Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

■ Comparison of Penetrameter Design
The hole type of penetrameter (ASTM, ASME) is, in a sense, a "go no-go"
gauge; that is, it indicates whether or not a specified quality level has been
attained but, in most cases, does not indicate whether the requirements have
been exceeded, or by how much. The DIN penetrameter on the other hand is
a series of seven penetrameters in a single unit. As such, it has the
advantage that the radiographic quality level achieved can often be read
directly from the processed radiograph. On the other hand, the hole
penetrameter can be made of any desired material but the wire penetrameter
is made from only a few materials. Therefore, using the hole penetrameter, a
quality level of 2-2T may be specified for the radiography of, for example,
commercially pure aluminum and 2024 aluminum alloy, even though these
have appreciably different compositions and radiation absorptions. The
penetrameter would, in each case, be made of the appropriate material. The
wire penetrameters, however, are available in aluminum but not in 2024 alloy.
To achieve the same quality of radiographic inspection of equal thicknesses
of these two materials, it would be necessary to specify different wire
diameters--that for 2024 alloy would probably have to be determined by
experiment.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980