To check the barred Tee (Strips/bars are welded at the top of portion of Tee to avoid slipping of pig while launching) internal (whether any rod is loose/broken)in 14" size of 20mm WT which is the best RT technique can be used? Single wall single image or double wall single image? What type of film to used (slow or fast) for the above application. Our source is Ir192 with 20 curie strength. RT will be taken with line full of oil.Kodak AA400 is o.k or suggest for good one.