In the injector section of electron linacs, both internal space charge forces and wakefield effects influence the beam dynamics. So far, existing simulation approaches can not account for both effects simultaneously. To fill this gap, we have developed a computational method to account for both effects self-consistently*. It couples a space charge solver in the rest frame of the bunch with a wakefield solver by means of a scattered field formulation. The novelty of this approach is that it enables us to simulate the creation of wakefields throughout the emission and acceleration process. In our contribution, we present extensive studies of the coupled wakefield and space charge effects in a traveling wave electron gun under development at the Paul Scherrer Institute. Wakefields created by the multi-cell design and the transition to the beam pipe are accounted for. Hence, the respective influences of these causes for geometric wakefields on particle dynamics are compared, providing detailed insights into the coupling of wakefields on bunches at low energies. Specifically, uncorrelated energy spread and emittance are investigated which are of key interest for FEL operation.

The storage ring from the SLS is currently in the process of a significant upgrade to a new multi-bend achromat that aims to improve the performance of the machine by allowing it to deliver even brighter beams to the beamlines. The linear accelerator of the SLS is an ageing piece of infrastructure that needs to continue to run for the few decades to continue to feed SLS 2.0 reliably. In this work, we investigate potential upgrades to the linac with the aim of reducing the overall complexity of the system.

MeV ultrafast electron diffraction has become a new frontier for the study of molecular dynamics. With the temporal resolution of MeV-UED being limited by the electron bunch length at the target, electron sources used for this technique are becoming ever more intricate in the the push for shorter bunches length. However, moving to these complex setups makes them less feasible in a small-scale setting, such as universities, where keV-UED setups have become common place. In this paper, we use a novel travelling-wave RF photogun without any additional bunch compressor to generate ultra-short electron pulses whose lengths rival that of the most intricate magnetic or ballistic compression schemes. The broadband nature of the TW device allows for unique operation schemes that combines significant acceleration and compression all within the TW photogun. Such a device, when combined with state-of-the-art synchronization systems and lasers will be demonstrated to cross the so-called ‘50-fs time-resolution barrier’ and push towards the femtosecond regime.

An international collaboration between PSI and INFN-LNF has been undertaken with the aim of developing the next generation of high brightness electron sources. Through this collaboration, two unique high gradient RF photoguns that operate in the C-band frequency regime have been designed and realized. Concurrent to this, a new high power test stand at the Paul Scherrer Institut has been commissioned to test these novel devices. Here we report on the new test stand and the first results from the high-power testing of these devices.

In the injector section of electron linacs, both internal space charge forces and wakefield effects influence the beam dynamics. So far, existing simulation approaches can not account for both effects simultaneously. To fill this gap, we have developed a computational method to account for both effects self-consistently*. It couples a space charge solver in the rest frame of the bunch with a wakefield solver by means of a scattered field formulation. The novelty of this approach is that it enables us to simulate the creation of wakefields throughout the emission and acceleration process. In our contribution, we present extensive studies of the coupled wakefield and space charge effects in a traveling wave electron gun under development at the Paul Scherrer Institute. Wakefields created by the multi-cell design and the transition to the beam pipe are accounted for. Hence, the respective influences of these causes for geometric wakefields on particle dynamics are compared, providing detailed insights into the coupling of wakefields on bunches at low energies. Specifically, uncorrelated energy spread and emittance are investigated which are of key interest for FEL operation.

RF photo-gun are the electron beam sources of FELs or Compton facilities. They are key components and, presently, the RF technology mostly used for these devices is the S band (3 GHz) with typical cathode peak fields of 80-120 MV/m and repetition rates lower than 100-120 Hz. An innovative C-Band (5.712 GHz) RF gun aiming at reaching cathode peak field larger than 160 MV/m, with repetition rates exceeding the 400 Hz, has been designed, realized and high power tested in the context of the European I.FAST and INFN Commission V projects. It is a 2.5 cell standing wave cavity with a four-port mode launcher, designed to operate with short RF pulses (300 ns). Its realization is based on the new brazed-free technology developed and successfully tested at INFN. In the paper, after a short overview of the design and RF gun capabilities, we illustrate the realization procedure and the results of the high power RF tests that have been done at the high power C band test facility at PSI (Switzerland).