A reflection-grating spectrometer for extended-source soft-x-ray astronomy
Open Access
- Author:
- Miles, Drew
- Graduate Program:
- Astronomy and Astrophysics
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- July 19, 2021
- Committee Members:
- Abe Falcone, Major Field Member
Miguel Mostafa, Outside Unit & Field Member
John Nousek, Major Field Member
Randy McEntaffer, Chair & Dissertation Advisor
Donald Schneider, Major Field Member
Randy McEntaffer, Professor in Charge/Director of Graduate Studies - Keywords:
- reflection gratings
soft X-ray
diffraction gratings
nanofabrication
diffraction efficiency
grating spectrometer
soft-x-ray astronomy
supernova remnants
cygnus loop
sounding rockets
suborbital rockets
tREXS - Abstract:
- Though the history of X-ray astronomy has included survey instruments with large fields of view (FOVs) and high-resolution instruments capable of resolving distant X-ray sources, a soft-X-ray spectrometer with a moderate field-of-view, ≈1 deg$^2$, and moderate spectral resolution, R ≈ 100, has not yet been realized. Such an instrument can be used to better resolve the emission mechanisms that produce soft X-rays in extended sources and further constrain the diffuse nature of the pervasive soft-X-ray background. Advancements in modern X-ray reflection grating technology have made it possible to observe sources of diffuse soft-X-ray emission with a grating spectrometer capable of unprecedented spectral resolution over large FOVs. This dissertation discusses the applicability and design of a reflection-grating spectrometer intended to observe diffuse soft-X-ray emission from astronomical sources, as well as the fabrication and diffraction efficiency testing of state-of-the-art X-ray reflection gratings. The unprecedented diffraction efficiency achievable with blazed reflection gratings fabricated via electron-beam lithography and various blazing techniques allows for a spectrograph that can obtain new, moderate-resolution spectra from diffuse soft-X-ray sources from a sounding rocket payload: the Rockets for Extended-source X-ray Spectroscopy (tREXS). The tREXS design is presented along with a discussion of the expected significance of the instrument's upcoming observation of the Cygnus Loop supernova remnant. Instrument simulations indicate that tREXS will achieve a more highly-resolved spectrum of Cygnus Loop X-ray emission over a larger FOV than any previous instrument, while providing a template for other potential applications of a grating-based spectrometer for diffuse soft-X-ray emission.