[en] Plasma heating to fusion temperatures and its diagnosis in ITER machine is to be achieved using deuterium beams, 1 MeV 40 A, and hydrogen beams, 0.1 MeV, 60A, respectively. Such beam currents are to be achieved from ion sources having large extraction areas, ∼ 2m² , and using set of multi-aperture multi-segment grid system which electrostatically provide the desired beam acceleration and control the beam optics as well. Development of beams of this magnitude is a key R and D issue. India, in collaboration with ITER, has undertaken the mandate to develop and demonstrate the performance of this ion source. It forms the basis of one of its primary R and D objective, where the performance of the ITER ion source for the Diagnostic Neutral Beam (DNB), shall be established, in the Indian Test Facility (IN-TF) in IPR