South Carolina Code of Regulations
Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL
Subchapter 61-63 - Radioactive Materials (Title A)
Part I - GENERAL PROVISIONS
Section 61-63.I.RHB 1.4 - Test and Surveys

Universal Citation: SC Code Regs 61-63.I.RHB 1.4

Current through Register Vol. 48, No. 9, September 27, 2024

1.4.1 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.

1.4.1.1 One becquerel = 1 disintegration per second (s-1).

1.4.1.2 One curie = 3.7 X 1010 disintegrations per second = 3.7 X 1010 becquerels =2.22 X 1012 disintegrations per minute. Commonly used submultiples of the curie are the millicurie (mCi) and the microcurie (uCi). One mCi = .001 curie (Ci) = 3.7 X 107 dps or 2.22 X 109 dpm. One uCi = .000001 Ci = 2.22 X 106 dpm.

1.4.2 For purposes of these regulations, it may be assumed that the daughter activity concentrations in the following table are equivalent to an air concentration of 10-7 microcuries of Radon 222 per milliliter of air in equilibrium with the daughters RaA, RaB, RaC, and RaC [FN1]

Alpha-emitting daughter activity collected per millimeter of air

Maximum time between collection and measurement (hours) [FN*]

Microcuries/ml.

Total alpha disintegrations per minute per ml.

0.5

7.2 x 10-8

0.16

1

4.5 x 10-8

0.10

2

1.3 x 10-8

0.029

3

0.3 x 10-8

0.0067

[FN*] The duration of sample collection and the duration of measurement should be sufficiently short compared to the time between collection and measurement, as not to have a statistically significant effect upon the results.

[FN1] Note: The unit 'Ci' is the currently used abbreviation for 'curie' replacing the older unit 'c'. Where the unit 'c' occurs in the text or tables of these regulations, it is to be interpreted to mean 'Ci', likewise uc = uCi and mc = mCi.

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