— A cryogenic source of polarized deuterium atoms is described. This source is used in the experiment on measuring the analyzing powers in the deuteron photodisintegration reaction at the VEPP-3 electron storage ring at the Budker Institute of Nuclear Physics. The efficiency has been measured for atomic transitions to a specified energy state in the medium field transition (MFT) unit, in the strong field transition (SFT) unit, and for joint operation of these units. A Lamb shift polarimeter was used in the measurements. The measured efficiency of the units is over 90%. The procedure for determining the background in the polarimeter is presented. The use of pumping in the ionizer chamber is expected to significantly reduce the background signal.