COSINE-100 is a joint effort between the DM-Ice and KIMS collaborations to search for dark matter interactions in NaI(Tl) scintillating crystals. The experimental site is located at Yangyang underground laboratory (Y2L), situated at Yangyang pumped storage power plant, with ~700 m of rock overburden. In addition to the COSINE-100 experiments, Y2L is home to the KIMS-CsI and AMoRE experiments.
The first phase of the experiment consists of 8 NaI(Tl) crystals with each optically coupled to two photomultiplier tubes (PMTs). The crystals have nearly the purity of DAMA’s crystals, and they will be submerged into ~2000 liters of liquid scintillator. Liquid scintillator will help to reduce low energy background, mainly coming from radioactive potassium, which is crucial for annual modulation analysis.
The shielding structure of COSINE-100 includes 3 cm of copper, 20 cm of lead, and 3 cm of 37 plastic scintillator panels for cosmic ray muon tagging. 18 5-inch PMTs are attached to the copper box to observe scintillation light from liquid scintillator, and each plastic scintillator has a 2-inch PMT attached on one side (top panels have a PMT on each side).
With careful analysis, comparable energy threshold and background control similar to DAMA experiment, COSINE-100 is expected to have comparable sensitivity with the DAMA allowed region with 2 years of data. COSINE-100 has started taking physics data on September 2016, so stay tuned for our first physics result!