arXiv subjects

Scott Porter

Publications and source records attributed to Scott Porter.

3 recordsLinked to original sources

arXiv2025

Ground calibration plan for the Athena/X-IFU microcalorimeter spectrometer

The X-ray Integral Field Unit is the X-ray imaging spectrometer on-board one of ESA's next large missions, Athena. Athena is set to investigate the theme of the Hot and Energetic Universe, with a launch planned in the late-2030s. Based on a high sensitivity Transition Edge Sensor (TES) detector array operated at very low temperature (50 mK), X-IFU will provide spatially resolved high resolution spectroscopy of the X-ray sky in the 0.2-12 keV energy band, with an energy resolution goal of 4 eV up to 7 keV [3 eV design goal]. This paper presents the current calibration plan of the X-IFU. It provides the requirements applicable to the X-IFU calibration, describes the overall calibration strategy, and details the procedure and sources needed for the ground calibration of each parameter or characteristics of the X-IFU.

astro-ph.IM↗

arXiv2018

An X-ray spectroscopic search for dark matter and unidentified line signatures in the Perseus cluster with Hitomi

We present results of a search for unidentified line emission and absorption signals in the 2-12keV energy band of spectra extracted from Perseus Cluster core region observations obtained with the 5eV energy resolution Hitomi Soft X-ray Spectrometer. No significant unidentified line emission or absorption is found. Line flux upper limits (1 sigma per resolution element) vary with photon energy and assumed intrinsic width, decreasing from 100 photons cm$^{-2}$ s$^{-1}$ sr $^{-1}$ at 2keV to $<10$ cm$^{-2}$ s$^{-1}$ sr $^{-1}$ over most of the 5-10 keV energy range for a Gaussian line with Doppler broadening of 640 km/s. Limits for narrower and broader lines have a similar energy dependence and are systematically smaller and larger, respectively. These line flux limits are used to constrain the decay rate of hypothetical dark matter candidates. For the sterile neutrino decay rate, new constraints over the the mass range of 4-24 keV with mass resolution better than any previous X-ray analysis are obtained. Additionally, the accuracy of relevant thermal spectral models and atomic data are evaluated. The Perseus cluster spectra may be described by a composite of multi-temperature thermal and AGN power-law continua. Superposed on these, a few line emission signals possibly originating from unmodeled atomic processes (including Si XIV and Fe XXV) are marginally detected and tabulated. Comparisons with previous X-ray upper limits and future prospects for dark matter searches using high-energy resolution spectroscopy are discussed.

astro-ph.HE↗

arXiv2016

Multimode bolometer development for the PIXIE instrument

The Primordial Inflation Explorer (PIXIE) is an Explorer-class mission concept designed to measure the polarization and absolute intensity of the cosmic microwave background. In the following, we report on the design, fabrication, and performance of the multimode polarization-sensitive bolometers for PIXIE, which are based on silicon thermistors. In particular we focus on several recent advances in the detector design, including the implementation of a scheme to greatly raise the frequencies of the internal vibrational modes of the large-area, low-mass optical absorber structure consisting of a grid of micromachined, ion-implanted silicon wires. With $\sim30$ times the absorbing area of the spider-web bolometers used by Planck, the tensioning scheme enables the PIXIE bolometers to be robust in the vibrational and acoustic environment at launch of the space mission. More generally, it could be used to reduce microphonic sensitivity in other types of low temperature detectors. We also report on the performance of the PIXIE bolometers in a dark cryogenic environment.

astro-ph.IM↗