Application of an emittance adapter to increase photon flux density on a synchrotron radiation beam line

The application of the Chao-Raimondi emittance adapter to the SOLEIL storage ring is studied theoretically in terms of linear and nonlinear beam dynamics. This unique scheme recently proposed elsewhere using a pair of emittance adapters and a solenoid in between them allows a local conversion of an electron beam in a third generation light source to an ultralow emittance beam of the fourth generation. The study of potential benefits of the resultant synchrotron radiation is of crucial importance. Electron beam properties and magnetic fields inside the undulator solenoid are treated as inputs of the investigations. Characteristics of photon beams emitted by a round and small electron beam in an undulator are studied in detail on the basis of the near-field wave propagation method. The photon flux density gain, which is a figure of merit along with transverse coherence, is evaluated at the sample of two hard and soft x-ray beam lines existing at SOLEIL.