[en] 6 MeV RF Electron linac-based X-ray source has been designed and developed at APPD, BARC for X-ray radiography applications. The linac operates in S-band (2856 MHz) with pulse width of 3.4 µs and rep.rate 40-100 Hz at peak electron current of 160 mA and RF peak power of 2.2 MW to generate 6 MeV electrons. X-ray conversion is achieved with the use of a water-cooled tantalum target. A 200 mm x 200 mm X-ray field area is generated at the end of a 450 mm long trapezoidal collimator. Qualification of the linac as an X-ray source for radiography was carried out at dose level of 1-2 Gy/min at various exposure rates. Wire-type (ASTM E 747) and hole type (ASTM E 1025) penetrameters have been used. Sensitivity of ∼1- 2% has been achieved. It is observed that linac can be used for industrial radiography of steel of thickness 100 – 200 mm with acceptable density requirement. Focal spot size of ∼1 mm has been estimated using MTF method. This paper discusses the performance of the 6 MeV linac for experiments needed for qualification and the results obtained. (author)