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Enhancing radical molecular beams by skimmer cooling
Hao Wu1, David Reens, Tim Langen
1JILA, National Institute of Standards and Technology and the University of Colorado, Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA. Hao.Wu@colorado.edu Dave.Reens@colorado.edu.
Physical Chemistry Chemical Physics : PCCP
|April 17, 2018
Summary
Skimmer clogging in supersonic beams, a challenge in molecular experiments, is overcome by cooling the skimmer. This method enhances radical beam density by 30 times, enabling new research possibilities.
Area of Science:
- Chemical Physics
- Molecular Dynamics
- Spectroscopy
Background:
- Supersonic beams are crucial for molecular collision, chemical reaction, and spectroscopy studies.
- Skimmer clogging limits molecular density in experiments, necessitating large valve-skimmer distances.
- Previous work demonstrated skimmer cooling suppresses clogging for certain gases.
Purpose of the Study:
- To apply and optimize skimmer cooling for discharge-produced radical and metastable beams.
- To investigate mechanisms of skimmer clogging mitigation.
- To significantly enhance molecular beam density for advanced experiments.
Main Methods:
- Cooling skimmers below the carrier gas freezing point to prevent clogging.
- Applying skimmer cooling to radical and metastable beams.
- Optimizing beam production with reduced valve-skimmer distances.
Main Results:
- Identified two clogging mitigation processes: shockwave suppression and diffusive clogging.
- Achieved a 30-fold increase in hydroxyl radical beam density compared to commercial devices.
- Demonstrated effective skimmer cooling for radical and metastable species.
Conclusions:
- Skimmer cooling is a viable strategy for enhancing radical and metastable beam intensity.
- Optimized beam production with reduced valve-skimmer distance significantly boosts molecular density.
- This advancement opens new avenues for high-resolution molecular studies.
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