An electroluminescence emission detector to search for positron double-beta decays of 124Xe and of 78Kr

An emission detector, self-triggered with scintillation, is proposed to search for positron double-beta decays of ¹²⁴Xe and of ⁷⁸Kr. Ionisation clusters are extracted from liquid phase and measured with matrix of photodetectors as electroluminescent flashes of the gas phase. In case of 2β⁺ decay, a useful event will contain 5 ionisation clusters, cross-laying in the same plane. In case of Kβ⁺ decay, a useful event will contain 3 clusters, laying in the same line. Proposed detector with 0.4 m³ working volume will be able to check the theoretical prediction for T_1/2 of 2β⁺2ν and Kβ⁺2ν decays of ¹²⁴Xe isotope in over-ground experiment and of 2β^-0ν, 2β^- 2ν decays of ¹³⁴Xe, ¹³⁶Xe isotopes in underground experiment with natural mixture of Xe isotopes. Seeking for 2β⁺0ν, 2β⁺2ν, Kβ⁺0ν and Kβ⁺2ν decays of ⁷⁸ Kr in over-ground experiment with natural mixture of isotopes is also possible with additional NaI(Tl) triggering system surrounding the emission detector. High pressure Xe gas-filled model of the emission detector with working volume of 40 cm diameter and 4 cm depth is built and tested with multi-clusters events generated by absorbing γ-radiation