New Hampshire Code of Administrative Rules
He - Department of Health and Human Services
Subtitle He-P - Former Division of Public Health Services
Chapter He-P 4000 - NEW HAMPSHIRE RULES FOR THE CONTROL OF RADIATION
Part He-P 4001 - SCOPE, EXEMPTIONS, AND GENERAL PROVISIONS
Section He-P 4001.09 - Units of Exposure and Dose
Current through Register No. 40, October 3, 2024
(a) As used in these rules, the unit of exposure shall be the coulomb per kilogram (C/kg) of air.
(b) One roentgen shall be equal to 2.58 ×10-4 coulomb per kilogram of air.
(c) As used in these rules, the units of dose shall be:
(d) As used in these rules, the quality factors for converting absorbed dose to dose equivalent shall be as in Table 4001.1:
Table 4001.1 Quality Factors and Absorbed Dose Equivalencies
|
Type of Radiation |
Quality Factor (Q) |
Absorbed Dose Equal to a Unit Dose Equivalent |
|
X, gamma, or beta radiation and high speed electrons |
1 |
1 |
|
Alpha particles, multiple-charged particles, fission fragments and heavy particles of unknown charge |
20 |
0.05 |
|
Neutrons of unknown energy |
10 |
0.1 |
|
High-energy protons |
10 |
0.1 |
(e) If it is more convenient to measure the neutron fluence rate than to determine the neutron dose equivalent rate in sievert per hour or rem per hour, as provided in He-P 4001.09(f), 0.01 Sv (1 rem) of neutron radiation of unknown energies may, for purposes of these rules, be assumed to result from a total fluence of 25 million neutrons per square centimeter incident upon the body.
(f) If sufficient information exists to estimate the approximate energy distribution of the neutrons, the licensee or registrant may use the fluence rate per unit dose equivalent or the appropriate Q value from Table 4001.2 to convert a measured tissue dose in gray or rad to dose equivalent in sievert or rem.
(g) As used in these rules, the mean quality factors, Q, and fluence per unit dose equivalent for monoenergetic neutrons shall be as shown in Table 4001.2 below:
Table 4001.2 Mean Quality Factors, Q, and Fluence Per Unit Dose Equivalent for Monoenergetic Neutrons
|
Neutron Energy (MeV) |
Quality Factor (Q) |
Fluence per Unit Dose Equivalent |
Fluence per Unit Dose Equivalent |
|
(thermal) 2.5 × 10-8 |
2 |
980 × 106 |
980 × 108 |
|
1 × 10-7 |
2 |
980 × 106 |
980 × 108 |
|
1 × 10-6 |
2 |
810 × 106 |
810 × 108 |
|
1 × 10-5 |
2 |
810 × 106 |
810 × 108 |
|
1 × 10-4 |
2 |
840 × 106 |
840 × 108 |
|
1 × 10-3 |
2 |
980 × 106 |
980 × 108 |
|
1 × 10-2 |
2.5 |
1010 × 106 |
1010 × 108 |
|
1 × 10-1 |
7.5 |
170 × 106 |
170 × 108 |
|
5 × 10-1 |
11 |
39 × 106 |
39 × 108 |
|
1 |
11 |
27 × 106 |
27 × 108 |
|
2.5 |
9 |
29 × 106 |
29 × 108 |
|
5 |
8 |
23 × 106 |
23 × 108 |
|
7 |
7 |
24 × 106 |
24 × 108 |
|
10 |
6.5 |
24 × 106 |
24 × 108 |
|
14 |
7.5 |
17 × 106 |
17 × 108 |
|
20 |
8 |
16 × 106 |
16 × 108 |
|
40 |
7 |
14 × 106 |
14 × 108 |
|
60 |
5.5 |
16 × 106 |
16 × 108 |
|
100 |
4 |
20 × 106 |
20 × 108 |
|
200 |
3.5 |
19 × 106 |
19 × 108 |
|
300 |
3.5 |
16 × 106 |
16 × 108 |
|
400 |
3.5 |
14 × 106 |
14 × 108 |
(h) Value of quality factor (Q) in Table 4001.2 shall be the point where the dose equivalent is maximum in a 30-centimeter diameter cylinder tissue-equivalent phantom.
(i) Fluence per unit dose equivalent in Table 4001.2 shall be monoenergetic neutrons incident normally on a 30-centimeter diameter cylinder tissue-equivalent phantom.
#5903, eff 2-1-95; ss by #6827, eff 8-6-98 (renumbered by #8488, from He-P 4001.08); ss by #8692, INTERIM, eff 7-27-06, EXPIRES: 2-2-07; ss by #8808, eff 1-24-07
