Ion-lithium collision dynamics studied with an in-ring MOTReMi

We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the 'MOTReMi', is a combination of a magneto-optical trap (MOT) and a Reaction Microscope (ReMi). Operated in an ion-storage ring, the new setup enables to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In first experiments on collisions with 1.5 MeV/amu O$^{8+}$-Li the pure ionization of the valence electron as well as ionization-excitation of the lithium target has been investigated

Target electron ionization in Li2+-Li collisions: A multi-electron perspective

Target electron removal in Li2+-Li collisions at 2290 keV/amu is studied experimentally and theoretically for ground and excited lithium target configurations. It is shown that in outer-shell ionization a single-electron process plays the dominant part. However, the K-shell ionization results are more difficult to interpret. According to our calculations, the process is shown to be strongly single-particle like. On one hand, a high resemblance between theoretical single-particle ionization and exclusive inner-shell ionization is demonstrated, and contributions from multi-electron processes are found to be weak. On the other hand, it is indicated by the discrepancy between experimental and single-particle theoretical results that multi-electron processes involving ionization from the outer-shell may play a crucial role

Der elegante Theetisch oder die Kunst, einen glänzenden Zirkel auf eine geschmackvolle und anständige Art ohne großen Aufwand zu bewirthen

DER ELEGANTE THEETISCH ODER DIE KUNST, EINEN GLÄNZENDEN ZIRKEL AUF EINE GESCHMACKVOLLE UND ANSTÄNDIGE ART OHNE GROSSEN AUFWAND ZU BEWIRTHEN Der elegante Theetisch oder die Kunst, einen glänzenden Zirkel auf eine geschmackvolle und anständige Art ohne großen Aufwand zu bewirthen ( - ) Einband ( - ) Frontispiz ( - ) Titelseite (1) Nachricht (2) Einleitung. (3) Von der Bereitung des Thee's. (9) Etwas vom Thee-Geräthe. (11) Thee. (13) Verschiedene Sorten Punsch. (14) Frühstücks-Getränke. (18) Kühlende Getränke. (21) Gelées, blanc mangés und glacirte Früchte. (25) Glacirte Früchte. (31) Feine Backwerke. (33) Torten. (47) Glasur (51) Waffeln und Hohllippen. (59) Backwerke aus Schmalz. (61) Blätter-Teig. (64) Torte von Blätterteig (67) Hefen-Backwerk. (71) Von dem Gefrornen und dessen Zubereitung (75) Inhalt. (89) Verlags-Bücher von Wilhelm Hoffmann in Weimar ( - ) Blatt mit handschriftlichen Notizen, u.a. zu einem "Pot Pouri." ( -

Comparison of experimental and theoretical fully differential cross sections for single ionization of the 2s and 2p states of Li by Li2+ ions

This paper presents experimental measurements of the fully differential cross section for 16. MeV Li2+ single ionization of 2s ground and the 2p excited state of Li in the azimuthal plane. Data were obtained for three different ejected electron energies and two different projectile momentum transfers. The experimental results are compared with theoretical three-body continuum distorted wave-Eikonal initial state calculations and reasonable good agreement is found between theory and experiment. Theory predicts a double peak structure for one of the measured cases and the physical effects producing the double peak are investigated by performing calculations with different interactions either turned on or off

Reliability and failure analysis of solder joints in flip chip LEDs via thermal impedance characterisation

Flip chip technology has made significant improvements to LED chip on board (COB) packages and modules by reducing thermal resistance compared with traditional wire bonded LEDs. However, one of the critical issues of flip chip packaged LEDs is the reliability of their solder interconnects, which are responsible for the heat transfer to the substrate. Based on a supply switching test, also called power cycle test, a model for monitoring and reliability was done to describe the remaining lifetime and additional the solder fatigue. Therefore, changes in thermal resistance of the LED-module were measured and correlated with solder fatigue of the LED flip chip package. Thermal impedance measurements were performed to monitor the status of the LED-module. Detailed analyses, comparing with the initial state, allow the evaluation of the occurring temperature swing of each LED chip. Single chip analysis combined with a thermal resistance driven monitoring model allows the calculation of remaining lifetime at each time during testing and beyond the first chip failure in a multi chip LED-module. Accordingly, it could be shown that the thermal impedance is a powerful tool for reliability monitoring and failure analysis

Study on the temperature-dependent thermal resistance matrix of a multi-chip LED-matrix

The solid lighting industry comply with costumer's requirements of high light output and a higher grade of functionality, especially in the automotive sector. The integration of multiple LED-chips on one illuminant has the advantage of weight and size reduction. However, multiple LED-chips lead to increased power density; to get rid of their produced heat, an energy strategy is necessary. The key term is Thermal Management, to understand the thermal behavior of a LED lighting system. In this paper, the investigation of the thermal interdependencies of a 4-chip-matrix was presented. The thermal characterization was done by thermal transient measurements of each chip and their structure functions, followed by the study of its thermal resistance (Rth) matrix. The Rth-matrix represented the thermal properties of each LED-chip and its interdependency. As supplement of the thermal characterization, thermal simulations were carried out. Moreover, the Rth-matrix was used to analyze the LED-matrix in terms of their temperature dependency. The heat path investigation via Rth-matrix showed different behaviors of the 4-chip-matrix by using different heat sink temperatures. The method was used as an evaluation tool for thermal management of LED-matrix systems

Polarization and Interference Effects in Ionization of Li by Ion Impact

We present initial-state selective fully differential cross sections for ionization of lithium by 24 MeV O8+ impact. The data for ionization from the 2s and 2p states look qualitatively different from each other and from 1s ionization of He. For ionization from the 2p state, to which in our study the mL=-1 substate predominantly contributes, we observe orientational dichroism and for 2s ionization pronounced interference which we trace back to the nodal structure of the initial-state wave function