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The phase locking of the QWRs by dynamic phase control method in the superconducting linac at IUAC is done in a faster time scale. The slow frequency drifts (few hundreds of ms) are corrected using a niobium bellows tuner attached at the open end of the cavity. Initially, the tuners in the cavities were operated using helium gas. This system had the limitation of non-linearity, hysteresis and slow response due to which the cavities could not be phase locked at higher fields. To address this, piezo based tuning system was implemented in the cavities of the 2nd and 3rd linac modules. But due to space constraints, the same could not be used in the 1st linac module and the buncher modules. For them, the helium gas based system was continued, albeit with suitable modifications. The old flow control valves which operated with DC voltages were replaced with valves operating in pulsed mode and controlled by varying the duty cycle of the input pulses. The above mentioned limitations were overcome by using this PWM based technique and this enabled phase locking at higher gradients. This paper presents our operational experience with all the different tuning systems and their comparison., Proceedings of the 20th International Conference on RF Superconductivity, SRF2021, East Lansing, MI, USA

High Current Injector (HCI) is an upcoming heavy ion accelerator facility at Inter-University Accelerator Centre (IUAC), New Delhi, INDIA and it will serve as an alternate injector to the existing Superconducting Linear Accelerator. HCI is designed to achieve the maximum energy gain of 1.8 MeV/u for the ions, including the Noble gasses and metallic ions, having A/q less than equal to 6. It consists of an 18 GHz High Temperature Superconducting Electron Cyclotron Resonance Ion Source, Multi-harmonic Buncher, Radio Frequency Quadrupole (RFQ), Spiral Buncher and six interdigital H-mode Drift Tube Linac (IH-DTL) cavities operating at 97 MHz resonant frequency. The RFQ accelerates the ions from 8 keV/u to 180 keV/u energy and the six DTL cavities are used to achieve the maximum energy gain of 1.8 MeV/u. Recently, the bunched beam of N⁵⁺ was successfully accelerated through RFQ and six IH-DTL cavities and we achieved the designed energy, which is an important milestone of this project. These results validate the design parameters of all RF cavities, accelerating to achieve the designed energy goal of 1.8 MeV/u. Here, present status and future plans of the project shall be presented., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand