arXiv subjects

Peter Hastings

Publications and source records attributed to Peter Hastings.

5 recordsLinked to original sources

arXiv2018

Miniaturized atmospheric ionization detector

A small scintillator-based detector for atmospheric ionization measurements has been developed, partly in response to a need for better ionization data in the weather-forming regions of the atmosphere and partly with the intention of producing a commercially available device. The device can measure both the count rate and energy of atmospheric ionizing radiation. Here we report results of a test flight over the UK in December 2017 where the detector was flown with two Geiger counters on a meteorological radiosonde. The count rate profile with height was consistent both with the Geigers and with previous work. The energy of incoming ionizing radiation increased substantially with altitude.

physics.ins-det↗

arXiv2015

The Mid-Infrared Instrument for the James Webb Space Telescope, VI: The Medium Resolution Spectrometer

We describe the design and performance of the Medium Resolution Spectrometer (MRS) for the JWST-MIRI instrument. The MRS incorporates four coaxial spectral channels in a compact opto-mechanical layout that generates spectral images over fields of view up to 7.7 X 7.7 arcseconds in extent and at spectral resolving powers ranging from 1,300 to 3,700. Each channel includes an all-reflective integral field unit (IFU): an 'image slicer' that reformats the input field for presentation to a grating spectrometer. Two 1024 X 1024 focal plane arrays record the output spectral images with an instantaneous spectral coverage of approximately one third of the full wavelength range of each channel. The full 5 to 28.5 micron spectrum is then obtained by making three exposures using gratings and pass-band-determining filters that are selected using just two three-position mechanisms. The expected on-orbit optical performance is presented, based on testing of the MIRI Flight Model and including spectral and spatial coverage and resolution. The point spread function of the reconstructed images is shown to be diffraction limited and the optical transmission is shown to be consistent with the design expectations.

astro-ph.IM↗

arXiv2015

The Mid-Infrared Instrument for JWST, II: Design and Build

The Mid-InfraRed Instrument (MIRI) on the James Webb Space Telescope (JWST) provides measurements over the wavelength range 5 to 28.5 microns. MIRI has, within a single 'package', four key scientific functions: photometric imaging, coronagraphy, single-source low-spectral resolving power (R ~ 100) spectroscopy, and medium-resolving power (R ~ 1500 to 3500) integral field spectroscopy. An associated cooler system maintains MIRI at its operating temperature of < 6.7 K. This paper describes the driving principles behind the design of MIRI, the primary design parameters, and their realization in terms of the 'as-built' instrument. It also describes the test program that led to delivery of the tested and calibrated Flight Model to NASA in 2012, and the confirmation after delivery of the key interface requirements.

astro-ph.IM↗

arXiv2006

A multi-object, multi-field spectrometer and imager for a European ELT

One of the highlights of the European ELT Science Case book is the study of resolved stellar populations, potentially out to the Virgo Cluster of galaxies. A European ELT would enable such studies in a wide range of unexplored distant environments, in terms of both galaxy morphology and metallicity. As part of a small study, a revised science case has been used to shape the conceptual design of a multi-object, multi-field spectrometer and imager (MOMSI). Here we present an overview of some key science drivers, and how to achieve these with elements such as multiplex, AO-correction, pick-off technology and spectral resolution.

astro-ph↗

arXiv2002

Multiple Integral Field Spectroscopy

Integral-field spectroscopy is the most effective method of exploiting the superb image quality of the ESO-VLT, allowing complex astrophysical processes to be probed on the angular scales currently accessible only for imaging data, but with the addition of information in the spectral dimension. We discuss science drivers and requirements for multiple deployable integral fields for spectroscopy in the near-infrared. We then describe a fully modular instrument concept which can achieve such a capability over a 5-10' field with up to 32 deployable integral fields, each fully cryogenic with 1-2.5 micron coverage at a spectral resolution of ~3000, each with a 4" x 4" field of view sampled at 0.2"/pixel to take advantage of the best K-band seeing.

astro-ph↗