In the frame of the CARE project activities supported by EU, IPN Orsay participates to the development of a fast cold tuning system for SRF cavities operating at a temperature T=2 K. The study is aimed at full characterization of piezoelectric actuators at low temperature. A new experimental facility was developed for testing various prototypes piezoelectric actuators and successfully operated for T in the range 1.8 K-300 K. Different parameters were investigated as function of T: piezoelectric actuator displacement vs. applied voltage V, capacitance vs. T, dielectric and thermal properties vs. T and finally heating ∆Τ due to dielectric losses vs. modulating voltage Vmod and frequency f. We observed a decrease of the Full Range Displacement (FRD or ∆X) of the actuators from ~40µm @ 300K down to 1.8µm-3µm @ 1.8K, depending on both material and fabrication process of the piezostacks. Besides, both material and fabrication process have a strong influence on the shape of the characteristics ∆X vs. T dependence. Moreover, the variations of loss tangent (tg(δ)) with T show a maximum at T in the range 30 K-120 K. Finally a dedicated facility located at Orléans (CERI) for radiation hardness tests of actuators with fast neutrons at T=4.2 K was developed and the first beam tests results are summarized. AbstractIn the frame of the CARE project activities supported by EU, IPN Orsay participates to the development of a fast cold tuning system for SRF cavities operating at a temperature T=2 K. The study is aimed at full characterization of piezoelectric actuators at low temperature. A new experimental facility was developed for testing various prototypes piezoelectric actuators and successfully operated for T in the range 1.8 K-300 K. Different parameters were investigated as function of T: piezoelectric actuator displacement vs. applied voltage V, capacitance vs. T, dielectric and thermal properties vs. T and finally heating ∆Τ due to dielectric losses vs. modulating voltage V mod and frequency f. We observed a decrease of the Full Range Displacement (FRD or ∆X) of the actuators from ~40µm @ 300K down to 1.8µm-3µm @ 1.8K, depending on both material and fabrication process of the piezostacks. Besides, both material and fabrication process have a strong influence on the shape of the characteristics ∆X vs. T dependence. Moreover, the variations of loss tangent (tg(δ)) with T show a maximum at T in the range 30 K-120 K. Finally a dedicated facility located at Orléans (CERI) for radiation hardness tests of actuators with fast neutrons at T=4.2 K was developed and the first beam tests results are summarized.

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