IMP, TU Darmstadt, Darmstadt, Germany
THM, Friedberg, Germany
Over the last few decades several types of Terahertz (THz) detectors have been developed to maturity, paving the way for various potential applications such as diagnostics of THz generation at particle accelerators. An important class are zero-biased Schottky diode THz detectors that are frequently applied at accelerator facilities [*] for operation at room temperature. Zero-biased Schottky diode THz detectors [**,***] are having lower noise compared to biased ones due to the absence of shot noise. Here we demonstrate the sensitivity of Schottky detectors using a commercial continuous wave photomixing THz system as source. Both, a commercially available as well as a research-grade compact quasi-optical detector with improved video bandwidth are compared from 0.05 to 1.2 THz in terms of sensitivity. At 1 THz, the research grade quasi optical detector shows 7 dB higher dynamic range than the commercial one.
[*] Preu, S.,et al.,DOI: 10.1109/TTHZ.2015.2482943
[**] Penirschke, A.,et al.,DOI: 10.1109/IRMMW-THz.2014.6956027
[***] Hoefle, M.,et al.,DOI: 10.1109/IRMMW-THz.2013.6665893
THM, Friedberg, Germany
TEMF, TU Darmstadt, Darmstadt, Germany
DESY, Hamburg, Germany
The all-optical synchronization system implemented in the European X-ray free-electron laser (EuXFEL) is to receive an upgrade. The modifications are intended to allow operation with consistently high accuracy in a 1 pC mode, which is required for various user experiments. The lower charges, e.g. a factor of 20, lead to a reduced signal strength at the pickups and thus to a decreased resolution. A significant potential for improvement has been identified in a modified pickup structure and transmission network, which provide the transient voltage signal to subsequent parts of the synchronization system. One solution for a broadband pickup structure with short signal paths, large active surfaces and minimum aperture diameter could be achieved by connecting rod-shaped pickups to a combination network on a printed circuit board, which will be mounted in the beamline. In this contribution the proposed design is introduced and analyzed by electromagnetic field simulations.