristic parameters of the lateral distribution of the Čerenkov light. The potential inherent within this technique is demonstrated in quantitative detail for the existing "AIROBICC" AICA. They also propose an objective measure of the intrinsic sensitivity of a detection scheme in ground-based γ-ray astronomy, the "reduced quality factor". It is shown that AICAs may reach a sensitivity to γ-ray point sources in the high VHE range similar to that of the Čerenkov-telescope imaging technique in the low VHE region.
- Publication:
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Separation of gamma and hadron initiated air showers with energies between 20 and 500 TeV
- Pub Date:
- April 1995
- Bibcode:
- 1995sghi.book.....A