Reducing current noise in cryogenic experiments by vacuum-insulated cables

摘要

We measure the current noise of several cryogenic cables in a pulse tubebased dilution refrigerator at frequencies between about 1~mHz and 50~kHz. Weshow that vibration-induced noise can be efficiently suppressed by usingvacuum-insulated cables between room temperature and the 2nd pulse tube stage.A noise peak below 4 fA at the 1.4~Hz operation frequency of the pulse tube,and a white noise density of 0.44 fA/\sqrt{Hz} in the millihertz range areobtained.