Bernhard Seifert

Measurement of Gravitomagnetic and Acceleration Fields around Rotating Superconductors

It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so‐called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper‐pairs. A similar field is predicted from Einstein’s general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so‐called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagne...

Anomalous fiber optic gyroscope signals observed above spinning rings at low temperature

Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earths rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earths spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals.

Investigation of Frame‐Dragging‐Like Signals from Spinning Superconductors using Laser Gyroscopes

The search for frame dragging around massive rotating objects such as the Earth is an important test for general relativity and is actively pursued with the LAGEOS and Gravity Probe‐B satellites. Within the classical framework, frame dragging is independent of the state (normal or coherent) of the test mass. This was recently challenged by proposing that a large frame‐dragging field could be responsible for a reported anomaly of the Cooper‐pair mass found in Niobium superconductors. In 2003, a test program was initiated at the Austrian Research Centers to investigate this conjecture using sensitive accelerometers and fiber optic gyroscopes in the close vicinity of fast spinning rings at cryogenic temperatures. This paper will discuss the measurements recently obtained with the fiber optic gyroscopes. They show, that the angular velocity applied to the superconductor can indeed be seen on the sensors below a critical temperature. The signal amplitude is about 8 orders of magnitude below the values applied ...

Measuring the dependence of weight on temperature in the low-temperature regime using a magnetic suspension balance

A novel set-up was developed that allows us to cool samples close to liquid helium temperatures, measure their exact temperature and determine their weight in a buoyancy-free environment along a wide temperature range using a magnetic suspension balance. This allows for the first time to accurately determine the weight of both high-Tc (BSCCO and YBCO) and low-Tc (Nb) superconductors during their phase transition. Our data allow us to put limits on possible weight changes over temperature (α < 2 × 10−8 K−1 for copper) as well as violations of the weak equivalence principle for superconductors while passing their critical temperature (η < 2 × 10−3).

Precision angular velocity response of a fiber-optic gyroscope using a piezo-nano-rotation table

Modern fiber-optic gyroscopes are calibrated using the Earths rotation or stepper motor actuated rotation tables. We investigated the angular velocity resolution of the Optolink SRS-1000 fiber-optic gyroscope using a piezo-activated rotation table down to angular velocity steps of 1 × 10−7 rad s−1 with an accuracy of 1.5 × 10−8 rad s−1. To our knowledge, these are the smallest velocity steps resolved and reported in the literature so far. Our results show that such a gyroscope may be also used for nanopositioning purposes in addition to its usual navigation application.

Experimental Study of the Machian Mass Fluctuation Effect Using a μN Thrust Balance

Already since 1990, James F. Woodward, professor of physics at the California State University, provided a set of equations showing that it should be possible, via Mach’s Principle, to change transiently the mass of a body. Several devices were developed, that suggest that the phenomenon is real. The main goal of the experimental campaign proposed here is to perform an independent test for the existence of machian mass fluctuations: we will study the behavior of a test device using a very sensitive thrust balance developed for field emission thrusters. The balance has a sub μN accuracy, which should prove the effect at least with a thrust‐to‐noise ratio of 100:1. This mass fluctuation effect, if proved to be genuine, would open the doors to a new kind of propellantless propulsion which could be directly applied to space exploration. Another aspect of our work is to explore also the possibility to achieve higher power efficiency and a more compact design, making then these devices attractive for practical ...

Performance Mapping and Qualification of the IFM Nano Thruster FM for in Orbit Demonstration

The Aerospace Department at FOTEC has been developing the mN-FEEP technology under ESA research contracts for the last decades with the purpose to create a highly controllable and efficient propulsion technology for future science missions. The mNFEEP thrusters use a crown of sharpened porous Tungsten needles which are wetted with liquid Indium. This crown is raised to a high positive potential to emit and accelerate In ions. This thruster technology has undergone extensive testing in recent years, including performance mapping of more than hundred emitters and lifetime testing up to more than 13.000 h. Based on this technology, the IFM Nano thruster has been developed as a commercial product for small satellites. This integrated ion propulsion system fits into a volume of less than a single unit CubeSat. In 2017, the first flight model has been manufactured to be flown on an in-orbit demonstration mission, supported by the ESA IOD program ATLAS. This paper presents the results from the extensive test campaigns on proto-flight model level, including efficiency mapping of all subsystems and the validation of the neutralization strategy. The results show that the IFM Nano thruster design is fully functional and provide an outlook on the performance to be expected during in-orbit operation.