In this research, we characterized magnetic and electromagnetic interferences of a two-stage pulse tube cryocooler to a LTc SQUID attached directly to the cold stage of the cryocooler and found the noise sources and proposed methods to reduce their interference on the operation of the LTc SQUID. In chapter one an introduction to cryocoolers and cryocooler based SQUID systems is given. Chapter two presents our method to measure the conducted high frequency electromagnetic interference into the cryocooler cold head via noise paths. In chapter three characterization of low frequency magnetic...