Looking for Hidden Photon's Cold Dark Matter By Multi-Cathode Counter

The dark rate of single-electrons emitted from a cathode of a multi-cathode counter may be interpreted as the effect from Hidden Photons (HPs) of Cold Dark Matter (CDM). As a tentative approach the measurements have been performed at different temperatures of the counter. Preliminary results of measurements by using a counter with a copper cathode are presented. An upper limit of 4.3x10-23 for parameter ksi^2 at 2 sigma has been obtained for hypothetical conversion of hidden photon to real photon at the metallic surface with the resulting emission of single electron. The work is considered as a pure illustration of the method and the perspectives are discussed for future search of HPs by a multi-cathode counter.