MISTRAS CAME TO OCEAN CORP TO GIVE US A RT DEMONSTRATION.

 Here is a calculated 2 MR/HR boundary for compliance with radiation safety therefore no one get overexposed with radiation
The roentgen (R, also röntgen) is an obsolete unit of measurement for the kerma of X-rays and gamma rays up to 3 MeV. It is named after the German physicist Wilhelm Röntgen, the man who discovered X-rays. Originating in 1908, this unit has been redefined and renamed over the years.^[1] It was last defined by the US National Institute of Standards and Technology (NIST) in 1998 as 2.58×10⁻⁴ C/kg, (1 C/kg = 3876 R,) with a recommendation that the definition be given in every document where the roentgen is used.^[2] One roentgen of air kerma deposits 0.00877 gray (0.877 rad) of absorbed dose in dry air, or 0.0096 gray (0.96 rad) in soft tissue.^[3] One roentgen (air kerma) of X-rays may deposit anywhere from 0.01 to more than 0.04 gray (1 to 4 rad) in bone depending on the beam energy.^[4] This tissue-dependent conversion from roentgen to rad is called the F-factor in radiotherapy contexts. The conversion depends on the ionizing energy of a standard medium, which is ambiguous in the latest NIST definition. Even where the standard medium is fully defined, the ionizing energy of the calibration and target mediums are often not precisely known.

Radiographic Testing (RT), or industrial radiography, is a nondestructive testing (NDT) method of inspecting materials for hidden flaws by using the ability of short wavelength electromagnetic radiation (high energy photons) to penetrate various materials.
 
The beam of radiation must be directed to the middle of the section under examination and must be normal to the material surface at that point, except in special techniques where known defects are best revealed by a different alignment of the beam. The length of weld under examination for each exposure shall be such that the thickness of the material at the diagnostic extremities, measured in the direction of the incident beam, does not exceed the actual thickness at that point by more than 6%. The specimen to be inspected is placed between the source of radiation and the detecting device, usually the film in a light tight holder or cassette, and the radiation is allowed to penetrate the part for the required length of time to be adequately recorded.
The result is a two-dimensional projection of the part onto the film, producing a latent image of varying densities according to the amount of radiation reaching each area. It is known as a radiograph, as distinct from a photograph produced by light. Because film is cumulative in its response (the exposure increasing as it absorbs more radiation), relatively weak radiation can be detected by prolonging the exposure until the film can record an image that will be visible after development. The radiograph is examined as a negative, without printing as a positive as in photography. This is because, in printing, some of the detail is always lost and no useful purpose is served.
Before commencing a radiographic examination, it is always advisable to examine the component with one's own eyes, to eliminate any possible external defects. If the surface of a weld is too irregular, it may be desirable to grind it to obtain a smooth finish, but this is likely to be limited to those cases in which the surface irregularities (which will be visible on the radiograph) may make detecting internal defects difficult.
After this visual examination, the operator will have a clear idea of the possibilities of access to the two faces of the weld, which is important both for the setting up of the equipment and for the choice of the most appropriate technique.
Defects such as delaminations and planar cracks are difficult to detect using radiography, which is why ultrasonics is the preferred method for detecting this type of discontinuity.