[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: 10CFR20.1005] [Page 327] TITLE 10--ENERGY CHAPTER I--NUCLEAR REGULATORY COMMISSION PART 20--STANDARDS FOR PROTECTION AGAINST RADIATION--Table of Contents Subpart A--General Provisions Sec. 20.1005 Units of radioactivity. For the purposes of this part, activity is expressed in the special unit of curies (Ci) or in the SI unit of becquerels (Bq), or their multiples, or disintegrations (transformations) per unit of time. (a) One becquerel = 1 disintegration per second (s-1). (b) One curie = 3.7x10 \10\ disintegrations per second = 3.7x10 \10\ becquerels = 2.22x10 \12\ disintegrations per minute. [56 FR 23391, May 21, 1991; 56 FR 61352, Dec. 3, 1991]