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

W Byron; H Harrington; R J Taylor; W DeGraw; N Buzinsky; B Dodson; M Fertl; A García; G Garvey; B Graner; M Guigue; L Hayen; X Huyan; K S Khaw; K Knutsen; D McClain; D Melconian; P Müller; E Novitski; N S Oblath; R G H Robertson; G Rybka; G Savard; E Smith; D D Stancil; M Sternberg; D W Storm; H E Swanson; J R Tedeschi; B A VanDevender; F E Wietfeldt; A R Young; X Zhu; He6-CRES Collaboration

doi:10.1103/PhysRevLett.131.082502

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

Phys Rev Lett. 2023 Aug 25;131(8):082502. doi: 10.1103/PhysRevLett.131.082502.

Authors

W Byron^{1

2}, H Harrington^{1

2}, R J Taylor^{3

4}, W DeGraw^{1

2}, N Buzinsky^{1

2}, B Dodson^{1

2}, M Fertl⁵, A García^{1

2}, G Garvey^{1

2}, B Graner^{1

2}, M Guigue⁶, L Hayen^{3

4}, X Huyan⁶, K S Khaw^{1

2}, K Knutsen^{1

2}, D McClain^{7

8}, D Melconian^{7

8}, P Müller⁹, E Novitski^{1

2}, N S Oblath⁶, R G H Robertson^{1

2}, G Rybka^{1

2}, G Savard⁹, E Smith^{1

2}, D D Stancil¹⁰, M Sternberg^{1

2}, D W Storm^{1

2}, H E Swanson^{1

2}, J R Tedeschi⁶, B A VanDevender^{1

6}, F E Wietfeldt¹¹, A R Young^{3

4}, X Zhu^{1

2}; He6-CRES Collaboration

Affiliations

¹ Department of Physics, University of Washington, Seattle, Washington 98195, USA.
² Center for Nuclear Physics and Astrophysics, University of Washington, Seattle, Washington 98195, USA.
³ Physics Department, North Carolina State University, Raleigh, North Carolina 27695, USA.
⁴ The Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA.
⁵ Institute for Physics, Johannes-Gutenberg University Mainz, 55128 Mainz, Germany.
⁶ Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
⁷ Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843, USA.
⁸ Cyclotron Institute, Texas A&M University, College Station, Texas 77843, USA.
⁹ Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
¹⁰ Department of Electrical and Computer Engineering, North Carolina State University, Raleigh, North Carolina 27695, USA.
¹¹ Department of Physics and Engineering Physics, Tulane University, New Orleans, Louisiana 70118, USA.

PMID: 37683153
DOI: 10.1103/PhysRevLett.131.082502

Abstract

We present an apparatus for detection of cyclotron radiation yielding a frequency-based β^{±} kinetic energy determination in the 5 keV to 2.1 MeV range, characteristic of nuclear β decays. The cyclotron frequency of the radiating β particles in a magnetic field is used to determine the β energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 Collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of β^{-}'s from ^{6}He and β^{+}'s from ^{19}Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for β spectroscopy over the full (MeV) energy range. To our knowledge, this is the first direct observation of cyclotron radiation from individual highly relativistic β's in a waveguide. This work establishes the application of CRES to a variety of nuclei, opening its reach to searches for new physics beyond the TeV scale via precision β-decay measurements.