TU Darmstadt, Darmstadt, Germany
The S-DALINAC is a superconducting electron accelerator operated at TU Darmstadt. It is running in recirculating operation since 1991. An upgrade done in the years 2015/2016 enables to use the S-DALINAC as an energy-recovery linac (ERL) [1]. The lattice is capable of a once- (up to 34 MeV) or twice-recirculating ERL operation (up to 68 MeV). For both modes dedicated beam dynamics simulations have been conducted. An important aspect is the effect of phase slippage and its influence on the quality of the decelerated beam. Furthermore, investigations regarding specialized diagnostic systems are currently ongoing. This is of great importance especially for the twice-recirculating ERL, where two beams of the same energy are transported through the same beam line. The commissioning of the different ERL modes started in 2017 and will be continued during upcoming beam times. This contribution will give an overview on the ERL modes at S-DALINAC. The beam dynamics simulations as well as diagnostics used will be discussed. Results and operational findings of the different ERL runs will be presented.
[1] N. Pietralla, Nuclear Physics News, Vol. 28, No. 2, (2018) 4.
TU Darmstadt, Darmstadt, Germany
The recirculating superconducting Darmstadt linear accelerator S-DALINAC [1] is one of the main research instruments at the institute for nuclear physics at the TU Darmstadt. It is operating in cw mode at beam currents of up to 20 uA with energies of up to 130 MeV using a thrice recirculating scheme. In 2010 the present digital low-level rf (LLRF) control system was set into operation. Since 2017 the S-DALINAC can be used as an energy recovery linac (ERL). The ERL mode is adjusted by shifting the phase of the beam by 180° in the second recirculation. The current setup of the LLRF control system is not optimized for the usage in an ERL operation. Therefore investigations in regard of the rf control performance have to be done. The first successful one turn ERL operation was set up in August 2017 where the rf control performance was investigated the first time in this new mode. In this talk the LLRF control system of the S-DALINAC is presented and its perfomance during an ERL operation is discussed.
*[1] N. Pietralla, Nucl. Phys. News 28 No. 2, 4 (2018).
TU Darmstadt, Darmstadt, Germany
The recirculating superconducting electron accelerator S-DALINAC [1] at TU Darmstadt is capable to run as a onefold or twofold Energy Recovery Linac (ERL) with a maximum energy of approximately 34 or 68 MeV in ERL mode, respectively. Since the maximum kinetic energy for the twofold ERL mode at injection is less than 8 MeV (v/c<0.9982) and since several multi-cell cavities designed for v/c=1 are used in the main accelerator, the electrons suffer from the effect of phase slippage. Therefore, beam dynamics simulations for the 6D phase space were performed in order to provide a sufficient beam guiding.
[1] N. Pietralla, Nuclear Physics News, Vol. 28, No. 2, 4 (2018).