Large-format X-Ray Reflection Grating Operated in an Echelle-like Mounting

Holographically-formed X-ray reflection grating scan now be constructed with competitive groove efficiency to classically ruled types, down to a short wavelength diffracting limit of several angstroms.The gratings can be generated on any surface capable of intersecting the interference fringe pattern without shadowing. This fact alone brings several new X-ray optical design possibilities within reach, for example, by combining plane construction waves with steep aspheric substrates. The first order imaging theory of the grazing incidence mounting is discussed and compared to measured performance for aberration corrected stigmatic types.A new 5 meter spectrograph has also been constructed with applications in molecular chemistry, laser fusion research and synchro tronspectroscopy. The unit is available with fully prefocussed holographic and classical X-ray grating optics, and uses the precision miniature camera principle of fully interchangeable lenses, but applied, in this case to the entrance slit, grating and detector modules.

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Performance Testing of a Large-Format X-ray Reflection Grating Prototype for a Suborbital Rocket Payload

Journal of Astronomical Instrumentation ◽

10.1142/s2251171720500178 ◽

2020 ◽

Vol 09 (04) ◽

pp. 2050017

Author(s):

Benjamin D. Donovan ◽

Randall L. McEntaffer ◽

Casey T. DeRoo ◽

James H. Tutt ◽

Fabien Grisé ◽

...

Keyword(s):

Probability Distribution ◽

Confidence Level ◽

Posterior Probability ◽

Performance Testing ◽

Test Facility ◽

Finite Limit ◽

Max Planck ◽

X Ray ◽

Posterior Probability Distribution ◽

Reflection Grating

The soft X-ray grating spectrometer on board the Off-plane Grating Rocket Experiment (OGRE) hopes to achieve the highest resolution soft X-ray spectrum of an astrophysical object when it is launched via suborbital rocket. Paramount to the success of the spectrometer are the performance of the [Formula: see text] reflection gratings populating its reflection grating assembly. To test current grating fabrication capabilities, a grating prototype for the payload was fabricated via electron-beam lithography at The Pennsylvania State University’s Materials Research Institute and was subsequently tested for performance at Max Planck Institute for Extraterrestrial Physics’ PANTER X-ray Test Facility. Bayesian modeling of the resulting data via Markov chain Monte Carlo (MCMC) sampling indicated that the grating achieved the OGRE single-grating resolution requirement of [Formula: see text] at the 94% confidence level. The resulting [Formula: see text] posterior probability distribution suggests that this confidence level is likely a conservative estimate though, since only a finite [Formula: see text] parameter space was sampled and the model could not constrain the upper bound of [Formula: see text] to less than infinity. Raytrace simulations of the tested system found that the observed data can be reproduced with a grating performing at [Formula: see text]. It is therefore postulated that the behavior of the obtained [Formula: see text] posterior probability distribution can be explained by a finite measurement limit of the system and not a finite limit on [Formula: see text]. Implications of these results and improvements to the test setup are discussed.

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