New source of dense, cryogenic positron plasmas

Area of Science:

• Plasma Physics
• Atomic and Molecular Physics
• Cryogenic Engineering

Background:

• Positron plasmas are crucial for fundamental physics research and applications.
• Previous methods for creating dense positron plasmas were limited by accumulation rates and achievable densities.
• Cryogenic environments offer advantages for plasma confinement and stability.

Purpose of the Study:

• To develop and demonstrate a novel method for producing large and dense positron plasmas.
• To significantly improve positron accumulation rates in a cryogenic environment.
• To achieve higher plasma densities than previously reported.

Main Methods:

• Ballistic transfer of pre-accumulated plasmas from a low-field, high-pressure region to a high-field, cryogenic Penning-Malmberg trap.
• Utilizing a 15 K cryogenic environment with a base pressure below 10(-13) mbar and a 3 T magnetic field.
• Employing a rotating wall electric field for plasma compression.

Main Results:

• Achieved positron accumulation rates over 1.5 orders of magnitude higher than previous UHV-compatible methods.
• Successfully created a plasma containing over 1.2 x 10(9) positrons, a fourfold increase.
• Compressed plasmas to a density of 2.6 x 10(10) cm(-3), a sixfold improvement using rotating wall techniques.

Conclusions:

• The developed ballistic transfer method is highly effective for generating large and dense positron plasmas.
• The cryogenic environment and high magnetic field are critical for enhanced performance.
• This advancement opens new possibilities for precision measurements and experiments using positron plasmas.