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Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry
Published on: August 1, 2017
Soft-x-ray generation in a helium environment using laser-produced plasmas.
Optics Letters
|September 1, 2009
Summary
Soft-x-ray generation using a laser on a steel target is minimally affected by helium gas pressure up to 100 mbar. The X-ray emission duration closely matches the laser pulse duration.
Area of Science:
- Physics
- Plasma Physics
- Laser-Induced Breakdown Spectroscopy (LIBS)
Background:
- Soft-x-ray radiation is crucial for various applications, including lithography and materials analysis.
- Understanding the influence of ambient gas on laser-produced plasma (LPP) emission is vital for optimizing X-ray generation.
Purpose of the Study:
- To investigate the effect of helium gas pressure on soft-x-ray emission from a laser-produced plasma.
- To characterize the temporal properties of soft-x-ray emission in relation to laser pulse duration.
Main Methods:
- Focused a Q-switched Nd:glass laser beam onto a steel target within a helium-filled chamber.
- Varied helium gas pressures from 10⁻⁵ mbar to 500 mbar.
- Detected soft-x-ray radiation (λ ≤ 1.5 nm) using a P-I-N diode filtered by a 25-μm Beryllium foil.
Main Results:
- Soft-x-ray emission decreased by less than 10% for helium pressures below 100 mbar compared to high-vacuum conditions.
- The half-width of the soft-x-ray emission pulse (τx-ray) was independent of helium pressure.
- τx-ray was comparable to the laser pulse half-width (τLASER ≈ 17 nsec).
Conclusions:
- Helium gas pressures below 100 mbar have a negligible impact on soft-x-ray emission intensity from laser-produced plasmas.
- The temporal characteristics of soft-x-ray emission are primarily determined by the laser pulse duration, not the ambient helium pressure.
