TU Darmstadt, Darmstadt, Germany
IKP, Mainz, Germany
HIM, Mainz, Germany
The S-DALINAC is a thrice recirculating, superconducting linear electron accelerator at TU Darmstadt. It delivers electron beams in cw-mode with energies up to 130 MeV. The high-energy scraper system has been installed in its extraction beam line to reduce the energy spread and improve the energy stability of the beam for the experiments operated downstream. It comprises three scraper slits within a dispersion-conserving chicane consisting of four dipole magnets and eight quadrupole magnets. The primary scraper, located in a dispersive section, allows to improve and stabilize the energy spread. In addition energy fluctuations can be detected. Scraping of x- and y-halo is implemented in two positions enclosing the position of the primary scraper. We will present technical details and results of the first commissioning run of the recently installed system at the S DALINAC. Besides improving on the energy spread, it proved to be a valuable device to observe energy spread and energy fluctuations as well as to reduce background count rates next to the experimental areas.
TU Darmstadt, Darmstadt, Germany
GSI, Darmstadt, Germany
The beam quality monitoring of extracted beams from SIS18, transported to the HADES experiment, is of great importance to ensure high efficiency data recording. The main detector system used for this purpose is the Start-Veto system which consists of two diamond based sensors made of pcCVD and scCVD materials. Both sensors are equipped with a double-sided strip segmented metalization (300 µm width) which allows a precise position determination of the beam position. Those senors are able to deliver a time precision <100 ps and can handle rate capabilities up to 107 particles/channel. The read-out of the sensors is based on the TRB3 system [1]. Precise FPGA-TDCs (264 channels, <10 ps RMS) are implemented inside FPGAs. The TRB3 system serves as data acquisition system with scaler capability. Analysis and on-line visualization will be performed in DABC [2]. Having the precise time measurement and a precise position information of the incoming beam ions one can monitor important beam parameters namely the beam intensity, its position during extraction and the beam time structure. In this contribution the general read-out concept will be introduced.
[1] A. Neiser et al., TRB3: a 264 channel high precision TDC platform and its applications, 2013 JINST 8 C12043.
[2] dabc.gsi.de, 30.05.2018
TU Darmstadt, Darmstadt, Germany
KPH, Mainz, Germany
The S-DALINAC is a thrice-recirculating, superconducting linear electron accelerator at TU Darmstadt. It can provide beams of electrons with energies up to 130 MeV and currents of 20 µA. The accelerator performance was improved by an extension of the beam diagnostics, as this increases the reproducibility of the machine settings. Therefore, the installation of several beam profile measurement stations is planned, which should be operational down to a beam current of 100 nA, as this current is used for beam tuning. Combining these devices with a quadrupole scan also allows for emittance measurements. The beam profile measurements shall be done based on optical transition radiation (OTR), resulting from the penetration of relativistic electrons from vacuum into a metal target. The radiation can be detected using standard cameras that provide information on the two-dimensional particle distribution. This contribution will address the layout of the measurement stations and a first test measurement will be presented.