arXiv subjects

S. H. Yong

Publications and source records attributed to S. H. Yong.

4 recordsLinked to original sources

arXiv2018

Initial performance of the high sensitivity alpha particle detector at the Yangyang underground laboratory

Initial performance of the UltraLo-1800 alpha particle detector at the 700 m deep Yangyang underground laboratory in Korea is described. The ionization detector uses Argon as a counting gas for measuring alpha events of a sample. We present initial calibration results and low-activity sample measurements based on the detector's pulse discrimination method and a hardware veto. A likelihood analysis that shows a separation of a bulk component from a surface component with a contamination depth from $^{210}$Po alpha particles using simulated models is presented.

physics.ins-det↗

arXiv2018

Background model for the NaI(Tl) crystals in COSINE-100

The COSINE-100 dark matter search experiment is an array of NaI(Tl) crystal detectors located in the Yangyang Underground Laboratory (Y2L). To understand measured backgrounds in the NaI(Tl) crystals we have performed Monte Carlo simulations using the Geant4 toolkit and developed background models for each crystal that consider contributions from both internal and external sources, including cosmogenic nuclides. The background models are based on comparisons of measurement data with Monte Carlo simulations that are guided by a campaign of material assays and are used to evaluate backgrounds and identify their sources. The average background level for the six crystals (70 kg total mass) that are studied is 3.5 counts/day/keV/kg in the (2-6) keV energy interval. The dominant contributors in this energy region are found to be $^{210}$Pb and $^3$H.

astro-ph.IM↗

arXiv2018

Initial Performance of the COSINE-100 Experiment

COSINE is a dark matter search experiment based on an array of low background NaI(Tl) crystals located at the Yangyang underground laboratory. The assembly of COSINE-100 was completed in the summer of 2016 and the detector is currently collecting physics quality data aimed at reproducing the DAMA/LIBRA experiment that reported an annual modulation signal. Stable operation has been achieved and will continue for at least two years. Here, we describe the design of COSINE-100, including the shielding arrangement, the configuration of the NaI(Tl) crystal detection elements, the veto systems, and the associated operational systems, and we show the current performance of the experiment.

physics.ins-det↗

arXiv2017

Muon detector for the COSINE-100 experiment

The COSINE-100 dark matter search experiment has started taking physics data with the goal of performing an independent measurement of the annual modulation signal observed by DAMA/LIBRA. A muon detector was constructed by using plastic scintillator panels in the outermost layer of the shield surrounding the COSINE-100 detector. It is used to detect cosmic ray muons in order to understand the impact of the muon annual modulation on dark matter analysis. Assembly and initial performance test of each module have been performed at a ground laboratory. The installation of the detector in Yangyang Underground Laboratory (Y2L) was completed in the summer of 2016. Using three months of data, the muon underground flux was measured to be 328 $\pm$ 1(stat.)$\pm$ 10(syst.) muons/m$^2$/day. In this report, the assembly of the muon detector and the results from the analysis are presented.

physics.ins-det↗