[Code of Federal Regulations] [Title 10, Volume 1] [Revised as of January 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 10CFR35.61] [Page 577] TITLE 10--ENERGY CHAPTER I--NUCLEAR REGULATORY COMMISSION PART 35--MEDICAL USE OF BYPRODUCT MATERIAL--Table of Contents Subpart C--General Technical Requirements Sec. 35.61 Calibration of survey instruments. (a) A licensee shall calibrate the survey instruments used to show compliance with this part and 10 CFR Part 20 before first use, annually, and following a repair that affects the calibration. A licensee shall-- (1) Calibrate all scales with readings up to 10 mSv (1000 mrem) per hour with a radiation source; (2) Calibrate two separated readings on each scale or decade that will be used to show compliance; and (3) Conspicuously note on the instrument the date of calibration. (b) A licensee may not use survey instruments if the difference between the indicated exposure rate and the calculated exposure rate is more than 20 percent. (c) A licensee shall retain a record of each survey instrument calibration in accordance with Sec. 35.2061. [[Page 578]]