Search of Axions from a Nuclear Power Reactor with a High-Purity Germanium Detector

TL;DR

This study searched for axions emitted from a nuclear reactor using a high-purity germanium detector, setting new constraints on axion properties in the keV to MeV mass range and excluding certain models.

Contribution

First experimental search for reactor-produced axions using germanium detector, establishing new bounds on axion couplings in the keV to MeV mass range.

Findings

No evidence of axion emissions was observed.

Constraints on axion couplings were established for masses between 10^4 eV and 10^6 eV.

Excluded KSVZ and DFSZ axion models within specified mass range.

Abstract

A search of axions produced in nuclear transitions was performed at the Kuo-Sheng Nuclear Power Station with a high-purity germanium detector of mass 1.06 kg at a distance of 28 m from the 2.9 GW reactor core. The expected experimental signatures were mono-energetic lines produced by their Primakoff or Compton conversions at the detector. Based on 459.0/96.3 days of Reactor ON/OFF data, no evidence of axion emissions were observed and constraints on the couplings $\gagg$ and $\gaee$ versus axion mass $m_a$ within the framework of invisible axion models were placed. The KSVZ and DFSZ models can be excluded for 10^4 eV < m_a < 10^6 ~eV. Model-independent constraints on \gagg \gv1 < 7.7 X 10^{-9} GeV^{-2} for m_{a} < 10^5 eV and \gaee \gv1 < 1.3 X 10^{-10} for m_{a} < 10^6 eV at 90% confidence level were derived. This experimental approach provides a unique probe for axion mass at the keV--MeV range not accessible to the other techniques.