Since neutrino oscillation experiments observed the oscillation which is the evidence of non-zero neutrino mass, the neutrino mass has been the hot issue in particle physics field. A search for a neutrinoless double beta (0-nu-beta-beta) decay search is the promising experimental approach to estimate an absolute mass of neutrino and its nature (Dirac or Majorana). The 0-nu-beta-beta decay is forbidden in the Standard Model (SM) due to the lepton number conservation and its observation will be an evidence for new physics beyond the SM.
There are several experimental groups to search 0-nu-beta-beta decay using various candidate isotopes such as 48Ca, 76Ge, 82Se, 100Mo, 116Cd, 128Te, 130Te, 136Xe, 150Ne and etc. Among the isotopes, 100Mo is one of the promising candidate due to its relatively higher Q-value (3.034 MeV) and higher natural abundance (9.6% in nature). In addition, 100Mo can be a detector itself in a CaMoO4 scintillation crystal form. However, the CaMoO4 scintillation crystal has a two-neutrino double beta (2-nu-beta-beta) decay candidate isotope, 48Ca with 4.3 MeV of Q-value. We developed 40Ca100MoO4 scintillation crystals to reduce internal backgrounds from 2-nu-beta-beta decay of 48Ca and increase the effective mass of the 100Mo. The scintillation properties and internal background level of 238U and 232Th to measure the levels of 214Bi and 208Tl, which are major background on 3 MeV.
This thesis presents the growing process, measurements of the scintillation properties of 40Ca100MoO4 scintillation crystals and internal background measurement by using 4pi gamma veto system. The preliminary result for sensitivity of the 0-nu-beta-beta decay of 100Mo and prospects of AMoRE (Advanced Molybdenum based rare process Experiment) collaboration are also presented.
Thesis Advisor: Prof. Hongjoo Kim