requirements for combustion kinetics studies at jlab craig a. taatjes, david l. osborn, leonid sheps

Requirements for Combustion Kinetics Studies at JLab

Craig A. Taatjes, David L. Osborn, Leonid Sheps

Photon Beam Requirements

• Tunability– Require photon energies from ~ 6 eV to ~16 eV, depending on

the specific target – Continuous tunability is important for species quantification– Piecewise-continuous or partial coverage is less desirable

• Energy bandwidth – Energy bandwidth of 25 meV is sufficient – Probably need to separate fundamental, higher harmonics out

• High average power, low peak intensity– Keep peak intensity less than ~ 500 kW / cm2 – Collimated beam, diameter <~ 2 mm if possible

Requirements for Experimental Hall

• Footprint of reaction chamber– Also need cart with excimer laser– Pumps with exhaust: scroll pumps backing turbos, roots blower

for reactor– Associated computer equipment

• Chemical handling – toxic gases – excimer gases, Cl2, NO2

– toxic liquids delivered from bubblers– flammable gases

• No extraordinary power and water requirements– Water cooling for turbos and excimer– 208 3-phase for excimer ?

Connection to Beamline

Laser cart is 34.5 x 49 inches, 100 inches high

Orthogonal Extraction Time-of-Flight

Coles and Guilhaus, Trends in Analytical Chemistry, 12, 203 (1993).

Sandia OA-TOF

continuous ion optics

differential-pumping wall

orthogonalextractor

Photon and Ion Beam Paths

0.25 inch between repeller and extractor

2 mm apertures in repeller and extractor

~2 mm is maximum useful photon beam diameter (smaller is better for mass resolution)