New results for Radiation Effects on the Human Health Obtained during the COST-724 Action F. Spurný a, Ts. Dachev b, a Nuclear Physics Institute, Czech.

New results for Radiation Effects on the Human Health Obtained during the COST-

724 Action

F. Spurnýa, Ts. Dachevb,

aNuclear Physics Institute, Czech Academy of Sciences, Prague, Na Truhlarce 39/64, 18086 Praha 8, Czech Republic, ([email protected];

Phone: +420 283841772)

bSolar-Terrestrial Influences Laboratory, Bulgarian Academy of Sciences (BAS), Acad. Georgi Bonchev St. Block 3, 1113 Sofia,

Bulgaria, ([email protected]; Tel.: + 359 28700307)

mailto:[email protected]




Spurny & DachevSpurny & Dachev COST-724 MCM meeting, Sofia, 22 May 2007COST-724 MCM meeting, Sofia, 22 May 2007 22

Table of content• Specificity of onboard spacecraft (Space)

radiation fields from the point of view of radiation risk

• Some of topics treated during COST 724: Investigation of earth radiation environment on

International Space Station on Foton M2 satellite and on Aircraft

Onboard spacecraft neutron contribution as estimated on the base of the comparison of results measured with MDU-Liulin equipment

Further analysis of long-term measurements onboard of Czech Airlines Aircraft


Specificity of onboard spacecraft (Space) radiation fields – compared to

Earth1. Exposure level much higher: ~ 1 mSv (Earth) to ~

several 100 mSv/year, nevertheless not too excessively; still low-dose region with very few data available on radiation risk

2. However - solar flares can appear – then up to

orders higher in open Space – accidental exposure

3. Much higher contribution of radiation with high linear energy transfer (LET) – also only few data available

4. For aircraft crew exposure – much more females concerned


Radiation Protection

Justification - final effect of the activity leading to an exposure would be positive

Optimization - to keep the exposure as low as achievableLimitation - not to exceed limits

Annual Limits (ICRP 60) Application Occupational Public

Effective dose 20 (50) mSv 1 mSv Equivalent dose in lens of the eye 150 mSv 15 mSv skin 500 mSv 50 mSv hands and feet 500 mSv -


Exposure limits in Space and/or on the Earth

Effective (equivalent) dose limits, Sv Russia-RSA NASA - USA Europe-ESA

Effective dose

Career limits

M F

1.0 1.0

M F 25y 0.7 0.4 35y 1.0 0.6 45y 1.5 0.9 55y 2.9 1.6

M F

1.0 1.0

BFO (5 cm depth)

Single acute 30 days 1 year

0.15 0.25 0.5

- 0.25 0.50

- 0.25 0.5

Ocular lens (0.3 cm depth)

Single acute 30 days 1 year Career limit

- 0.5 1.0 2.0

- 1.0 2.0 4.0

- 0.5 1.0 -

Skin (0.01 cm depth)

Single acute 30 days 1 year Career limit

- 1.5 3.0 6.0

- 1.5 3.0 6.0

- 1.5 3.0 -


Tasks to be treated

• To improve the conditions for safe prolongation of human space activities needs to diminish uncertainties related to the estimation of the risk, both biological factors as physical knowledge, both dosimetric as microdosimetric,

• For that, it is necessary: to accumulate data on actual level of exposure in

Space at different conditions and situations (flight altitude and other parameters, solar activity, shield thickness, galactic cosmic rays vs. solar component (SAA)), etc., not only quantitative but also qualitative data (microdosimetry)

to search for correlation between Space and close-to-Earth exposure levels


Activities WP2400/WG2 of COST 724

• Longer term monitoring and measurements onboard ISS and other space vehicles

• Studies during shorter space missions with more complex sets of instruments

• Long term monitoring as well as punctual measurements onboard aircraft (Czech Airlines)

• Search for correlation of these data sets considering actual situation characterising “Space Weather”

• Three examples follow


Simultaneous Investigation of Galactic Cosmic Rays on Aircrafts,

Foton M2 satellite and on International Space Station

0 10 20 30 40 50 60 70Geographic Latitude (deg)

