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 1.3 - Inspections

Current through Register Vol. 48, No. 6, June 28, 2024
1.3.1 "Dose" means the quantity of radiation
				absorbed, per unit of mass, by the body or by any portion of the body. When these
				regulations specify a dose during a period of time, the dose means the total
				quantity of radiation absorbed, per unit of mass, by the body or by any portion of
				the body during such period of time. Several different units of dose are in current
				use. Definitions of units as used in these regulations are set forth in the
				following paragraphs: 1.3.2 and 1.3.3.
1.3.2 The "rad" is a measure of the dose of any
				radiation to body tissues in terms of the energy absorbed per unit mass of the
				tissue. One rad is the dose corresponding to the absorption of 100 ergs per gram of
				tissue. (One millirad [mrad] = 0.001 rad.)
1.3.3 The "rem" is a measure of the dose of any
				radiation to body tissue in terms of its estimated biological effect relative to a
				dose of one roentgen (R) of x-rays. (One millirem [mrem] = 0.001 rem.) The relation
				of the rem to other dose units depends on the biological effect under consideration
				and upon the conditions of irradiation. For the purpose of these regulations, any of
				the following is considered to be equivalent to a dose of one rem:
1.3.3.1 A dose of 1 R due to × -or gamma
				radiation;
1.3.3.2 A dose of 1 rad due
				to ×-, gamma, or beta radiation;
1.3.3.3 A dose of 0.1 rad due to neutrons or high
				energy protons;
1.3.3.4 A dose of 0.05
				rad due to particles heavier than protons and with sufficient energy to reach the
				lens of the eye.
If it is more convenient to measure the neutron flux, or
				  equivalent, than to determine the neutron dose in rads, as provided in sub-paragraph
				  1.3.3.3 of this paragraph, one rem of neutron radiation may, for the purposes of
				  these regulations, be assumed to be equivalent to 14 million neutrons per square
				  centimeter incident upon the body; of, if there exists sufficient information to
				  estimate with reasonable accuracy the approximate distribution in energy of the
				  neutrons, the incident number of neutrons per square centimeter equivalent to one
				  rem may be estimated from the following table:
Neutron Energy (Mev)
NEUTRON FLUX DOSE EQUIVALENTS Number per square
								centimeter equivalent to a dose of 1 rem (Neutrons/cm 2)
Average Flux to deliver 100 millirem in 40 hrs.
								(Neutrons/cm 2/sec.)
Thermal
970 x 106
670
0.0001
720 x 106
500
0.005
820 x 106
570
0.02
400 x 106
280
0.1
120 x 106
80
0.5
43 x 106
30
1.0
26 x 106
18
2.5
29 x 106
20
5.0
26 x 106
18
7.5
24 x 106
17
10.0
24 x 106
17
10 to 30
14 x 106
10
1.3.3.5
				For determining the doses specified in RHA 3.2 a dose from ×- or gamma rays up
				to 3 mev may, for purposes of these regulations, be assumed to be equivalent to the
				exposure measured in air at or near body surfaces in the region of the highest dose
				rate by a properly calibrated appropriate instrument.