At the Inter University Accelerator Centre, Delhi, the High Current Injector Programme mainly consisting of an 18 GHz High Temperature Superconducting ECR Ion Source on a 100 keV high voltage platform followed by radiofrequency quadrupole and drift tube linear accelerators will serve as an alternate injector to the existing Superconducting Linear accelerator. Studies related to the longitudinal emittance measurements before injection into the radiofrequency accelerators are important to understand the longitudinal optics through the system. Earlier studies  have shown that plasma potentials in an ECR ion source inherently produces energy spread in the extracted ion beams, which can adversely affect the transmission through the downstream radiofrequency quadrupole accelerator. In the present study, longitudinal emittance measurements will be carried out for various ion beams using a multi-harmonic buncher and a fast Faraday cup. The influence of the plasma potential, measured in-situ, on the longitudinal emittances will be presented.
 G. Rodrigues, R. Baskaran, S. Kukrety, Y. Mathur, Sarvesh Kumar, A. Mandal, D. Kanjilal and A. Roy, Rev.Sci.Instrum. 83,033301 (2012).