Table 1
QUALITY FACTORS AND ABSORBED DOSE EQUIVALENTS
Type of radiation | Quality factor (Q) | Absorbed dose equal to a unit dose equivalenta |
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 |
a Absorbed dose in rad equal to 1 rem or the absorbed dose in gray equal to 1 Sv.
Table 2
MEAN QUALITY FACTORS, Q, AND FLUENCE PER UNIT DOSE EQUIVALENT FOR MONOENERGETIC NEUTRONS
Neutron energy (MeV) | Quality factoraQ | Fluence per unit dose equivalentb (neutrons/cm2/rem) | Fluence per unit dose equivalentb (neutrons/cm2/Sv) |
2.5 × 10-8 (thermal) | 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 × 188 |
2.5 | 9 | 29 ×106 | 29 ×108 |
5 | 8 | 23 × 106 | 23 ×106 |
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 |
1 × 102 | 4 | 20 ×106 | 20 ×108 |
2 ×102 | 3.5 | 19 ×106 | 19 ×108 |
3 ×102 | 3.5 | 16 ×106 | 16 × 108 |
4 ×102 | 3.5 | 14 x 106 | 14 × 108 |
a Value of quality factor (Q) at the point where the dose equivalent is maximum in a 30-cm diameter cylinder tissue-equivalent phantom.
b Monoenergetic neutrons incident normally on a 30-cm diameter cylinder tissue-equivalent phantom.
175 (grams contained U-235) | + | 50 (grams U-233) | + | 50 (grams Pu) | = 1 |
350 | 200 | 200 |
175 (grams contained U-235)/350 + 50 (grams U-233)/200 +50 (grams Pu)/200 = 1
ORGAN DOSE WEIGHTING FACTORS
Organ or tissue | WT |
Gonads | 0.25 |
Breast | 0.15 |
Red bone marrow | 0.12 |
Lung | 0.12 |
Thyroid | 0.03 |
Bone surfaces | 0.03 |
Remainder | 0.30a |
Whole body | 1.00b |
a 0.30 results from 0.06 for each of five "remainder" organs, excluding the skin and the lens of the eye, that receive the highest doses.
b For purposes of weighting the external whole body dose, for adding it to the internal dose, a single weighting factor, W T =1.0, has been specified. The use of other weighting factors for external exposure will be approved on a case-by-case basis until such time as specific guidance is issued.
Footnotes
a Absorbed dose in rad equal to 1 rem or the absorbed dose in gray equal to 1 Sv.
b Monoenergetic neutrons incident normally on a 30-cm diameter cylinder tissue-equivalent phantom.
1 The documents referenced in this Part are available for review and copying at the New York State Department of Labor, State Office Campus, Building 12, Room 509, Albany, NY or the New York State Department of State, 162 Washington Avenue, Albany, NY.
2 At very high doses received at high dose rates, units of absorbed dose, gray and rad, are appropriate, rather than units of dose equivalent, sievert and rem.
N.Y. Comp. Codes R. & Regs. Tit. 12 § 38.3