(3) Interaction of high energy photons with matter - LUTH
(3) Interaction of high energy photons with matter - LUTH
(3) Interaction of high energy photons with matter - LUTH
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Electron-Positron Pair Production<br />
● High-<strong>energy</strong> <strong>photons</strong> can be converted into electron-positron pairs.<br />
● This process is not possible in free space, but only in the presence<br />
<strong>of</strong> an electromagnetic field (field <strong>of</strong> a nucleus, collision <strong>of</strong> two<br />
<strong>photons</strong>, magnetic field <strong>of</strong> the Earth...).<br />
● Important <strong>energy</strong> loss mechanism at the <strong>high</strong>est photon energies.<br />
● Basis <strong>of</strong> the electromagnetic cascade caused by -rays in the<br />
atmosphere (see Chapter 5).<br />
A. Zech, Instrumentation in High Energy Astrophysics<br />
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