Conversion efficiency of multi-keV L-shell-band X-ray emission

Area of Science:

• Plasma Physics
• X-ray Science
• Laser-Matter Interaction

Background:

• Efficient generation of multi-kiloelectronvolt (keV) X-rays is crucial for various scientific and technological applications.
• Previous research has explored different target configurations and laser parameters for X-ray production.

Purpose of the Study:

• To investigate the influence of foil thickness, laser pulse width, and laser intensity on multi-keV X-ray conversion efficiency.
• To optimize the performance of sandwiched (CH/Sn/CH) planar targets for X-ray generation.
• To understand the plasma dynamics governing X-ray emission from thin foil targets.

Main Methods:

• Experiments were conducted at the Shenguang II laser facility using sandwiched (CH/Sn/CH) planar targets.
• Laser irradiation parameters (intensity, pulse width) and target foil thickness were systematically varied.
• X-ray photon fields were measured using elliptically bent crystal spectrometers.
• Conversion efficiencies (ξx) for photon energies between 3.7-4.3 keV were determined.

Main Results:

• X-ray yields in the 3.7-4.3 keV range showed strong dependence on laser pulse width, target thickness, and laser intensity.
• Three-layer thin foils demonstrated potential as efficient multi-keV X-ray sources by altering X-ray emission distribution and target dynamics.
• The formation of large, hot, underdense plasma was observed, influencing X-ray output.
• Rarefaction waves from the plasma expansion can suppress X-ray emission if parameters are not optimized.

Conclusions:

• Careful optimization of laser parameters and foil thickness is essential for efficient 3.7-4.3 keV X-ray source development.
• Sandwiched thin foils offer a viable pathway for efficient multi-keV L-shell-band X-ray generation.
• Understanding and mitigating the effects of rarefaction waves are critical for maximizing X-ray yields.