First Observation of Cyclotron Radiation from MeV-Scale e^{±} following Nuclear β Decay.

Area of Science:

• Nuclear Physics
• Particle Physics
• Spectroscopy

Background:

• Precise measurement of beta decay properties is crucial for understanding fundamental physics.
• The cyclotron radiation emission spectroscopy (CRES) technique has shown promise for low-energy beta decays.
• Extending CRES to higher energies is essential for broader applications in nuclear physics and beyond.

Purpose of the Study:

• To present a novel apparatus for detecting cyclotron radiation from beta particles.
• To determine the kinetic energy of beta particles (β±) in the 5 keV to 2.1 MeV range.
• To establish the foundation for applying CRES to a wider range of nuclear decays and energies.

Main Methods:

• Utilized a frequency-based determination of beta particle kinetic energy via their cyclotron frequency in a magnetic field.
• Demonstrated the broadband response of the detection system using beta decays from Helium-6 (⁶He) and Neon-19 (¹⁹Ne).
• Assessed potential systematic uncertainties for beta spectroscopy across the MeV energy range.

Main Results:

• Successfully detected cyclotron radiation from individual highly relativistic beta particles in a waveguide.
• Achieved precise kinetic energy determination for beta particles from 5 keV to 2.1 MeV.
• Demonstrated the capability of the apparatus for broadband beta spectroscopy beyond the tritium energy endpoint.

Conclusions:

• The developed apparatus and CRES technique are effective for precise beta spectroscopy over an extended energy range.
• This work opens new avenues for applying CRES to various nuclei and searching for new physics beyond the Standard Model.
• The ability to perform precision beta-decay measurements at higher energies has significant implications for fundamental physics research.