In the Flame Chemistry and Diagnostics Laboratory, Nils Hansen uses state-of-the art tools, including a molecular-beam sampling mass spectrometer (MBMS), to investigate the chemistry of low-pressure, laminar flames. The MBMS instrument combines a time-of-flight (TOF) mass spectrometer with single-photon, vacuum ultraviolet (VUV) photoionization and a quadrupole mass spectrometer with electron-impact ionization. Single-photon, near-threshold ionization provides a means to minimize the formation of fragment ions, while identifying species by their ionization threshold and mass. The system is also compatible with resonance-enhanced multiphoton ionization (REMPI) where higher selectivity is required. The TOF-MS has an optional imaging detector to discriminate further between parent and fragment ions based on spatial ion patterns.

Recently, a team of researchers from the CRF, Cornell University, and the University of Massachusetts constructed another MBMS machine at the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory. This machine uses the tunable vacuum-ultraviolet output from the ALS synchrotron to effect the single-photon ionization of the sampled flame species.

The unparalleled brightness and easy tunability of the ALS source permits thorough characterization of flames in a fraction of the time needed for a laser-based system, and allows straightforward determination of isomers from photoionization efficiency curves. For example, using this extremely powerful apparatus, isomers of C₃H₂, C₄H₃, and C₄H₅ have been identified, and an entire class of molecules ó the enols ó was detected for the first time in flames.