arXiv subjects

Steven E. Boggs

Publications and source records attributed to Steven E. Boggs.

111 records · Page 7Linked to original sources

arXiv2003

Statistical Uncertainty in the Re-Analysis of Polarization in GRB021206

We recently reported the first detection of an astrophysical gamma-ray polarization from GRB021206 using the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft. Our analysis suggested gamma-ray polarization at an astoundingly high level, 80+/-20%. A recent manuscript re-analyzes this event in the RHESSI data, and sets an upper limit on potential polarization of 4.1% -- clearly inconsistent with our initial analysis. This manuscript raises a number of important concerns about the analysis, which are already being addressed in a separate methods paper under preparation. We note here, however, that the limit set on the potential polarization by this re-analysis is significantly underestimated using their novel statistical methods.

astro-ph↗

arXiv2001

Properties of Pt Schottky Type Contacts On High-Resistivity CdZnTe Detectors

In this paper we present studies of the I-V characteristics of CdZnTe detectors with Pt contacts fabricated from high-resistivity single crystals grown by the high-pressure Brigman process. We have analyzed the experimental I-V curves using a model that approximates the CZT detector as a system consisting of a reversed Schottky contact in series with the bulk resistance. Least square fits to the experimental data yield 0.78-0.79 eV for the Pt-CZT Schottky barrier height, and <20 V for the voltage required to deplete a 2 mm thick CZT detector. We demonstrate that at high bias the thermionic current over the Schottky barrier, the height of which is reduced due to an interfacial layer between the contact and CZT material, controls the leakage current of the detectors. In many cases the dark current is not determined by the resistivity of the bulk material, but rather the properties of the contacts; namely by the interfacial layer between the contact and CZT material.

physics.ins-det↗

arXiv2000

Simulated Performance of a Germanium Compton Telescope

To build upon the goals of the upcoming INTEGRAL mission, the next generation soft gamma-ray (0.2-20 MeV) observatory will require improved sensitivity to nuclear line emission while maintaining high spectral resolution. We present the simulated performance of a germanium Compton telescope (GCT) design, which will allow a factor of ten improvement in sensitivity over INTEGRAL/SPI. We also discuss a number of issues concerning reconstruction techniques and event cuts, and demonstrate how these affect the overall performance of the telescope.

astro-ph↗