Cavity Ring-Down

Cavity Ring-Down setups for gas-phase measurements

The cavity ring-down technqiue can be used to measure weak transitions of molecules in the gas phase, or probe trace gases, or low-abundant isotopic species. At LCVU several setups are available to perform such studies over a wide wavelength range. Pulsed tunable lasers are avaliable, covering the entire wavelength range between 200 and 900 nm to be employed in gas-phase CRD; similarly a wide range of CRD-mirrors with highly reflective coatings is available.

A special cell has been designed to perfrom so-called pressure ramp CRD studies to extract low extinction cross sections, such as e.g. the Rayleigh cross section. The cell exhibits arrays of inlet holes to allow for turbulance-free pressure ramping a cell up to pressure of 1 Bar (picture left). pr-cavity

discharge

In addition to pressure ramps and static gas measurements we have als available a slit-discharge nozzle setup (picture on the right) to perform CRD-absorption measurements along a slit, where the discharge provides the formation of short-lived radical species and ions in the gas phase.
Contact Person at LCVU: Wim Ubachs, email: wimu@nat.vu.nl