Electromagnetic detector for relic axions

Technical Report · Tue May 01 04:00:00 EDT 1984

DOI:https://doi.org/10.2172/6446664· OSTI ID:6446664

Morris, D E

Axions are particles of small mass postulated to explain CP conservation in strong interactions. The predicted properties of axions provide an explanation for the early clustering of matter into galaxies, the mass in galactic halos, and the missing mass sufficient to close the universe. The interaction of axions with ordinary matter would be extremely weak, but axions should be detectable, because in a strong magnetic field relic axions of mass m/sub a/ would convert into microwave photons with frequency f=m/sub a/c/sup 2//h. Predictions for the frequency range from 3 and 24 GHz for relic axions which provide mass density sufficient to close the universe. We propose a laboratory search for relic axions. A specific experimental apparatus is described and system performance is estimated to illustrate the design principles. The microwave signal from axion conversion is produced in a 30 liter microwave cavity which contains dielectric phase shifting plates to give a quality factor (Q) greater than 10/sup 6/, and to provide the correct phasing of the microwave electric field throughout the cavity. The cavity is placed in an 8 Tesla superconducting magnet, and the signal is measured with a conventional microwave receiver employing a GaAs FET rf amplifier or Schottky diode mixer. The cavity, magnet and rf amplifier/mixer will operate at 4/sup 0/K, with noise temperature between 20/sup 0/K and 200/sup 0/K. The system is equally effective in principle at all frequencies between 1 GHz and 100 GHz at which microwave receivers are available. The corresponding range of axion mass which can be covered is 4x10/sup -6/ eV to 4x10/sup -4/ eV. A search can be carried out over an octave of frequency in an observation time of three months with sufficient sensitivity to detect axions if they make up the galactic halo.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6446664
• Report Number(s): LBL-17915; ON: DE85001299
• Country of Publication: United States
• Language: English

Related Subjects

440104* -- Radiation Instrumentation-- High Energy Physics Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AXIONS
BOSONS
CAVITIES
DETECTION
ELECTRICAL EQUIPMENT
ELECTROMAGNETIC RADIATION
ELECTROMAGNETS
ELEMENTARY PARTICLES
EQUIPMENT
GOLDSTONE BOSONS
LOSSES
MAGNETS
MICROWAVE RADIATION
POSTULATED PARTICLES
QUALITY FACTOR
RADIATIONS
SUPERCONDUCTING DEVICES
SUPERCONDUCTING MAGNETS