CAIN normally produces macro-photons such that the expected number of macro-photons per macro-electron is equal to the expected number of real photons per real electron. In some cases, however, too many macro-photons are created causing the memory overflow, or the statistics is too poor due to a small number of macro-photons. To solve this problem, a variable WENHANCEMENT= is introduced in the CFQED command.
When , more macro-photons are created. They have the weight smaller than that of the parent electron/positron by the factor 1/. However, the recoil of electron/positron is taken into account only with the probability 1/ so that their statistical property does not depend on .
When , the event generation goes the same as in the case =1, but the final photons are stored in the memory only with the probability . The recoil of electron/positron is taken into acount regardless the photon is stored or not.
Thus, if there is no bug, does not cause any physical change.