0

2

4

6

8

10

Do

se (

uG

y/h

ou

r)

Foton M 2

Aircraft

ISS M DU#2

0

1

2

3

Flu

x (c

m^

-2 s

^-1

)

Foton M 2 (1-12 June 2005)

Aircraft (05.05-26.06.2005)

ISS M DU#2 (06.07-13:07.2001)

Average dose (uGy/h) in 10°-30° Lat. range Aircraft=0.66; Foton M2=1.34; ISS=1.94Av. Alt. (km): Aircraft=11; Foton=260; ISS=393


Distribution of Foton M2 earth radiation Distribution of Foton M2 earth radiation environment against the L valueenvironment against the L value

1 2 3 4 5 6L value

1E-1

1E+0

1E+1

1E+2

1E+3

Flu

x (c

m-2

.s-1

)

1E-1

1E+0

1E+1

1E+2

1E+3

Dose

(uG

y/hour)

1E+0

D/F

(nG

y.cm

2/par

t)

Inner (proton) Belt

Outher (electron) Belt

High energy protons (300-100 MeV)

Low energy protons (100-30 Mev)

Protons

Electrons

Brem ssthralung?

GCR


7% increase of the doses on aircraft altitudes 7% increase of the doses on aircraft altitudes in 2005 are observed because of lower solar in 2005 are observed because of lower solar

activityactivity

0.1 1.0 10.0Deposited energy (M eV)

1E-6

1E-5

1E-4

1E-3

1E-2

1E-1

Flu

x (c

m^-

2 s^

-1)

Y(02) = pow(X ,-2.27725) * 0 .00179186Y(02) = pow (X ,-2 .27362) * 0 .00196797

2005 (245 spectra)

2002 (258 spectra)

Power fit 2002

Power fit 2005

Prague-N ew York; A ltitude =35000 feet

2005 Average dose=1.87 uG y/h

2002 Average dose =1.74 uG y/h

C alculated D ose increase in 2005=7.02%

-80 -60 -40 -20 0 20Longitude (degree)

40

50

60

70

Latit

ude

(deg

ree)

5 M ay - 25 June 2005 Prague - New York

6 M ay - 17 June 2002 Prague - New York

30000

32000

34000

36000

38000

Alti

tude

(fe

et)

1.0

1.5

2.0

2.5

Dos

e (u

Gy/

hour

)

3.0

4.0

5.0

6.0

7.0

CA

RI (

uSv/

hour

)

-80 -60 -40 -20 0 20Longitude (degree)

40

50

60

70

Latit

ude

(deg

ree)

5 M ay - 25 June 2005 New York - P rague

6 M ay - 17 June 2002 New York - P rague

30000

32000

34000

36000

38000

40000

Alti

tude

(fe

et)

1.0

1.5

2.0

2.5

Dos

e (u

Gy/

hour

)

3.0

4.0

5.0

6.0

7.0

CA

RI (

uSv/

hour

)

820 MV820 MV 594 MV594 MV


The doses and fluxes obtained with the Foton M2 satellite The doses and fluxes obtained with the Foton M2 satellite confirms the westward drift of the SAA anomaly with confirms the westward drift of the SAA anomaly with

about 0.28 degree per yearabout 0.28 degree per year

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180-60

-40

-20

0

20

40

60L

atit

ud

e (d

eg)

0.3

0.4

0.5

0.8

1.0

1.5

3.0

5.0

7.0

10.0

17.0

27.0

37.0

50.0

Flu

x (c

m^

-2 s

^-1

)

Models dataModels dataR3DR3D--B2 dataB2 data

R3DR3D--B2 flux distribution dataB2 flux distribution data

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180-60

-40

-20

0

20

40

60L

atit

ud

e (d

eg)

0.3

0.4

0.5

0.8

1.0

1.5

3.0

5.0

7.0

10.0

17.0

27.0

37.0

50.0

Flu

x (c

m^

-2 s

^-1

)

