Design and Implementation of the ABRACADABRA-10 cm Axion Dark Matter Search

The past few years have seen a renewed interest in the search for light particle dark matter. ABRACADABRA is a new experimental program to search for axion dark matter over a broad range of masses, $10^{-12}\lesssim m_a\lesssim10^{-6}$ eV. ABRACADABRA-10 cm is a small-scale prototype for a future detector that could be sensitive to QCD axion couplings. In this paper, we present the details of the design, construction, and data analysis for the first axion dark matter search with the ABRACADABRA-10 cm detector. We include a detailed discussion of the statistical techniques used to extract the limit from the first result with an emphasis on creating a robust statistical footing for interpreting those limits.Comment: 12 pages, 8 figure

A Ioffe Trap Magnet for the Project 8 Atom Trapping Demonstrator

The goal of the Project 8 experiment (B. Monreal and J. Formaggio, 2009) is to measure the absolute neutrino mass using tritium, which involves precisely measuring the energies of the beta-decay electrons in the high-energy tail of the spectrum (A. A. Esfahani et al., 2017). The experimental installation of Project 8 Atom Trapping Demonstrator requires a magnet with rather unusual field properties. The magnet has to contain within the cold mass a large volume enclosed by a continuous, uninterrupted boundary higher than 2 T, whereas the field in a substantial volume inside this boundary has to be of the order of 10 -4 T or less. A 1-T solenoid field provides the background field necessary for the detection of the beta-decay electrons (A. A. Esfahani et al., 2019). A proposed toroidal magnet system [a Ioffe-Pritchard trap (T. Bergeman et al., 1987)] comprised of specially shaped multiple racetrack windings with opposing polarities satisfies these unusual requirements. The magnet is made of NbTi wire and expected to be conduction cooled. Manufacturability issues are addressed as well as the effect of tolerances on the field quality. The design includes additional topological features providing a low-field duct for interfacing with the peripheral coils of the velocity and state selector