Internal Reports

A new little inexpensive real-time Gamma-Dosimeter is presented, which can monitor the gamma dose rate very acurately in the range of 0 – 2 mSv/d even for the pulsed time structure of the XFEL operation, and which can be readout remotely via a conventional USB connection. It is proposed to measure the dose and dose rates inside the electronic racks installed in the XFEL main linac tunnel. [...]

Barely two weeks after the European XFEL opened its doors to users, the first user experiment was performedby a DESY-led international team of over 120 researchers. The European XFEL is the first hard X-ray FEL in the world capable of producing femtosecond pulses at a megahertz repetition rate. [...]

Das DESY-Direktorium hat sich die von der HGF beschlossenen Regeln zur Sicherung guter wissenschaftlicher Praxis zu Eigen gemacht und auf dieser Grundlage in Abstimmung mit der DFG eine Kommission eingesetzt, die Empfehlungen zur Umsetzung dieser Regeln bei DESY vorgelegt hat. Auf dieser Grundlage sind die nachfolgenden Regeln aufgestellt worden, sie wurden im Wissenschaftlichen Ausschuss auf seiner Sitzung vom 14.11.2006 und vom Wissenschaftlichen Rat auf seiner Sitzung vom 27.10.2006 verabschiedet. [...]

The directorate of DESY has adopted the rules decided upon by the HGF [Helmholtz Association of German Research Centers] for ensuring good scientific practice and, on that basis, has set up a commission in coordination with the DFG [German Research Foundation], which commission has proposed recommendations for implementing these rules at DESY. Based on these recommendations, the following rules have been established, after adoption by the Scientific Committee at its meeting of November 14, 2006, and the Scientific Council at its meeting of October 27, 2006. [...]

This report summarizes vacuum system related calculations and simulations that are performed with respect to a conceptional design of PETRA IV. With assuming simple vacuumchamber geometries comparable to the design approach at MAX IV it addresses several key aspects of a conceptional design including the synchrotron radiation induced power load on vacuum chambers and other specific components, outgassing from photon stimulated desorption, pressure distributions, conditioning behavior and the saturation of dumping elements. [...]

Measurements of the top quark polarization and top quark pair ($\mathrm{t \bar t}$) spin correlations are presented using events containing two leptons produced in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13~\mathrm{TeV}$. The data were recorded by the CMS experiment at the CERN LHC in 2016 and correspond to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. [...]