The Divertor Tokamak Test (DTT) project (https://www.dtt-project.it/) was developed as a strategic initiative to investigate innovative solutions for the divertor, a key component responsible for handling power exhaust. To ensure its relevance to ITER and DEMO, DTT must be capable of sustaining sufficiently long plasma pulses, which requires the adoption of a superconducting magnetic system. Consequently, DTT relies on a dedicated cryogenic system to provide thermal control for the magnets and associated components.
At the core of the DTT device are Low Temperature Superconducting (LTS) magnets designed to generate very high magnetic fields with limited electrical power consumption. Their reliable operation requires cryogenic cooling temperatures of approximately 4.5 K. To mitigate radiative heat loads from the surrounding environment, the magnet system is protected with dedicated thermal shields actively cooled by pressurized helium at about 80 K. An intermediate temperature level of around 50 K is required to cool the high-temperature superconducting (HTS) current leads, which provide the electrical connection between the magnets and their power supplies. In addition, the cryogenic system shall also provide cooling to the DTT cryogenic vacuum pumping system, which consists of ten cryopump panels operating at approximately 4.5 K and cryopump baffles maintained at around 80 K.
Within this framework, the DTT cryogenic system has been specifically designed to operate over multiple temperature levels while accommodating highly variable heat loads. These loads strongly depend on the operational state of the machine and are characterized by significant transients and pronounced thermal peaks during experimental campaigns and plasma operation. Accordingly, the cryogenic plant must ensure a high degree of flexibility, operational reliability, and efficient regulation of the cooling power under both steady?state and transient conditions.
This work presents an updated overview of the main components of the DTT cryogenic system, including design constraints, utilities, and interfaces, together with a detailed analysis of the cooling requirements during the different operational phases of the machine.

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