3D Particle Track Reconstrution in a Single Layer Cadmium-Telluride Hybrid Active Pixel Detector

In the past 20 years the search for neutrinoless double beta decay has driven many developements in all kind of detector technology. A new branch in this field are highly-pixelated semiconductor detectors - such as the CdTe-Timepix detectors. It compromises a cadmium-telluride sensor of 14 mm x 14 mm x 1 mm size with an ASIC which has 256 x 256 pixel of 55 \textmu m pixel pitch and can be used to obtain either spectroscopic or timing information in every pixel. In regular operation it can provide a 2D projection of particle trajectories; however, three dimensional trajectories are desirable for neutrinoless double beta decay and other applications. In this paper we present a method to obtain such trajectories. The method was developed and tested with simulations that assume some minor modifications to the Timepix ASIC. Also, we were able to test the method experimentally and in the best case achieved a position resolution of about 90 \textmu m with electrons of 4.4 GeV.Comment: 10 pages, 15 figure

HTS-Technology for hybrid electric aircraft

The world of transportation is in a transition: From combustion engines to electric machines. This change is getting more and more momentum on the land, on the sea and in recent years also in the air. On the one hand, electric aircraft is supposed to open absolutely new opportunities for urban mobility with such concepts as prosed and currently heaviliy investigated by Uber, Vahana, CityAirbus or Lilium. On the other hand electric aircraft and in particular hybrid electric aircraft will allow to reduce the COx, NOx and noise emissions as required by the ACARE 2050 goals. Although demonstrated by several proof-of-concepts maiden flights by Siemens in close collaboration with Diamond Aircraft, Magnus and EXTRA that hybrid electric flight is possible, there are many technical challenges on the road to the entry into service of hybrid electric regional jet. Siemens and Airbus have a started collaboration in June 2016 to adress jointly this challanges and make a large step towards this ambitious goal. The challenges relate mainly to the weight and efficiency of electric propulsion components. Motors and generators at the multi-MW scale have been available for industrial applications for a large time - however at such weights that render flying with them impossible. With a power-to-weight ratio of around 0.5 kW/kg traction drives for motors or ships are significantly heavier than gas turbines which have a typical power-to-weight ratio of about 5 kW/kg to 9 kW/kg. With the SP260D Siemens Aircraft developed a electric propulsion direct drive motor with power of 260 kW and a weight of roughly 50 kg, therefore a power-to-weight ratio of about 5.2 kW/kg which is the currently world record. For doing so we went to the edge of magnetic, mechanical, thermal and electric properties of materials and involved numerical optimization to be as lightweight as possible. Nonetheless we need to take an additional big step. How to go even further with lightweight electric machines? An immense opportunity could offer high tempereratur superconductors as they allow far higher airgap magnetic fields than the best NeFeB magnets and much higher current densities in the stator. In this talk I would like to adress in how far superconductivity could allow to significatly increase the power-to-weight ratio of hybrid electric propulsion systems and therefore be a key technology for hybrid electric aircraft

The Potential of Hybrid Pixel Detectors in the Search for the Neutrinoless Double-Beta Decay of Cd-116

We investigated the potential of the energy resolving hybrid pixel detector Timepix contacted to a CdTe sensor layer for the search for the neutrinoless double-beta decay of Cd-116. We found that a CdTe sensor layer with 3 mm thickness and 165 mu m pixel pitch is optimal with respect to the effective Majorana neutrino mass (m(beta beta)) sensitivity. In simulations, we were able to demonstrate a possible reduction of the background level caused by single electrons by approximately 75% at a specific background rate of 10(-3) counts/(kg x keV x yr) at a detection efficiency reduction of about 23% with track analysis employing random decision forests. Exploitation of the imaging properties with track analysis leads to an improvement in sensitivity to m(beta beta) by about 22%. After 5 years of measuring time, the sensitivity to m(beta beta) of a 420 kg CdTe experiment (90% Cd-116 enrichment) would be 59 meV on a 90% confidence level for a specific single-electron background rate of 10(-3) counts/(kg x keV x yr). The alpha-particle background can be suppressed by at least about six orders of magnitude. The benefit of the hybrid pixel detector technology might be increased significantly if drift-time difference measurements would allow reconstruction of tracks in three dimensions

