The Energy Calibration System for the CUORE Bolometric Double Beta Decay Experiment

CUORE, the Cryogenic Underground Observatory for Rare Events, employs an array of 988 TeO$_{2}$ bolometers to search for neutrinoless double beta decay ($\beta\beta0\nu$) in $^{130}$Te. The signature for $\beta\beta0\nu$ is a peak at the expected Q-value of 2530~keV in the summed energy spectrum of all detectors. In CUORE, bolometers are operated as perfect calorimeters and therefore a precise and reliable energy calibration is crucial for the success of the experiment. An innovative calibration system is being developed to provide energy calibration of all the detectors in the CUORE array. The project is particularly complex due to its integration in a unique low-temperature cryostat (detectors operate at 10~mK) and to the strict ultra-low background requirements of CUORE. We present the design, challenges and expected performances of this low-temperature calibration system.