Radiography of Large Solid Propellant Rocket Motors

This paper presents experimental data on the radiography of propellant and information on the inspection of the Polaris motor. The X-ray energy range investigated was from 2 to 26 Mev. The half value layer thicknesses for propellant were determined to be 2.85, 6.5, and 7.7 in. for X-ray energies of 2000 kvp, 10 Mev, and 22 Mev, respectively. Experimental data with a penetrameter sensitivity of 0.25 per cent were obtained through 40 in. of propellant, using a 22-Mev betatron. The radiographic techniques with a 22-Mev betatron have been applied to the inspection of the Polaris motor. The use of a linear accelerator in X-ray inspection of propellant is feasible. This machine with its characteristically high output should materially reduce inspection time and costs.