SPIDER: CMB polarimetry from the edge of space

Spider is a balloon-borne instrument designed to map the polarization of the millimeter-wave sky at large angular scales. Spider targets the B-mode signature of primordial gravitational waves in the cosmic microwave background (CMB), with a focus on mapping a large sky area with high fidelity at multiple frequencies. Spider ’s first long-duration balloon (LDB) flight in January 2015 deployed a total of 2400 antenna-coupled transition-edge sensors (TESs) at 90 GHz and 150 GHz. In this work we review the design and in-flight performance of the Spider instrument, with a particular focus on the measured performance of the detectors and instrument in a space-like loading and radiation environment. Spider ’s second flight in December 2018 will incorporate payload upgrades and new receivers to map the sky at 285 GHz, providing valuable information for cleaning polarized dust emission from CMB maps

Effect of varying the composition and nanostructure of organic carbonate-containing lyotropic liquid crystal polymer electrolytes on their ionic conductivity

Nanostructured composite electrolyte films consisting of a cross-linked lyotropic liquid crystal (LLC) monomer, an organic carbonate liquid electrolyte (propylene carbonate, dimethylcarbonate, diethylcarbonate) and a Li salt (LiClO_4, LiBF_4, LiPF_6) were systematically prepared and characterized at two electrolyte concentrations (0.245 and 1.0 m) and four liquid loading levels (5, 15, 30, 50 wt %). The LLC morphology of the films was investigated using polarized light microscopy and powder X-ray diffraction; their ionic conductivity was investigated using AC impedance measurements. Higher liquid electrolyte loadings and Li salt concentrations generally increased ionic conductivity, regardless of the liquid electrolyte or salt used. Some mixed-phase LLC morphologies displayed good ionic conductivity; however, as initially prepared, these formulations were at the limit of liquid uptake. In contrast, composites with a type II bicontinuous cubic (QII) LLC phase containing ordered, three-dimensional interconnected nanopores exhibited good conductivity using much less liquid electrolyte and a lower Li salt concentration, indicating that this structure is more amenable to ion transport than less ordered/uniform morphologies. When wetted with electrolyte solution and integrated into Li/fluorinated carbon coin cells, the QII films were sufficiently strong to act as an ion-conductive separator and displayed stable open-circuit potentials. Many of the mixed-phase films gave shorted cells