CdWO$_{4}$/CsI and APDs for Low Background Experiments*

Large Area Avalanche Photodiodes (LAAPDs) serve many functions in modern science. CdWO$_{4}$ crystals enable us to detect both neutrinoless double beta decay and geo-neutrinos. CsI crystals can be used to directly detect dark matter. In our study, we will use two APDs coupled to CsI and CdWO$_{4}$ crystals to study neutrons and gamma ray responses. We will report some preliminary results on the discrimination of neutrons and gamma rays. Efforts on stabilizing the temperature and gain will also be described.