extrapolated range

in radiochemistry
The distance from a radiation source, calculated by extrapolation to zero of the flux density, of the tangent to the flux density versus distance curve, taken at the point where the flux density has decreased to one half of its initial value.
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1541 [Terms] [Paper]