Predesign Considerations for the DC Link Voltage Level of the CENTRELINE Fuselage Fan Drive Unit

Electric propulsion (EP) systems offer considerably more degrees of freedom (DOFs) within the design process of aircraft compared to conventional aircraft engines. This requires large, computationally expensive design space explorations (DSE) with coupled models of the single components to incorporate interdependencies during optimization. The purpose of this paper is to exemplarily study these interdependencies of system key performance parameters (KPIs), e.g., system mass and efficiency, for a varying DC link voltage level of the power transmission system considering the example of the propulsion system of the CENTRELINE project, including an electric motor, a DC/AC inverter, and the DC power transmission cables. Each component is described by a physically derived, analytical model linking specific subdomains, e.g., electromagnetics, structural mechanics and thermal analysis, which are used for a coupled system model. This approach strongly enhances model accuracy and simultaneously keeps the computational effort at a low level. The results of the DSE reveal that the system KPIs improve for higher DC link voltage despite slightly inferior performance of motor and inverter as the mass of the DC power transmission cable has a major share for a an aircraft of the size as in the CENTRELINE project. Modeling of further components and implementation of optimization strategies will be part of future work

Three dimensional photograph of single electron tracks through a scintillator

The reconstruction of particle trajectories makes it possible to distinguish between different types of charged particles. In high-energy physics, where trajectories are rather long, large size trackers must be used to achieve sufficient position resolution. However, in low-background experiments tracks are rather short and three dimensional trajectories could only be resolved in time-projection chambers so far. For detectors of large volume and therefore large drift distances, which are inevitable for low-background experiments, this technique is limited by diffusion of charge carriers. In this work we present a "proof-of-principle" experiment for a new method for the three dimensional tracking of charged particles by scintillation light: We used a setup consisting of a scintillator, mirrors, lenses and a novel imaging device (the hybrid photo detector) in order to image two projections of electron tracks through the scintillator. We took data at the T-24 beam-line at DESY with relativistic electrons with a kinetic energy of 5 GeV and from this data successfully reconstructed their three dimensional propagetion path in the scintillator. With our setup we achieved a position resolution of about 28 mum in the best case.Comment: 9 pages, 13 figures, 1 tabl

Detection of non-classical space-time correlations with a novel type of single-photon camera

During the last decades, multi-pixel detectors have been developed capable of registering single photons. The newly developed Hybrid Photon Detector camera has a remarkable property that it has not only spatial but also temporal resolution. In this work, we use this device for the detection of non-classical light from spontaneous parametric down-conversion and use two-photon correlations for the absolute calibration of its quantum efficiency

A holistic system approach for short range passenger aircraft with cryogenic propulsion system

Currently, hybrid-electric aircraft are under investigation as one possible solution to reduce the emissions of the aviation industry according to Flightpath 2050 of the European Union. To meet the drive trainʼs requirements on low mass while aiming for highest efficiency, superconducting technologies are regarded as a key enabling technology for drive train powers of several tens of megawatts. Within the German nationally funded project TELOS an exemplary mission profile and the physical measures of a 220-passenger aircraft are used to derive the requirements for a cryogenic-cooled serial hybrid-electric propulsion system. To optimize the total system performance, we subsequently evaluated the superconducting and cryogenic-cooled components by using computationally fast, analytical models. This approach allows quantifying the system performance by using component technologies being available today. In particular, the system performance of geared drive to direct drive propulsion units are compared and the influence of the DC bus voltage and the electric frequencies of the AC circuits on the mass and the efficiency of the drive trains are analysed