Deep Reconditioning Testing for near Earth Orbits

The problems and benefits of deep reconditioning to near Earth orbit missions with high cycle life and shallow discharge depth requirements is discussed. A simple battery level approach to deep reconditioning of nickel cadmium batteries in near Earth orbit is considered. A test plan was developed to perform deep reconditioning in direct comparison with an alternative trickle charge approach. The results demonstrate that the deep reconditioning procedure described for near Earth orbit application is inferior to the alternative of trickle charging

Status report of the CERN microwave axion experiment

"Light Shining Through the Wall" experiments can probe the existence of "axion like particles" through their weak coupling to photons. We have adapted such an experiment to the microwave regime and constructed the table top apparatus. This work presents an overview of the experimental setup and then focuses on our latest measurement run and its results. By operating the apparatus within a superconducting MRI magnet, competitive exclusion limits for axion like particles to the first generation optical light shining through the wall experiments have been achieved.Comment: Contributed to the 9th Patras Workshop on Axions, WIMPs and WISPs, Mainz, June 24-28, 201

Two years of on-orbit gallium arsenide performance from the LIPS solar cell panel experiment

The LIPS on-orbit performance of the gallium arsenide panel experiment was analyzed from flight operation telemetry data. Algorithms were developed to calculate the daily maximum power and associated solar array parameters by two independent methods. The first technique utilizes a least mean square polynomial fit to the power curve obtained with intensity and temperature corrected currents and voltages; whereas, the second incorporates an empirical expression for fill factor based on an open circuit voltage and the calculated series resistance. Maximum power, fill factor, open circuit voltage, short circuit current and series resistance of the solar cell array are examined as a function of flight time. Trends are analyzed with respect to possible mechanisms which may affect successive periods of output power during 2 years of flight operation. Degradation factors responsible for the on-orbit performance characteristics of gallium arsenide are discussed in relation to the calculated solar cell parameters. Performance trends and the potential degradation mechanisms are correlated with existing laboratory and flight data on both gallium arsenide and silicon solar cells for similar environments

Status report of the CERN light shining through the wall experiment with microwave axions and related aspects

One way to proof or exclude the existence of axion like particles is a microwave light shining through the wall experiment. In this publication we will emphasize on the engineering aspects of such a setup, currently under development at CERN. One critical point, to achieve meaningful results, is the electromagnetic shielding between axion-emitter and -receiver cavity, which needs to be in the order of 300 dB to improve over existing experimental bounds. The RF leakage or electromagnetic crosstalk between both cavities must be well controlled and quantified during the complete duration of the experiment. A very narrow band (in the 10^-6 Hz range) homodyne detection method is used to reveal the axion signal from background thermal noise. The current status of the experiment is presented.Comment: Contributed to the "7th Patras Workshop on Axions, WIMPs and WISPs", Mykonos June 26 - July 1 201

Status report and first results of the microwave LSW experiment at CERN

To detect or exclude the existence of hidden sector photons or axion like particles, a table-top "microwaves shining through the wall" experiment has been set up at CERN. An overview of the experimental layout is given, the technical challenges involved are reviewed and the measurement procedure including data-evaluation and its results to date are shown.Comment: Contributed to the 8th Patras Workshop on Axions, WIMPs and WISPs, Chicago, July 18-22, 201

Ecology of Mead\u27s Milkweed (\u3ci\u3eAsclepias meadii\u3c/i\u3e Torrey)

Mead\u27s milkweed (Asclepias meadii Torrey) is a plant of virgin prairies, whose pre-settlement range included much of the midwest. It is now a rare plant confined to prairie hay meadows, railroad rights-of-way, prairie preserves and pioneer cemeteries. Studies of approximately a hundred individual plants, producing hundreds of flowering and sterile stems, in the wild and in cultivation for seven years (1965-1971) indicated that it was a moderately-sized plant whose stems averaged 56 cm in height with sagittate sessile leaves with a herringbone arrangement of the veins. In late May to early June a mature stem produced a solitary, terminal, nodding umbel with an average of 12 flowers. Pollination was by digger bees (Anthophora spp.) and bumble bees (Bombus spp.). Approximately 6.4% of the flowering stems produced a long narrow pod averaging 12 cm in length and 1.3 cm in diameter with approximately 60 seeds per pod. Seed germination was relatively low (47.6%). Some plants in virgin prairies and in cultivation were over a quarter century old, and indications are they may live for a century or longer. In contrast to most milkweeds, the seedlings were difficult to grow. Four or more years were usually required to reach maturity. Like most milkweeds, a number of insects were associated with the plant. Most damaging were the larvae of the milkweed beetles (Tetraopes spp.) and milkweed weevils (Rhyssematus spp.) that fed on the roots and the adult weevils that girdled the peduncle causing the eventual collapse of the terminal umbel

First results of the CERN Resonant WISP Search (CROWS)

The CERN Resonant WISP Search (CROWS) probes the existence of Weakly Interacting Sub-eV Particles (WISPs) like axions or hidden sector photons. It is based on the principle of an optical light shining through the wall experiment, adapted to microwaves. Critical aspects of the experiment are electromagnetic shielding, design and operation of low loss cavity resonators and the detection of weak sinusoidal microwave signals. Lower bounds were set on the coupling constant $g = 4.5 \cdot 10^{-8}$GeV$^{-1}$ for axion like particles with a mass of $m_a = 7.2 \mu$eV. For hidden sector photons, lower bounds were set for the coupling constant $\chi = 4.1 \cdot 10^{-9}$ at a mass of $m_{\gamma'} = 10.8 \mu$eV. For the latter we were probing a previously unexplored region in the parameter space

A microwave paraphoton and axion detection experiment with 300 dB electromagnetic shielding at 3 GHz

For the microwave equivalent of "light shining through the wall" (LSW) experiments, a sensitive microwave detector and very high electromagnetic shielding is required. The screening attenuation between the axion generating cavity and the nearby detection cavity should be greater than 300 dB, in order to improve over presently existing exclusion limits. To achieve these goals in practice, a "box in a box" concept was utilized for shielding the detection cavity, while a vector signal analyzer was used as a microwave receiver with a very narrow resolution bandwidth in the order of a few micro-Hz. This contribution will present the experimental layout and the results to date.Comment: Presented at 3rd International Particle Accelerator Conference 2012, New Orleans, LA, USA, 20 - 25 May 201