Contreras-Martinez, C. Giaccone, B. Gonin, I.V. Khabiboulline, T.N. Melnychuk, O.S. Pischalnikov, Y.M. Posen, S. Pronitchev, O.V. Yun, J.C. JACoW Publishing Geneva, Switzerland 2673-5504 978-3-95450-234-9 10.18429/JACoW-SRF2023-WEPWB133 English 907-910 cavity photon SRF experiment ECR Contribution to a conference proceedings 2023 2023-09 https://doi.org/10.18429/JACoW-SRF2023-WEPWB133 https://jacow.org/srf2023/papers/wepwb133.pdf At FNAL two 2.6 GHz SRF cavities are being used to search for dark photons, the experiment can be conducted at 2 K or in a dilution refrigerator. Precise frequency tuning is required for these two cavities so they can be matched in frequency. A cooling capacity constraint on the dilution refrigerator only allows piezo actuators to be part of the design of the 2.6 GHz cavity tuner. The tuner is equipped with three encapsulated piezo that deliver the long- and short-range frequency tuning. Modifications were implemented on the first tuner design due to the low forces on the piezos due to the cavity. Three brass rods with Belleville washers were added to the design to increase the overall force on the piezos. The results at 2 K of testing this tuner with and without the modification will be presented.