Nitrogen Cryogenic System for the Future NICA Accelerator Complex at JINR

The new NICA (Nuclotron-based Ion Collider fAcility) accelerator complex is scheduled to put into operation in 2017 at JINR in Dubna. This facility comprising the existing Nuclotron together with two newly created superconducting accelerators - booster and collider - will require additional refrigeration capacity at 4.5 K and 80 K. The helium cryogenic system of the NICA complex will be created as a result of the modernization of the existing equipment for cryogenic supply of the Nuclotron, but the liquid nitrogen plant will be completely new. It will be based on a 1300 kg/h nitrogen liquefier and two 500 kg/h re-condensers of nitrogen vapor. This report describes the schematic diagram of the system of liquid nitrogen that will be used for shield refrigerating at 77 K and at the first stage of cooling down three accelerator rings with the total length of about 1 km and the "cold" mass of 290 tons. We demonstrate the location, basic parameters and design of major components of the nitrogen cryogenic system and discuss their phased commissioning.