Table 3.

Summary of probability distributions of radiation effectiveness factors (REFs) for neutrons and alpha particles in IRER^a

Neutrons and solid cancer^b		95% credibility interval of REF_H^c
Energy	Exposure	2.5^th percentile	50^th percentile	97.5^th percentile
0.1–2 MeV	Acute	2.0	7.7	30
	Chronic	2.4	10	47
10–100 keV; 2–20 MeV	Acute	1.2	3.8	18
	Chronic	1.4	4.7	28
<10keV; >20 MeV	Acute	1.1	1.9	11
	Chronic	1.1	2.4	16

Neutrons and leukemia^b		95% credibility interval of REF_L^d
Energy	Exposure	2.5^th percentile	50^th percemile	97.5^th percentile

0.1–2 MeV	Acute	2.0	11	60
	Chronic	2.5	14	91
10–100 keV; 2–20 MeV	Acute	1.3	5.6	36
	Chronic	1.5	7.1	55
<10 keV; >20 MeV	Acute	1.1	2.8	22
	Chronic	12	3.4	34

Alpha particles^e		95% credibility interval of REF_L^d
Cancer type	Exposure	2.5^th perrentile	50^th percentib	97.5t^h percentile

Solid cancers	All	3.4	18	100
Leukemia	All	1.0	4.1	42

Adapted from Table 14 of Kocher et aL (2005). Many probability distributions are not described by commonly used continuous distributions (e.g., lognormal).

Probability distributions are described in Table 5 of Kocher et al. (2005): distributions under conditions of chronic exposure include enhancement factor to represent inverse dose-rate effect.

REF_H is REF at high doses and high dose rates of reference high-energy (>250 keV) photons.

REF_L is REF at low doses and low dose rates of reference high-energy (>25Q keV) photons.

Probability distributions are described in Table 7 of Kocher et al. (2005) and apply to alpha particles of any energy produced in radioactive decay; all distributions include enhancement factor to represent inverse dose-rate effect.