Annotated record of the detailed examination of Mn deposits from the 1993 R/V Sonne SO-84 expedition in the Atlantic Ocean

The SO-84 cruise from Las Palmas to Cape Town studied the underwater volcanism associated with the St Helena hotspot. Wide-spaced grid mapping of a region south and west of St Helena island identified three previously unknown hotspot volcanoes (which we named Josephine 16°27'S-9°W, Jade 16°13'S-7°46'W and Benjamin 16°12'S-8°31'W) and several older, probably near-ridge-generated seamounts. The newly discovered hotspot seamounts, and the previously-known seamounts of Bagration, Bonaparte and Kutuzov were mapped and sampled. Onboard geochemical studies confirm that they all show trace-element (Rb, Nb, Y, Zr, Sr) enriched, hotspot magma-type compositions. Morphological studies and the state of the samples collected from the seamounts (all have at least 1 mm-thick Mn crusts) suggest that none of the volcanoes is presently active, and that the St Helena hotspot is probably extinct at the present time. Josephine appears to be the youngest volcano, and one dredge here yielded fossil hydrothermal material (Fe-hydroxides). To test the hypothesis that the extinction of the hotspot is due to its magmas being channelled to the Mid-Atlantic Ridge, several dredges were taken on the ridge opposite St Helena. Furthermore, in the proposed influence zone of the St Helena plume head, Grattan seamount (9°44'S-12°48'W) was also sampled to examine whether its composition has been affected by the St Helena plume. During the transit from Las Palmas to St Helena, several sediment cores were taken in 3000 m water depth close to the ridge axis for palaeoclimatological work

Bericht und erste Ergebnisse der Meteor-Fahrt M 16/2 Recife-Belem, 28.4. - 21.5. 1991

With 97 Figs., 11 tabs.SIGLEAvailable from TIB Hannover: RO7630(19) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Bericht und erste Ergebnisse der Meteor-Fahrt M 16/1 Pointe Noire-Recife, 27.3. - 25.4.1991

With 59 figs., 13 tabs.SIGLEAvailable from TIB Hannover: RO7630(18) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Status of the Standard Electron Beam Diagnostics of the EU-XFEL

Outline• Setup and status accelerator• Diagnostics• BPMs• Toroids• Beam Loss Monitors• Wirescanner• Dosimetry• Summar

First Experience with the Standard Diagnostics at the European XFEL Injector

The injector of the European XFEL started beam operation in December 2015. Besides the gun and the accelerating section, containing a 1.3 and a 3.9 GHz accelerating module, it contains a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems of the whole XFEL are installed in the injector. Therefore the injector operation allows validating and proving of the diagnostics performances for the entire facility. Most of the standard diagnostics have been available from the very beginning of the beam operation and have been used for the monitoring of the first beam. In the following months the diagnostics have been optimized and used for improvements of beam quality. In this contribution, the first results and the operation experience of the standard beam diagnostics of the European XFEL are reported

Simultaneous operation of two soft x-ray free-electron lasers driven by one linear accelerator

Extreme-ultraviolet to x-ray free-electron lasers (FELs) in operation for scientific applications are up to now single-user facilities. While most FELs generate around 100 photon pulses per second, FLASH at DESY can deliver almost two orders of magnitude more pulses in this time span due to its superconducting accelerator technology. This makes the facility a prime candidate to realize the next step in FELs—dividing the electron pulse trains into several FEL lines and delivering photon pulses to several users at the same time. Hence, FLASH has been extended with a second undulator line and self-amplified spontaneous emission (SASE) is demonstrated in both FELs simultaneously. FLASH can now deliverMHzpulse trains to two user experiments in parallel with individually selected photon beam characteristics. First results of the capabilities of this extension are shown with emphasis on independent variation of wavelength, repetition rate, and photon pulse length