53 research outputs found

    Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

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    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity

    Calibration of the MaGIXS experiment II: Flight Instrument Calibration

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    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a sounding rocket experiment that observes the soft X-ray spectrum of the Sun from 6.0 - 24 Angstrom (0.5 - 2.0 keV), successfully launched on 30 July 2021. End-to-end alignment of the flight instrument and calibration experiments are carried out using the X-ray and Cryogenic Facility (XRCF) at NASA Marshall Space Flight Center. In this paper, we present the calibration experiments of MaGIXS, which include wavelength calibration, measurement of line spread function, and determination of effective area. Finally, we use the measured instrument response function to predict the expected count rates for MaGIXS flight observation looking at a typical solar active regionComment: 20 pages, 16 figures, Accepted for publication in the Astrophysical Journa

    The First Flight of the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS)

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    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment launched on July 30, 2021 from the White Sands Missile Range in New Mexico. MaGIXS is a unique solar observing telescope developed to capture X-ray spectral images, in the 6 - 24 Angstrom wavelength range, of coronal active regions. Its novel design takes advantage of recent technological advances related to fabricating and optimizing X-ray optical systems as well as breakthroughs in inversion methodologies necessary to create spectrally pure maps from overlapping spectral images. MaGIXS is the first instrument of its kind to provide spatially resolved soft X-ray spectra across a wide field of view. The plasma diagnostics available in this spectral regime make this instrument a powerful tool for probing solar coronal heating. This paper presents details from the first MaGIXS flight, the captured observations, the data processing and inversion techniques, and the first science results.Comment: 20 pages, 18 figure

    The High-Resolution Coronal Imager, Flight 2.1

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    The third flight of the High-Resolution Coronal Imager (Hi-C 2.1) occurred on May 29, 2018; the Sounding Rocket was launched from White Sands Missile Range in New Mexico. The instrument has been modified from its original configuration (Hi-C 1) to observe the solar corona in a passband that peaks near 172 Å, and uses a new, custom-built low-noise camera. The instrument targeted Active Region 12712, and captured 78 images at a cadence of 4.4 s (18:56:22 – 19:01:57 UT; 5 min and 35 s observing time). The image spatial resolution varies due to quasi-periodic motion blur from the rocket; sharp images contain resolved features of at least 0.47 arcsec. There are coordinated observations from multiple ground- and space-based telescopes providing an unprecedented opportunity to observe the mass and energy coupling between the chromosphere and the corona. Details of the instrument and the data set are presented in this paper

    Natural law, non-voluntary euthanasia, and public policy

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    © 2019 by Emerald Publishing Limited. Natural Law philosophy asserts that there are universally binding and universally evident principles that can be determined to guide the actions of persons. Moreover, many of these principles have been enshrined in both statute and common law, thus ensuring their saliency for staff and institutions charged with palliative care. The authors examine the often emotive and politicized matter of (non-voluntary) euthanasia – acts or omissions made with the intent of causing or hastening death – with reference to Natural Law philosophy. This leads us to propose a number of important public policy remedies to ensure dignity in dying for the patient, and their associates

    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS)

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    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a sounding rocket instrument that flew on July 30, 2021 from the White Sands Missile Range, NM. The instrument was designed to address specific science questions that require differential emission measures of the solar soft X-ray spectrum from 6 – 25[Formula: see text]Å(0.5 – 2.1[Formula: see text]keV). MaGIXS comprises a Wolter-I telescope, a slit-jaw imaging system, an identical pair of grazing incidence paraboloid mirrors, a planar grating and a CCD camera. While implementing this design, some limitations were encountered in the production of the X-ray mirrors, which ended up as a catalyst for the development of a deterministic polishing approach and an improved meteorological technique that utilizes a computer-generated hologram (CGH). The opto-mechanical design approach addressed the need to have adjustable and highly repeatable interfaces to allow for the complex alignment between the optical sub-assemblies. The alignment techniques employed when mounting the mirrors and throughout instrument integration and end-to-end testing are discussed. Also presented are spatial resolution measurements of the end-to-end point-spread-function that were obtained during testing in the X-ray Cryogenic Facility (XRCF) at NASA Marshall Space Flight Center. Lastly, unresolved issues and off-nominal performance are discussed

    The First Flight of the Marshall Grazing Incidence X-Ray Spectrometer (MaGIXS)

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    The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) sounding rocket experiment launched on 2021 July 30 from the White Sands Missile Range in New Mexico. MaGIXS is a unique solar observing telescope developed to capture X-ray spectral images of coronal active regions in the 6–24 Å wavelength range. Its novel design takes advantage of recent technological advances related to fabricating and optimizing X-ray optical systems, as well as breakthroughs in inversion methodologies necessary to create spectrally pure maps from overlapping spectral images. MaGIXS is the first instrument of its kind to provide spatially resolved soft X-ray spectra across a wide field of view. The plasma diagnostics available in this spectral regime make this instrument a powerful tool for probing solar coronal heating. This paper presents details from the first MaGIXS flight, the captured observations, the data processing and inversion techniques, and the first science results

    The Consequences of Liberal Modernity: Explaining and Resisting Neoliberalism Through Alasdair MacIntyre

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    Neoliberalism is, in various ways, radically new. it is nevertheless constructed from the conditions of liberal modernity, the inadequacies of which are crucial to neoliberal success. Liberalism in practice restricts moral agency through an impoverished, structurally-reinforced conception of practical reasoning, as Alasdair MacIntyre argues, and this is important to understanding neoliberal durability. This paper argues that a bureaucratic culture that fails to evaluate or critically question the ends it pursues is both symptomatic of liberal inadequacies and a key factor in neoliberal success. Beyond its purely explanatory power, there is a political relevance to MacIntyre’s Aristotelian-inspired politics of local community. It is from those practices and communal movements that embody alternative conceptions of the good, that those interested in resisting neoliberalism can learn how it becomes possible to successfully challenge aspects of the contemporary social order

    Leadership after virtue: MacIntyre’s critique of management reconsidered

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    MacIntyre argues that management embodies emotivism, and thus is inherently amoral and manipulative. His claim that management is necessarily Weberian is, at best, outdated, and the notion that management aims to be neutral and value free is incorrect. However, new forms of management, and in particular the increased emphasis on leadership which emerged after MacIntyre’s critique was published, tend to support his central charge. Indeed, charismatic and transformational forms of leadership seem to embody emotivism to a greater degree than do more Weberian, bureaucratic forms of management, so MacIntyre’s central contention about our emotivistic culture seems to be well-founded. Having criticised the details but defended the essence of MacIntyre’s critique of management, this paper sketches a MacIntyrean approach to management and leadership by highlighting the affinities between MacIntyre’s political philosophy and Greenleaf’s concept of servant leadership

    “We ought to eat in order to work, not vice versa”: MacIntyre, practices, and the best work for humankind.

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    This paper draws a distinction between ‘right MacIntyreans’ who are relatively optimistic that MacIntyre’s vision of ethics can be realised in capitalist society, and ‘left MacIntyreans’ who are sceptical about this possibility, and aims to show that the ‘left MacIntyrean’ position is a promising perspective available to business ethicists. It does so by arguing for a distinction between ‘community-focused’ practices and ‘excellence-focused’ practices. The latter concept fulfils the promise of practices to provide us with an understanding of the best work for humankind and highlights the affinities between MacIntyre’s concept of a practice and Marx’s conception of good work as free, creative activity. The paper concludes with a suggestion that we reflect on the best forms of work so that we can strive to ensure the very best activities, those most consonant with our flourishing, one day become available to all
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