The construction of an advanced Light Source like SwissFEL required a great deal of engineering creativity. Many of the issues to be addressed during this phase demanded completely new solutions. The goal of building a compact and not all too costly Free Electron Laser has been spurring a host of innovations by both scientists and contractors.
The SwissFEL baseline design aims to produce FEL pulses covering the wavelength range 1 Å to 70 Å (0.1–7 nm) with a compact and economic design, which is affordable on the scale of a national laboratory. The overall cost of a linear accelerator depends strongly on the final beam energy, therefore, a key design goal is to minimize the required electron beam energy for a given radiation wavelength. With the dependence of photon beam wavelength on electron beam energy and undulator period discussed in the previous section,this implies the use of an undulator with a short period length and a rather low K value. The emittance achievable with the injector puts another lower limit on the beam energy. Both constraints are most stringent for the shortest lasing wavelength. Based on these factors, and considering the best performance achievable with leading-edge undulator and electron injector technology, the following parameters where chosen to achieve lasing with the SwissFEL at 1 Å wavelength:
|Basic FEL parameters||Aramis beamline||Athos beamline|
|Effective saturation power||~ 2.0GW||4.4-6.5GW|