6 research outputs found
DMRadio-m: A Search for the QCD Axion Below eV
The QCD axion is one of the most compelling candidates to explain the dark
matter abundance of the universe. With its extremely small mass (), axion dark matter interacts as a classical field rather
than a particle. Its coupling to photons leads to a modification of Maxwell's
equations that can be measured with extremely sensitive readout circuits.
DMRadio-m is a next-generation search for axion dark matter below
eV using a T static magnetic field, a coaxial inductive pickup, a
tunable LC resonator, and a DC-SQUID readout. It is designed to search for QCD
axion dark matter over the range (). The primary
science goal aims to achieve DFSZ sensitivity above neV (30
MHz), with a secondary science goal of probing KSVZ axions down to
(10 MHz).Comment: 8 pages, 4 figures. Updated to fix small errors and correct
acknowledgement
Using SQUIDs to Detect Charge in Cryogenic Germanium Detectors
This paper describes an impedance matching network which allows charge impulses to be measured by a SQUID amplifier with an RMS charge noise of less than 100 e, assuming the SQUID amplifier has a current noise of 2 pA/√Hz, and the current pulse has a duration of about 1 μs or shorter. The component values are provided for an example system which has an RMS charge noise of 91 e, assuming all dissipative circuit elements are cooled to a temperature of 100 mK
Spatial Imaging of Charge Transport in Germanium at Low Temperature
The purpose of this experiment is to observe the oblique propagation of electrons through germanium by exciting a point source of charge carriers with a focused laser pulse on one face of a germanium crystal. After the electrons are drifted through the crystal by a uniform electric field, the pattern of charge density arriving on the opposite face is mapped and used to reconstruct the trajectories of the electrons. These measurements will verify in detail the Monte Carlo analysis utilized in the Cryogenic Dark Matter Search to model the transport of charge carriers in high-purity germanium detectors, including both oblique electron propagation and inter-valley scattering
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Proposal for a definitive search for GUT-scale QCD axions
The QCD axion is a leading dark matter candidate that emerges as part of the solution to the strong CP problem in the Standard Model. The coupling of the axion to photons is the most common experimental probe, but much parameter space remains unexplored. The coupling of the QCD axion to the Standard Model scales linearly with the axion mass; therefore, the highly motivated region 0.4-120 neV, corresponding to a GUT-scale axion, is particularly difficult to reach. This paper presents the design requirements for a definitive search for GUT-scale axions and reviews the technological advances needed to enable this program