Muonic atom spectroscopy with microgram target material

Area of Science:

• Nuclear Physics
• Atomic Physics
• Spectroscopy

Background:

• Muonic atom spectroscopy is a powerful technique for determining nuclear charge radii with high accuracy.
• Traditional methods require substantial target material (hundreds of milligrams) due to the need to stop muon beams directly.
• This limitation restricts the application of muonic atom spectroscopy to elements available in sufficient quantities.

Purpose of the Study:

• To develop a new, more efficient method for muonic atom spectroscopy.
• To significantly reduce the amount of target material required for muonic atom spectroscopy measurements.
• To enable high-precision nuclear structure studies on a wider range of elements.

Main Methods:

• A novel technique employing repeated transfer reactions within a high-pressure (100 bar) hydrogen gas cell with a deuterium admixture (0.25%) was developed.
• Detailed simulations of the transfer reaction dynamics were performed and validated against experimental data.
• The method was demonstrated by measuring 2p-1s muonic x rays from a 5 µg gold target.

Main Results:

• The new method drastically reduces the necessary target material to microgram quantities while maintaining adequate efficiency.
• Simulations accurately reproduced experimental data, confirming a good understanding of the underlying transfer reaction processes.
• Successful proof-of-principle measurement achieved using a minimal gold target.

Conclusions:

• The developed method overcomes the material limitations of traditional muonic atom spectroscopy.
• This technique opens new avenues for precise nuclear charge radius measurements, particularly for rare or low-abundant isotopes.
• The findings pave the way for broader applications of muonic atom spectroscopy in nuclear structure and fundamental physics.