32 Ill. Adm. Code 351.1040
Radiation Survey Instruments
Section 351
Section 351.1040 Radiation
Survey Instruments
a) The licensee or registrant shall maintain sufficient
calibrated and operable radiation survey instruments at each field station to
make physical radiation surveys as required by this Part and by 32 Ill. Adm.
Code 340.510(a). Instrumentation shall be capable of measuring 0.001 mSv (0.1
mrem) per hour through at least 0.5 mSv (50 mrem) per hour. This range is
considered equivalent to 25.8 nC/kg (100 microR) per hour through at least
5.16 microC/kg (20 mR) per hour for the gamma radiation sources typically used
in well-logging.
b) Each radiation survey instrument shall be calibrated:
1) At intervals not to exceed 6 months and after each instrument
servicing (e.g., electronic repair);
2) At energies and radiation levels equivalent to those to be
encountered during use; and
3) So that accuracy within plus or minus 20 percent of the true
radiation level can be demonstrated on each scale.
c) Calibration records shall be maintained for a period of 2
years for inspection by the Agency.