CDI Capability: Radiotracer Atmospheric Dynamics Chamber

Unique environmental chamber enables researchers to investigate interconversions of radiolabeled molecules in the gas phase

The custom-built environmental chamber allows monitoring of the interconversion of molecules in the gas phase under controlled conditions of pressure, temperature, humidity, and the presence of other trace species via reactions initiated by sunlight photolysis. An integrated sensor array provides in situ measurement of the concentrations of molecular species as the reactions proceed.

Radiotracer Atmospheric Chamber
Atmospheric dynamics chamber showing sensor array and temperature control manifold (Image by Andrea Starr | Pacific Northwest National Laboratory)

Radiotracer atmospheric dynamics chamber for the study of photolysis chemistry initiated by sunlight

The custom-built atmospheric chamber is designed to handle both cold and radioactive species to investigate the fundamental chemical kinetics of molecular transformations under controlled conditions representative of the troposphere. The use of radioactive tracers provides an extension of the chamber for advanced tracking of complex chemical transformations. The chamber closely controls atmospheric conditions of temperature, pressure, humidity, trace gas concentration, and ultraviolet irradiation (via a xenon lamp solar simulator) combined with an integrated sensor array recording humidity, ozone, and NOx concentrations with further monitoring of concentrations using an attached gas chromatograph electron capture detector (GC-ECD). Additional chamber connections provide extracting samples for ex situ characterization using gas chromatography–mass spectrometry and single particle mass spectroscopy to further characterize the reaction mechanism.  

Main specifications:

  • volume: 1.1 cubic meters
  • solar simulator: 2.5 kW Xe lamp, 920-840 W/m2, 82% of solar spectrum in the 600-800nm range, 114% of solar spectrum in the ultraviolet range, additional intensity control with filters
  • air purification system: removes hydrocarbons, NOx, moisture, CO2
  • mass flow controllers for introduction of gases: CO2, NOx, bottle gases, water
  • fume hood injection system for reactive gases
  • gas sensors: humidity, ozone, NOx
  • detection limits of gas sensor array and GC-ECD: 1-2 ppb
  • temperature range: -10oC to 60oC
  • pressure range: 0.1 mTorr (scroll pump) to 680 Torr
  • inner SilcoTek 2000 surface treatment to reduce wall losses

Research topics

Radiological & Nuclear Detection