Spectral filtering with diffractive reflection gratings for fast superconducting detectors in the THz frequency range

In this work we describe the design process of a grating spectrometer with fast superconducting THz detectors based on Niobiumnitride. The main application is the use as a diagnostic tool for accelerator-based sources of THz radiation like synchrotrons, where interactions of the electron bunches in storage ring lead to fluctuations in spectrum and intensity of the emitted radiation. Guidelines for the design of the two main parts, grating and detector design, are given. Here, a blazed reflection grating for a frequency range of 1 THz to 5 THz has been developed and successfully fabricated in a high-precision milling process out of brass. Also three different planar antenna designs (double-slot, annular slot and log-per spiral) in combination with quasioptical bandpass filters for the THz range have been simulated and evaluated for best spectral resolution and power coupling. Finally, we have verified grating performance for pulsed THz radiation of 1 THz in an experiment conducted at the synchrotron light source of the KIT. Excellent agreement of the grating performance to the simulations has been found

DYSMON II. Dynamik in Sulfid- und Methanbiotopen der Ost- und Nordsee. Abschlussbericht. Bd. 1

Working from the results of DYSMON I the purpose of the DYSMON II project was to examine the emergence of sulphidic, low-oxygen environments and microorganismic and faunal responses to this. The focus was on determining the resilience of ecologically important organisms after sudden drops in sulphide concentration and tolerance of oxygen deficiency and sulphide. Whereas in DYSMON I samples had largely been taken from natural sites, DYSMON II made use of ecological manipulation experiments (tarpaulin covers) so as to simulate natural covering with algae. A real-life experiment took place at Hiddensee in May 1995 when the effects of a very thick layer of algae were examined. This natural occurrence of an anoxic, sulphidic environment permitted a comparison with the experimentally induced anoxia in the sediments. (orig.)Das Projekt DYSMON II untersuchte, aufbauend auf den Ergebnissen von DYSMON I, die Entstehung sulfidischer, sauerstoffarmer Lebensbereiche und die darauf folgende Reaktion von Mikroorganismen und Fauna. Schwerpunkte lagen dabei auf der Ermittlung der Resilienz oekologisch wichtiger Organismen nach 'Sulfideinbruechen' und auf Untersuchungen zur Toleranz gegenueber Sauerstoffmangel und Sulfid. Waren waehrend DYSMON I ueberwiegend natuerliche Standorte beprobt worden, so konnten waehrend DYSMON II oekologische Manipulationsexperimente (Planenabdeckung) vorgenommen werden, um natuerliche Algenabdeckungen zu simulieren. Als Realexperiment gelang es, im Mai 1995 am Standort Hiddensee die Auswirkung einer sehr dicken Algenschicht zu erfassen. Diese natuerliche Entstehung von anoxischen, sulfidischen Bedingungen erlaubte einen Vergleich mit der experimentell induzierten Anoxie in den Sedimenten. (orig.)Available from TIB Hannover: F97B1291 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Beam-based commissioning of a novel X-band transverse deflection structure with variable polarization

Longitudinal electron-beam diagnostics play a critical role in the operation and control of x-ray free-electron lasers, which rely on parameters such as the current profile, the longitudinal phase space, or the slice emittance of the particle distribution. On the one hand, the femtosecond-scale electron bunches produced at these facilities impose stringent requirements on the resolution achievable with the diagnostics. On the other, research and development of novel accelerator technologies such as beam-driven plasma-wakefield accelerators (PWFA) demand unprecedented capabilities to resolve the centroid offsets in the full transverse plane along the longitudinal bunch coordinate. We present the beam-based commissioning of an advanced X-band transverse-deflection rf structure (TDS) system with the new feature of providing variable polarization of the deflecting force: the PolariX-TDS. By means of a comprehensive campaign of measurements conducted with the prototype, key parameters of the rf performance of the system are validated and a phase-space characterization of an electron bunch is accomplished with a time resolution of 3.3 fs. Furthermore, an analysis of second-order effects induced on the bunch from its passage through the PolariX-TDS is presented

Beam-based commissioning of a novel X-band transverse deflection structure with variable polarization

Longitudinal electron-beam diagnostics play a critical role in the operation and control of x-ray free-electron lasers, which rely on parameters such as the current profile, the longitudinal phase space, or the slice emittance of the particle distribution. On the one hand, the femtosecond-scale electron bunches produced at these facilities impose stringent requirements on the resolution achievable with the diagnostics. On the other, research and development of novel accelerator technologies such as beam-driven plasma-wakefield accelerators (PWFA) demand unprecedented capabilities to resolve the centroid offsets in the full transverse plane along the longitudinal bunch coordinate. We present the beam-based commissioning of an advanced X-band transverse-deflection rf structure (TDS) system with the new feature of providing variable polarization of the deflecting force: the PolariX-TDS. By means of a comprehensive campaign of measurements conducted with the prototype, key parameters of the rf performance of the system are validated and a phase-space characterization of an electron bunch is accomplished with a time resolution of 3.3 fs. Furthermore, an analysis of second-order effects induced on the bunch from its passage through the PolariX-TDS is presented

Effective intrahepatic CD8+ T-cell immune responses are induced by low but not high numbers of antigen-expressing hepatocytes.

Liver infections with hepatotropic viruses, such as hepatitis B virus and hepatitis C virus are accompanied by viral persistence and immune failure. CD8+ T cells are crucial mediators of the intrahepatic antiviral immune response. Chronic infections of the liver and other organs correlate with T-cell exhaustion. It was previously suggested that high antigen load could result in T-cell exhaustion. We aimed at elucidating the impact of different intrahepatic antigen loads on the quality of CD8+ T-cell-mediated immunity by employing an infection-free transgenic mouse model expressing ovalbumin (Ova) as the target antigen. Adoptive transfer of OT-I cells induced a transient intrahepatic immune response toward both high and low Ova levels. However, antigen clearance was achieved only in mice expressing low antigen levels. In contrast, T cells exposed to high antigen levels underwent exhaustion and became depleted, causing antigen persistence. Moreover, when functional T cells were exposed to high intrahepatic antigen levels, a complete transition toward exhaustion was observed. Thus, this study shows that the antigen expression level in the liver correlates inversely with T-cell immunity in vivo and governs the efficiency of immune responses upon antigen presentation

Measurement of jet production cross sections in deep-inelastic ep scattering at HERA (vol 77, 215, 2017)

The measurement of the jet cross sections by the H1 collaboration had been compared to various predictions including the next-to-next-to-leading order (NNLO) QCD calculations which are corrected in this erratum for an implementation error in one of the components of the NNLO calculations. The jet data and the other predictions remain unchanged. Eight figures, one table and conclusions are adapted accordingly, exhibiting even better agreement between the corrected NNLO predictions and the jet data