U.S. Nuclear Regulatory Commission
Question 96: (a) The roentgen (R) is not defined or used
in revised Part 20; however, many survey instruments and
computer records show dose rates in terms of "mR/h" or
"R/h." Will these survey instrument face pieces and
computer forms have to be changed when revised Part 20 is
implemented? (b) Most radiation instrumentation is
currently calibrated in units of roentgens rather than
rads. A roentgen of x- or gamma-radiation in the energy
range of 0.1 - 3 MeV produces 0.96 rad in tissue. Will
these instruments need to be recalibrated to account for
Answer: (a) No. The survey instruments will not need to
be changed. See Question 428 for additional information
concerning the use of the unit "roentgen" and its subunits.
(b) No. It may be assumed that one roentgen equals one rem
or a more accurate conversion factor may be used.
(References: 10 CFR 20.1003, 10 CFR 20.2101).