From Nymik- COSPAR

GCR Deceleration Potential

200

400

600

800

1000

1200

1400

1600

1800

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

Year

F, M

V

+ + + +- - -

1/1/1950 1/1/1960 1/1/1970 1/1/1980 1/1/1990 1/1/2000 1/1/2010 1/1/2020

F(>

30

MeV

), P

roto

ns/

cm2

108

109

1010F>108 solar protonevents only

SPE estimates from Artic Ice-Core Nitrate Samples

Large SPE’s

GCR and SPE Dose: Materials & Tissue GCR higher energy >> secondary radiation

Shielding Depth, g/cm2

0 5 10 15 20 25 30 35

Dos

e E

quiv

alen

t, cS

v/yr

1

10

100

1000

10000

GCR HydrogenGCR PolyethyleneGCR GraphiteGCR AluminumGCR RegolithSPE GraphiteSPE Regolith

Shielding Depth, g/cm2

0 5 10 15 20 25 30 35

Dose

Eq

uiv

ale

nt, c

Sv/

yr

1

10

100

1000

GCR HydrogenGCR PolyethyleneGCR GraphiteGCR AluminumGCR RegolithSPE GraphiteSPE RegolithSPE Hydrogen

No Tissue Shielding With Tissue Shielding

Risk and Uncertainties increase with Linear Energy Transfer (LET)

LET, keV/m

1 10 100 1000

RE

ID(%

) 0

1

2

3

4

5

6

7

8

Fold uncertainty

Dose = 0.01 Gy

TEPC Data on NASA-MIR 7 (1/21/1998 to 5/28/1998)

y (~LET), keV/m

0.1 1 10 100 1000

F(>

y),

(day

cm

2 )-1

0.01

0.1

1

10

100

1000

10000

GCRTrappedTotal

Dose = Flux x LETBiological Dose H = Dose X Q(L)REID = Risk of exposure induced death = H x R0(sex,age)

95% CL of Risk Model

Accuracy of Space Radiation Transport Models

Model vs. Phantom Expt. (STS and ISS)

ISS Increment-2results

Role of Dose-Rate and Shielding Shielding mitigates most SPE events

High-energy component (>100 MeV) often poorly known Proton biological damage is dependent on dose-rate

Effects increase above ~5 rad/hr

EVA Today (Y/N?)IVA (time to storm shelter)

Long-Term ForecastingClimax Neutron Monitor and Deceleration Potential (F)

1900

2400

2900

3400

3900

4400

1953 1963 1973 1983 1993 2003 2013

Time

Clim

ax

Co

sm

ic R

ay

Mo

nth

ly M

ea

ns

400

900

1400

1900

2400

2900

F,

MV

Measured ClimaxNMEstimated Cli(DR75%)PHI(T)3-month Ave PHI(T)

Phantom Torso TEPC Trapped + GCR Differential FluxJune 25 - July 3, 2001

Lineal Energy (Tissue, keV/m)

10-1 100 101 102 103 104

Diff

eren

tial F

lux,

Num

ber/

cm2 s

r da

y ke

V/

m

10-5

10-4

10-3

10-2

10-1

100

101

102

103

104

105

NASA-MIR 7 (1/21/1998 to 5/28/1998)

y, keV/m

0.1 1 10 100 1000

F(>

y), (

day

cm2 )-1

0.01

0.1

1

10

100

1000

10000

GCRTrappedTotal

1.E-05

1.E-03

1.E-01

1.E+01

1.E+03

1.E+05

1.E+07

0.01 0.1 1 10 100 1000

0" (x100)

5" (x10)

7" (x1)

9" (x0.1)

1.E-05

1.E-03

1.E-01

1.E+01

1.E+03

1.E+05

1.E+07

0.01 0.1 1 10 100 1000

0" (x100)

5" (x10)

7" (x1)

9" (x0.1)

LET vs TEPC

TEPC model Vs TEPC (no TF)