APPENDIX G: Neutron Dose Data

1. Conversion factors and effective quality factors for neutrons, as provided by the Nuclear Regulatory Commission in "10 CFR Part 20":

Neutron Energy (Mev)	Fluence per unit dose equivalent(a) (neutrons/cm2 per rem)	Quality Factor(b) (Q)
2.5 x 10 -8 (thermal)	980 x 10 6	2
1 x 10 -7	980 x 10 6	2
1 x 10 -6	810 x 10 6	2
1 x 10 -5	810 x 10 6	2
1 x 10 -4	840 x 10 6	2
1 x 10 -3	980 x 10 6	2
1 x 10 -2	1010 x 10 6	2.5
0.1	170 x 10 6	7.5
0.5	39 x 10 6	11
1	27 x 10 6	11
2.5	29 x 10 6	9
5	23 x 10 6	8
7	24 x 10 6	7
10	24 x 10 6	6.5
14	17 x 10 6	7.5
20	16 x 10 6	8
40	14 x 10 6	7
60	16 x 10 6	5.5
1 x 10 2	20 x 10 6	4
2 x 10 2	19 x 10 6	3.5
3 x 10 2	16 x 10 6	3.5
4 x 10 2	14 x 10 6	3.5

• Monoenergetic neutrons incident normally on a 30-cm diameter cylinder tissue-equivalent phantom.
• Value of quality factor (Q) at the point where the dose equivalent is maximum in a 30-cm diameter cylinder tissue-equivalent phantom.

2. The Nuclear Regulatory Commission states that, when the energy distribution is unknown, 25 x 106 neutrons/cm2 incident upon the body shall be assumed to be equivalent to one rem, and the Quality Factor is assumed to be 10.

3. Averaged neutron dose per unit flux for several neutron sources. Data provided by M. Awschalom.

Source	mrem/neutron/cm2
Pu-239 - Be	3.5 x 10 -5
U-235 (fission)	2.8 x 10 -5
1/E Spectrum (0-24 Mev)	7.9 x 10 -6

4. Dose rate from 1 Curie 239Pu-Be source: 2.2 mRem/hr @ 100 cm based on typical emission rate of 2 x 106 neutrons/sec.