Befestigungen der Bronze- und Eisenzeit zwischen Marburg und Uppsala

Dieser Beitrag schafft mit einer Übersicht zu bronze- und eisenzeitlichen Befestigungsanlagen im nördlichen Mittel- und im südlichen Nordeuropa die Grundlage für das Verständnis der metallzeitlichen Mehrfachburgen. Befestigungsanlagen werden hierbei definiert als Ein- oder Abgrenzung eines Gebietes mit Wällen, Gräben, Palisaden oder ähnlichen Anlagen. Die Forschungsgeschichte wird für die einzelnen Regionen dargestellt. Ein Schwerpunkt liegt auf der Chronologie, die mit Zusammenstellungen von Radiokarbondaten für die einzelnen Gebiete auf eine vergleichbare Grundlage gestellt wird. Es folgte eine Übersicht der Klassifikation der Befestigungsanlagen. Eine Karte und eine Liste von 403 Befestigungsanlagen im Arbeitsgebiet runden den Beitrag ab.This paper is an introduction to the concept of multiple fortifications, with an overview of Bronze and Iron Age fortifications in northern Central Europe and southern North Europe. Fortifications are understood as enclosures or delimitations marked with dikes, ditches, palisades, or similar constructions. The history of research into these fortifications is summarized, with a focus on chronology. The classification of fortified sites is also discussed. Lists of sites, radiocarbon dates, and a map of 403 fortifications are included in the text

bERLinPro Booster Cavity Design, Fabrication and Test Plans

The bERLinPro project, a 100 mA, 50 MeV superconducting RF SRF Energy Recovery Linac ERL is under construction at Helmholtz Zentrum Berlin for the purpose of studying the technical challenges and physics of operating a high current, c.w., 1.3 GHz ERL. This machine will utilize three unique SRF cryomodules for the injector, booster and linac module respectively. The booster cryomodule will contain three 2 cell SRF cavities, based on the original design by Cornell University, and will be equipped with twin 115 kW RF power couplers in order to provide the appropriate acceleration to the high current electron beam. This paper will review the status of the fabrication of the 4 booster cavities that have been built for this project by Jefferson Laboratory and look at the challenges presented by the incorporation of fundamental power couplers capable of delivering 115 kW. The test plan for the cavities and couplers will be given along with a brief overview of the cryomodule desig

Structural and RF properties of niobium films deposited onto annealed niobium resonators

Studies have been performed on the properties of niobium thin films sputtered onto solid niobium TM010 resonators at 1.5 GHz. The purpose of the work is to study the behaviour of the film's RF and str uctural properties as a function of heat treatment temperature in order to determine if and at what treatment temperature the properties of the films merge with those of the bulk. Niobium resonators h ave been heat treated at temperatures up to 1100°C in a vacuum furnace inside a niobium box surrounded by a titanium gettering protection. Subsequently, they have been sputter coated with a niobium fi lm. Following RF measurements of the coated resonators, the cavities have undergone heat treatments as described above at 800°C, 900°C, 1000°C and 1100°C, each time followed by RF measurements. Before heat treatment, the RF response of the film was similar to that of a film coated on a copper substrate. A marked transition towards bulk-like RF behaviour was observed after the 900°C treatment. The c hanges include a sharp variation of the BCS resistance and of the sensitivity to externally applied magnetic field, quantities believed to be closely linked to the amount and nature of defects in the coating

First Horizontal Test Results of the HZB SRF Photoinjector for bERLinPro

The bERLinPro project, a small superconducting RF SRF c.w. energy recovery linac ERL is being built at Helmholtz Zentrum Berlin in order to develop the technology required for operation of a high current, 100 mA, 50 MeV ERL. The electron source for the accelerator is a 1.4 cell SRF photoinjector fitted with a multi alkali photocathode. As part of the HZB photoinjector development program three different SRF photoinjectors will be fabricated and tested. The photoinjector described herein is the second cavity that has been fabricated, and the first photoinjector designed for use with a multi alkali photocathode. The photoinjector has been built and tested at JLab and subsequently shipped to HZB for testing in the horizontal test cryostat HoBiCaT prior to installation in the photoinjector cryomodule. This cryomodule will be used to measure the photocathode operation in a dedicated experiment called GunLab, the precursor to installation in the bERLinPro hall. This paper will report on the final results of the cavity installed in the helium vessel in the vertical testing dewar at Jefferson Lab as well as the first horizontal test in HoBiCa