Hawking radiation and thin shells

The properties of quantized scalar and Dirac fields around a collapsing thin shell are discussed and the Hawking radiation exhibited. The radiation is seen to be a result of the collapse process which involves the emission of a pair of particles traveling on either side of the event horizon from the shell. The reaction back on the shell is discussed and it is shown that the radiation only reacts through the metric. The contributions to the stress-energy tensor associated with the radiation are exhibited.