GRAPE - A Balloon-Borne Gamma-Ray Polarimeter Experiment

This paper reviews the development status of GRAPE (the Gamma-Ray Polarimeter Experiment), a hard X-ray Compton Polarimeter. The purpose of GRAPE is to measure the polarization of hard X-rays in the 50-300 keV energy range. We are particularly interested in X-rays that are emitted from solar flares and gamma-ray bursts (GRBs), although GRAPE could also be employed in the study of other astrophysical sources. Accurately measuring the polarization of the emitted radiation will lead to a better understating of both emission mechanisms and source geometries. The GRAPE design consists of an array of plastic scintillators surrounding a central high-Z crystal scintillator. The azimuthal distribution of photon scatters from the plastic array into the central calorimeter provides a measure of the polarization fraction and polarization angle of the incident radiation. The design of the detector provides sensitivity over a large field-of-view (>pi steradian). The design facilitates the fabrication of large area arrays with minimal deadspace. This paper presents the latest design concept and the most recent results from laboratory tests of a GRAPE science model.Comment: 6 pages; paper presented at the FRASCATI Workshop 2005 on Multifrequency Behaviour of High Energy Cosmic Sources; submitted to Chinese Journal of Astronomy and Astrophysic

In Appreciation of the Kind of Rhetoric We Learn in School: An Institutional Perspective on the Rhetorical Situation and on Education

Theoretical discussion of the rhetorical situation has been dedicated largely to questions of its ontology and of how it is constituted. Where this ontological orientation has inclined theorists to treat the concept as a theoretical premise, an institutional orientation would instead frame constructivist accounts of the rhetorical situation as a political-pedagogical commitment and treat the ethical obligations that arise from any given situation as bound to specific institutional forms. From an institutional perspective, the rhetorical situation is to conscience as the institution of school is to education. The distinction of both rhetorical situations and schools lies not in their contrivedness per se, but in the inventional capacities their contrived qualities sustain

Fear of etiolation in the age of professional passion

Recent analysis of academia credits neoliberalism for its destabilization. Neoliberalism alone does not explain academics’ conflicted attachments to a precarious professional life or the tendency to embrace normative conceptions of passion and shun professional decline. The quarantine on decline is analogous to the exemption that J.L. Austin imposed on theatre: both deny constitutive power to certain statements and harbor a fear of queerness. Four essays published in Text & Performance Quarterly illustrate how academics quarantine professional fears and doubts. A fifth finds that the deterioration of professional accomplishments loosens normative associations to make space for other, queer relations

Imbalances and Inequities: The Structure of Inquiry and Its Place in Rhetorical Studies

Inquiry’s place in rhetorical studies has long been contentious. Critics argue that academic professionalism and the rise of criticism and theory have diminished rhetoric as a pragmatic art. The recent trend in higher education toward greater restrictions on academic inquiry poses new problems for rhetorical studies, particularly where those restrictions exacerbate existing educational inequities. In the effort to address those inequities, a distinction needs to be made between old concerns with inquiry and the new issues any reorganization of inquiry will present. The generic support for inquiry that universities provide benefits rhetorical studies by lending structure to inquiry processes fraught with uncertainty and marked by impermanency. That support allows for the kind of careful engagement with possibility that rhetorical invention requires. The 2009 documentary film Naturally Obsessed: The Making of a Scientist illustrates the value to inquiry of professional conventions and other forms of generic support. Those same conventions serve rhetorical studies in similar ways

The Ethical and Professional Risks of Engaged Scholarship

The article reviews several books including Save the World on Your Own Time, by Stanley Fish, Challenging the Prison-Industrial Complex: Activism, Arts & Educational Alternatives, edited by Stephen John Hartnett, and The Ethics and Politics of Speech: Communication and Rhetoric in the Twentieth Century, by Pat J. Gehrke

Using LaX scintillator in a new low-background Compton telescope

The ability of Compton telescopes to perform imaging and spectroscopy in space depends directly on the speed and energy resolution of the calorimeter detectors in the telescope. The calorimeter detectors flown on space-borne or balloon-borne Compton telescopes have included NaI(Tl), CsI(Na), HPGe and liquid organic scintillator. By employing LaX scintillators for the calorimeter, one can take advantage of the unique speed and resolving power of the material to improve the instrument sensitivity and simultaneously enhance its spectroscopic performance and thus its imaging performance. We present a concept for a space-borne Compton telescope that employs LaX as a calorimeter and estimate the improvement in sensitivity over past realizations of Compton telescopes. With some preliminary laboratory measurements, we estimate that in key energy bands, typically corrupted with neutron-induced internal nuclear emissions, this design enjoys a twenty-fold improvement in background rejection