We discuss the radiation generated by positrons channeling in a crystalline undulator. The undulator is produced by periodically bending a single crystal with an amplitude much larger than the interplanar spacing. Different approaches for bending the crystal are described and the restrictions on the parameters of the bending are discussed. We also present numeric calculations of the spontaneous...

We present a method for generating femtosecond duration x-ray pulses using a single-pass free-electron laser (FEL). This method uses an energy-chirped electron beam to produce a frequency-chirped x-ray pulse through selfamplified spontaneous emission (SASE). After the undulator we consider passing the radiation through a monochromator. The frequency is correlated to the longitudinal position wi...

There is a growing interest in producing intense, coherent x-ray radiation with an adjustable and arbitrary polarization state. In this paper, we study the crossed undulator scheme for rapid polarization control in a self-amplified spontaneous emission (SASE) free electron laser (FEL). Because a SASE source is a temporally chaotic light, we perform a statistical analysis on the state of polariz...

A new type deflector of a charged particle beam based on pyroelectric crystals is proposed and demonstrated experimentally. The transverse electric field arises in the gap between two pyroelectric crystals in vacuum because of the pyroelectric effect appearing when a temperature gradient is applied to both crystals. In a proof-of-principle experiment, we demonstrated deflection of a low-energy ...

Superconducting in-vacuo undulators reach higher fields at lower periods compared to permanent magnet undulators. After the first successful tests of such an undulator with beam in Mainz [1] and an analysis of the emitted radiation a team consisting of members of ACCEL and the Research Center Karlsruhe began to build a superconducting undulator for the 2.5 GeV storage ring ANKA. In this paper (...

A new and simple method to generate X-ray free-electron-laser radiation with unprecedented spectral bandwidth above the 10% level is presented. The broad bandwidth is achieved by sending a transversely tilted beam through a transverse-gradient undulator. The extent of the bandwidth can easily be controlled by variation of the beam tilt or the undulator gradient. Numerical simulations confirm th...

The main features of radiation by relativistic electrons are well approximated in the Weizsäcker-Williams method of virtual quanta. This method is best known for its application to radiation during elementary particle collisions, but is equally useful in describing “classical” radiation emitted during the interaction of a single relativistic electron with an extended system, such as synchrotron...

This paper discusses the undulator radiation emitted by high-energy positrons during planar channeling in periodically bent crystals. We demonstrate that the construction of the undulator for positrons with energies of 10 GeV and above is only possible if one takes into account the radiative energy losses. The frequency of the undulator radiation depends on the energy of the particle. Thus the ...

Electron beams are strongly microbunched near the high-gain free-electron laser (FEL) saturation with a rich harmonic content in the beam current. While the coherent harmonic emission is possible in a planar undulator, the thirdharmonic radiation typically dominates with about 1% of the fundamental power at saturation. In this paper, we discuss the second-harmonic radiation in the Linac Coheren...