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We present experimental results for the ionization of aniline and benzene molecules subjected to intense ultrashort laser pulses. Measured parent molecular ions yields were obtained using a recently developed technique capable of three-dimensional imaging of ion distributions within the focus of a laser beam. By selecting ions originating from the central region of the focus, where the spatial intensity distribution is nearly uniform, volumetric-free intensity-dependent ionization yields were obtained. The measured data revealed a previously unseen resonance-enhanced multiphoton ionization (REMPI)-like process. Comparison of benzene, aniline, and Xe ion yields demonstrates that the observed intensity-dependent structures are not due to geometric artifacts in the focus. Finally for intensities greater than ∼3 × 10 13 W/cm 2 , we attribute the ionization of aniline to a stepwise process going through the πσ * state which sits three photons above the ground state and two photons below the continuum.

Tracer technology is very popular in petroleum engineering applications, and includes applications in reservoir characterization, reservoir modeling, improved oil recovery, etc. Most of the current tracer technology uses radioactive isotopes that are not environmentally friendly and require strict safety precautions. We propose the use of rare long-lived and stable noble gas isotopes as tracers, where instead of the decay of the radioactive material, we will use optical detection. Due to their chemical inertness, rare noble gases offer the advantage that they do not react with the environment with which they are in contact. Our research employs for the first time optical detection of tracers by collinear fast beam laser spectroscopy. It has the additional advantage that novel tracer projects based on multiple tracers can be designed in the future. In this work also the optical hyperfine structure of long lived Kr 85 was used to identify the Kr 85 tracer atoms. The technique has also been successfully applied to stable krypton isotopes. The abundance selectivity is at the one part in 10 10 level and the sensitivity is at a few hundred ions. This method is several orders of magnitude more sensitive than the standard nuclear decay detection. The new tracer technology offers a safer and more accurate option for applications in the oil and gas industry. The research work is currently being done in Qatar for application in Qatar's North Field.

A portable apparatus for the separation of krypton from environmental air samples was tested. The apparatus is based on the cryogenic trapping of gases at liquid nitrogen temperature followed by controlled releases at higher temperatures. The setup consists of a liquid nitrogen trap for the removal of H 2 O and CO 2 , followed by charcoal-filled coils that sequentially collect and release krypton and other gases providing four stages of gas chromatography to achieve separation and purification of krypton from mainly N 2 , O 2 , and Ar. Residual reactive gases remaining after the final stage of chromatography are removed with a hot Ti sponge getter. A thermal conductivity detector is used to monitor the characteristic elution times of the various components of condensed gases in the traps during step-wise warming of the traps from liquid nitrogen temperatures to 0°C, and then to 100°C. This allows optimizing the switching times of the valves between the stages of gas chromatography so that mainly krypton is selected and loaded to the next stage while exhausting the other gases using a He carrier. A krypton separation efficiency of~80 % was determined using a quadrupole mass spectrometer.

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