C. Burandt

Status and recent developments at the polarized-electron injector of the superconducting Darmstadt electron linear accelerator S-DALINAC

At the superconducting Darmstadt electron linac a 100 keV source of polarized electrons has been installed. Major components had been tested prior to installation at an offline teststand. Commissioning of the new source at the S-DALINAC will take place early in 2011. We report on the performance of the teststand, simulations, developments on the laser systems, new radio-frequency components for the S-DALINAC injector, and the status of the implementation of the source.

First ERL Operation of S-DALINAC and Commissioning of a Path Length Adjustment System

The S-DALINAC is a thrice-recirculating electron accelerator, capable of being operated in energy-recovery linac (ERL) mode. The change between conventional, accelerating operation and ERL mode is done by changing the distance traveled by the bunches in the second recirculation beam line. This distance is increased or decreased by moving dedicated magnets on a rail system. These so called pathlength adjustment systems exist in all recirculation beam lines but only the stroke in the second recirculation beam line enables a phase shift of up to 360° of the RF phase. After having proven the functionality of the new systems the once-recirculating ERL operation was demonstrated successfully in August 2017. This contribution will introduce the path-length adjustment systems and present the commissioning of them. Results of the operation of the first ERL in Germany will be discussed.

ERL Mode of S-DALINAC: Design and Status

Recently, the S-DALINAC was extended by an additional recirculation beam line to a thrice-recirculating linear accelerator. This upgrade enables an increase of the maximum achievable energy close to its design value of 130 MeV as well as an operation as an ERL. The new beam line features a path-length adjustment system which is capable of changing the phase of the beam by a full RF phase and, thus, allowing to shift the timing of the electron bunches to the decelerating phase. The project comprises different aspects concerning the design (magnets, beam dynamics, lattice, etc.) and the construction work including the alignment done at the accelerator. This contribution presents a rough overview on the design, installation and status.

A High-Energy-Scrapersystem for the S-DALINAC Extraction - Design and Installation

The superconducting Darmstadt linear electron accelerator (S-DALINAC) of the Institute for Nuclear Physics at Technische Universität Darmstadt delivers electron beams in cw-mode with energies up to 130 MeV. The accelerator consists of a 7.5 MeV injector and a 30 MeV main linac where superconducting 3 GHz cavities are operated at a temperature of 2 K. With three recirculation beam lines the main linac can be used up to four times. To reduce energy spread and improve the energy stability of the beam a new scrapersystem has been developed and installed. It changes the extraction beam line into a dispersion-conserving chicane consisting of four dipole magnets and three scrapers. The system includes scraping of xand y-halo at two positions as well as improving and stabilizing energy spread on a dispersive part.