Although it is often believed that the coldness of space is ideally suited for performing measurements at cryogenic temperatures, this must be regarded with caution for two reasons: firstly, the ...sensitive instrument must be completely shielded from the strong solar radiation and therefore, e.g., either be placed inside a satellite or externally on the satellite's shaded side. Secondly, any platform hosting such an experiment in space generally provides an environment close to room temperature for the accommodated equipment. To obtain cryogenic temperatures without active cooling, one must isolate the instrument from radiative and conductive heat exchange with the platform as well as possible. We perform analyses on the limits of this passive cooling method for a recently proposed experiment to observe the decoherence of quantum superpositions of massive objects. In this context, we obtain temperatures of 27 K for the optical bench and 16 K for the critical experimental volume. Our analyses and conclusions can readily be applied to similar science experiments requiring a cryogenic environment in space.
The book series of the Institut für Europäische Kulturgeschichte (Institute of European Cultural History) in Augsburg collects contributions to the cultural history of European premodernity, its ...ancient and medieval prerequisites, and its consequences and continuities reaching into modernity. In addition to topics such as information, knowledge, media and communication, and historical network research, it covers questions of European cultures of remembrance and collective identities.
Die Welser Mark Häberlein, Johannes Burkhardt / Mark Häberlein, Johannes Burkhardt
2014
eBook
The book series of the Institut für Europäische Kulturgeschichte (Institute of European Cultural History) in Augsburg collects contributions to the cultural history of European premodernity, its ...ancient and medieval prerequisites, and its consequences and continuities reaching into modernity. In addition to topics such as information, knowledge, media and communication, and historical network research, it covers questions of European cultures of remembrance and collective identities.
Das Friedensfest Johannes Burkhardt, Stephanie Haberer / Johannes Burkhardt, Stephanie Haberer
2011
eBook
The book series of the Institut für Europäische Kulturgeschichte (Institute of European Cultural History) in Augsburg collects contributions to the cultural history of European premodernity, its ...ancient and medieval prerequisites, and its consequences and continuities reaching into modernity. In addition to topics such as information, knowledge, media and communication, and historical network research, it covers questions of European cultures of remembrance and collective identities.
Display omitted
•We improved performance and design aspects of a radiatively cooled instrument.•A heat-flow analysis showed near optimal performance of the shield design.•A simple modification to ...imaging optics allowed further improvements.•We studied the thermal behavior for different orbital cases.•A transfer-function analysis showed strong attenuation of thermal variations.
Passive cooling of scientific instruments via thermal radiation to deep space offers many advantages over active cooling in terms of mission cost, lifetime and the achievable quality of vacuum and microgravity. Motivated by the mission proposal MAQRO to test the foundations of quantum physics harnessing a deep-space environment, we investigate the performance of a radiatively cooled instrument, where the environment of a test particle in a quantum superposition has to be cooled to less than 20K. We perform a heat-transfer analysis between the instrument components and a transfer-function analysis on thermal oscillations induced by the spacecraft interior and dissipative sources. The thermal behavior of the instrument is discussed for an orbit around a Lagrangian point and for a highly elliptical Earth orbit. Finally, we investigate possible design improvements. These include a mirror-based design of the imaging system on the optical bench (OB) and an extension of the heat shields.
Wenn empirische Studien zur (Betreuungs-)Situation des wissenschaftlichen Nachwuchses vor allem statistisch vorgehen, verwischen sich viele Einzelschicksale in den Mittelwerten. Johannes Burkhardt ...schildert in unserer (je nach Ereignis) Sarkasmus- bzw. Satire-Spalte des HSW "Love Letters to Higher Education", wie es bei ihm und in vielen anderen Fällen zugeht. Der Herausgeber kann die geschilderte Lage dutzendfach bestätigen. Und sie ist folgenreich für ganze Lebensläufe. Hier geht es nicht um Unselbständigkeit und individuelles Versagen (die gibt es natürlich auch), sondern um mangelnde Fürsorge und Ausnutzung von Abhängigen. Die Antwort kann nicht nur Promotionskolleg (o.ä.) sein. Dazu gibt es auch weiterhin viel zu viele individuelle Promotionsvorhaben, an denen anzusetzen notwendig ist. Wir laden aus Anlass dieses Textes ausdrücklich dazu ein, kurze Schilderungen von Konstellationen, die das krasse Gegenteil ursprünglich gedachter Ziele oder andere Missstände von breiterer Bedeutung spiegeln, dem Herausgeber persönlich einzureichen. Wenn die Autor/innen sich nicht zu einem umfangreicheren Artikel veranlasst sehen, kann der Text (1-1,5 Seiten) in der Sparte "Love Letters to Higher Education" publiziert werden. Die Erfahrung zeigt, dass einige abhängig Beschäftigte die Situation nicht zu berichten wagen. In solchen Fällen setzen wir den Schutzmechanismus des Pseudonyms ein. Nur der Herausgeber kennt die Identität der Autor/innen. Entsprechende Post ist zu richten an: webler@universitaetsverlagwebler.de. (HDZD/Text übernommen).
Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth’s gravitational field, in navigation & ranging, and in fundamental physics such as ...tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species
85
Rb/
87
Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry, the detection unit, the vacuum system for 10
−11
mbar ultra-high vacuum generation, and the high-suppression factor magnetic shielding as well as the thermal control system. The laser system is based on a hybrid approach using fiber-based telecom components and high-power laser diode technology and includes all laser sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and switching of the laser beams is carried out on an optical bench using Zerodur bonding technology. The instrument consists of 9 units with an overall mass of 221 kg, an average power consumption of 608 W (814 W peak), and a volume of 470 liters which would well fit on a satellite to be launched with a Soyuz rocket, as system studies have shown.
Die Buchreihe des Instituts für Europäische Kulturgeschichte in Augsburg versammelt Beiträge zur Kulturgeschichte der europäischen Vormoderne, ihrer antiken und mittelalterlichen Voraussetzungen ...sowie ihrer in die Moderne hineinreichenden Aus- und Nachwirkungen. Neben Themen wie Information, Wissen, Medien- und Kommunikation sowie historische Netzwerkforschung geht es um Fragen der europäischen Erinnerungskulturen und kollektive Identitäten.
Die Buchreihe des Instituts für Europäische Kulturgeschichte in Augsburg versammelt Beiträge zur Kulturgeschichte der europäischen Vormoderne, ihrer antiken und mittelalterlichen Voraussetzungen ...sowie ihrer in die Moderne hineinreichenden Aus- und Nachwirkungen. Neben Themen wie Information, Wissen, Medien- und Kommunikation sowie historische Netzwerkforschung geht es um Fragen der europäischen Erinnerungskulturen und kollektive Identitäten.
Die Welser Häberlein, Mark; Burkhardt, Johannes
2014, 2002, 2002-01-01, Letnik:
16
eBook
Die Buchreihe des Instituts für Europäische Kulturgeschichte in Augsburg versammelt Beiträge zur Kulturgeschichte der europäischen Vormoderne, ihrer antiken und mittelalterlichen Voraussetzungen ...sowie ihrer in die Moderne hineinreichenden Aus- und Nachwirkungen. Neben Themen wie Information, Wissen, Medien- und Kommunikation sowie historische Netzwerkforschung geht es um Fragen der europäischen Erinnerungskulturen und kollektive Identitäten.
PDF
