Section 120.533 - Calibration of Survey Instruments(A) A licensee shall ensure that the survey instruments used to show compliance with 105 CMR 120.200 and 120.500 have been calibrated before first use, annually, and following repair.(B) To satisfy the requirements of 105 CMR 120.533(A), the licensee shall: (1) Calibrate all required scale readings up to ten millisieverts (1000 mrem) per hour with a radiation source;(2) Have each radiation survey instrument calibrated:(a) At energies appropriate for use and at intervals not to exceed 12 months or after instrument servicing, except for battery changes;(b) For linear scale instruments, at two points located approximately A and % of fullscale on each scale; for logarithmic scale instruments, at mid-range of each decade, and at two points of at least one decade; and for digital instruments, at three points between 0.02 and ten millisieverts (two and 1000 mrem) per hour; and(c) For dose rate instruments, so that an accuracy within plus or minus 20% of the true radiation dose rate can be demonstrated at each point checked.(3) Conspicuously note on the instrument the date of calibration.(C) The licensee shall not use survey instruments if the difference between the indicated exposure rate and the calculated exposure rate is greater than 20%.(D) The licensee shall retain a record of each survey instrument calibration in accordance with 105 CMR 120.590(G).Amended by Mass Register Issue 1480, eff. 10/14/2022.