University of Illinois Urbana-Champaign

CONSTRUCTION OF A CRYO-COOLED BUFFER GAS CELL FOR PERFORMING BROADBAND CHIRPED-PULSE FOURIER TRANSFORM MICROWAVE (CP-FTMW) SPECTROSCOPY

Welsh, Blair

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7238.pdf
FD04_1.pptx

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https://hdl.handle.net/2142/122690

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Title
CONSTRUCTION OF A CRYO-COOLED BUFFER GAS CELL FOR PERFORMING BROADBAND CHIRPED-PULSE FOURIER TRANSFORM MICROWAVE (CP-FTMW) SPECTROSCOPY
Author(s)
Welsh, Blair
Contributor(s)
  • Zwier, Timothy S.
  • Au, Kendrew
  • Zhang, Angie
Issue Date
2023-06-23
Keyword(s)
Instrument/Technique Demonstration
Abstract
The preparation of rotationally cold molecules through the use of supersonic expansions has long been a mainstay of high-resolution gas-phase microwave spectroscopy[¹]. An increasingly popular alternative to this method is to cool molecules of interest through continuous collisions with a large reservoir of cryogenic, inert buffer gas, typically helium[²]. This offers several advantages over pulsed supersonic jet methods, namely higher data acquisition rates, higher sample throughput and lower electronics noise. We report the construction of such a cryo-cooled buffer gas cell at the Combustion Research Facility at Sandia National Laboratories in California. The instrument has been designed to perform broadband chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy across a frequency range of 6 to 18 GHz. A cooling capacity of 2.7 W at 4 K has been leveraged in order to accommodate a broad range of source assemblies and their associated heat loads, including flash pyrolysis reactors heated up to ∼ 1600 ◦C. Interleaved, perforated radiation shielding has been employed in concert with a hybrid cryopump/turbopump regime in an effort to reduce the frequency of degenerative thermal “crashes” that often plague such instruments. The performance of the instrument with respect to benchmark species will be discussed, as well as the future of the instrument and its experimental endeavors.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/122690
DOI
https://doi.org/10.15278/isms.2023.7238

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Abstracts & Presentations - 2023 International Symposium on Molecular Spectroscopy PRIMARY