Antenna-coupled TES bolometers used in BICEP2, Keck array, and SPIDER

We have developed antenna-coupled transition-edge sensor (TES) bolometers for a wide range of cosmic microwave background (CMB) polarimetry experiments, including BICEP2, Keck Array, and the balloon borne SPIDER. These detectors have reached maturity and this paper reports on their design principles, overall performance, and key challenges associated with design and production. Our detector arrays repeatedly produce spectral bands with 20%-30% bandwidth at 95, 150, or 220~GHz. The integrated antenna arrays synthesize symmetric co-aligned beams with controlled side-lobe levels. Cross-polarized response on boresight is typically ~0.5%, consistent with cross-talk in our multiplexed readout system. End-to-end optical efficiencies in our cameras are routinely 35% or higher, with per detector sensitivities of NET~300 uKrts. Thanks to the scalability of this design, we have deployed 2560 detectors as 1280 matched pairs in Keck Array with a combined instantaneous sensitivity of ~9 uKrts, as measured directly from CMB maps in the 2013 season. Similar arrays have recently flown in the SPIDER instrument, and development of this technology is ongoing.Comment: 16 pgs, 20 fig

Epicureans on Death and Lucretius’ Squandering Argument

Lucretius follows his symmetry argument that one should not fear death with a dialectical strategy, the squandering argument. The dialectical presumption behind the squandering argument is that its audience is not an Epicurean, so squanders their life. The question is whether the squandering argument (and the other Epicurean arguments that one should not fear death) works on lives that by Epicurean standards are not squandered.</jats:p

The Stoic Sage Does not Err: An Error?

The Stoics held that the wise person does not err. This thesis was widely criticized in the ancient world and runs afoul of contemporary fallibilist views in epistemology. Was this view itself an error? On one line, the view can be modified to accommodate many of the critical lines against it. Some of these lines of modification are consistent with traditional Stoic value theory (for example, importing the notion of preferred indifferents into epistemic considerations). However, others require larger modifications to Stoic axiology (in particular, a revision of the equality of errors thesis). A version of the no errors thesis emerges as defensible against the criticisms of the view, but there is then the question as to whether it is an orthodox Stoicism.</jats:p