ANAIS is an experiment developed by the Nuclear and Astroparticle Physics group of the University of Zaragoza which pursues this elusive dark matter detection by looking at the annual modulation of the expected interaction rates in a target of sodium iodide, material which produces small scintillations when a particle interacts and deposits some energy. This modulation is a distinctive feature stemming from the Earth revolution around the Sun which changes periodically the relative velocity of the incoming Dark Matter particles to the detector and, because of that, the energy deposited. DAMA-LIBRA experiment at Gran Sasso Underground Laboratory has reported the presence of modulation in its data with a high statistical significance; ANAIS could confirm it and help to understand the different systematics involved.
ANAIS is the large scale conclusion of previous studies carried out with different prototypes by the University of Zaragoza group at the Canfranc Underground Laboratory, Spain. ANAIS-112 is using 112.5 kg of NaI(Tl) crystals to study the expected annual modulation in the galactic dark matter signal distributed in 9 modules of 12.5 kg each.
ANAIS-112 is taking data at the Canfranc Underground Laboratory since 3 August 2017. In 2019 first results, corresponding to 1.5 years of data, and in 2021 the results of 3 years were published. They are compatible with the absence of modulation and incompatible with the DAMA/LIBRA positive modulation with a sensitivity of 2.5-2.7 sigma for the 3 years result, confirming the sensitivity estimates. DAMA/LIBRA result is at reach with 3 sigmas of significance in 5 years of data. Recently, the sensitivity has been improved by developing a new machine-learning event selection protocol. This improvement will allow testing DAMA/LIBRA with 3 sigmas of significance with the first 3 years of data.
We list here the available datasets from the ANAIS experiment. The data can be downloaded for use or dynamically visualised within the repository. Please note the appropriate sources listed for citation when using data from the ANAIS Collaboration.