Models dataModels dataR3DR3D--B2 dataB2 data

R3DR3D--B2 flux distribution dataB2 flux distribution data


Onboard spacecraft neutron contribution as estimated on the base of the comparison of results measured

with MDU-Liulin equipment• Neutron contribution to the spacecraft crew exposure

could represent up to several tens % of the total value of the dose equivalent. The determination of this contribution represents rather complex and difficult task, both through experimental as theoretical estimation; up to now great differences in estimations

• An attempt to appreciate the neutron contribution onboard International Space Station and Foton capsule using the data measured by means of a Si-diode based energy deposition spectrometer, and on their comparison with on-Earth and onboard aircraft measured data


Spacecraft and aircraft flight conditions

• International Space Station – May 2001, inclination 51.6o, altitudes between 360 and 420 km; shield about 20 g.cm-2, total D(Si) ~ 6 mGy

• Foton M2 capsule – May 2005, inclination 62.6o, altitudes between 260 and 304 km; shield ~ 2 g.cm-2, total D(Si) ~ 0.6 mGy

• Aircraft – A310-300 – since 22/03/01, 12 two month’s runs, more than 1100 flights, mostly over the North Atlantic, about 5000 hours at flight altitude, total D(Si) ~ 9.3 mGy; > 40000 spectra


Comparison of energy deposition spectra - 3

Relative contribution (RC) to Edep

0.0001

0.001

0.01

0.1

1

0.01 0.1 1 10 100Edep, MeV

Ed

ep

*RC

(Ed

ep

)

aircraft

ISSGCR

ISSSAA


Spacecraft board interpretation procedure

1. GCR: Supposed that:• Edep bellow ~ 1 MeV – low LET component• Edep above ~ 1 MeV composed of: neutron component with similar spectra as onboard aircraft, and contribution of HECP of GCR Interpreted as:• Low LET component: D(Si)→D(tissue)→”H*(10)”;• Neutron component: as onboard aircraft;• GCR component: D(Si)→D(tissue)x5=“H*(10)”; To get as good statistical reliability as possible - all aircraft spectra

summed up and regressed for Edep above ~ 1 MeV

2. SAA: Supposed that all events are due to protons of SAA Interpretation: D(Si)→D(tissue), and D(tissue) x QFaverage calculated from energy distribution spectra

(~1.3) = “H*(10)”;


Comparison of CERF, aircraft, and spacecraft calculated spectra


Regressed aircraft energy distribution spectrum-comparison

with spacecraftsEnergy deposition spectra

y = 0.0105x-1.4294

R2 = 0.9851

0.0001

0.001

0.01

0.1

0 5 10 15 20 25Edep, MeV

Rela

tive e

nerg

y d

ep

osit

ion

dis

trib

uti

on

s

Aircraft

FOTON

ISS

power function (aircraft)


Daily values of dose quantities onboard space vehicles

Partial values

H*(10), μSv ISS Foton capsule for component GCR SAA GCR SAA low LET 99 239 40 161 neutrons 126 46 HECP 89 69 22 47 Sum up 314 308 108 208 Neutrons, % 40 42

Total values Vehicle ISS 01-MDU ISS01-TLD+TED Foton D(Si), μGy 237 - 86.7 H*(10)high, μSv 284 316 115 H*(10)tot, μSv 622 518 316 Neutrons, % 20.5 27 14.5


Further analysis of long-term measurements onboard of Czech

Airlines Aircraft

• MDU was placed on board of aircraft (A 310-300) several times in years 2001, 2002, 2005 and 2006.

• The database contains more than 41,000 records and each one contains information on: date and time, direction of flight, geographic coordinates, altitude, vertical cut-off rigidity, Apatity neutron monitor records, and dosimetric characteristics based on measurements with MDU and calculated by codes

CARI-6 and EPCARD v3.2.


Statistics of database parameters

Parameter Minimum Maximum Most frequent

value (frequency)

Altitude [feet] 20000 41000 35000

(25%)

Vertical cut-off rigidity [GV] 0 17 1÷3

(70%)

Apatity NM [counts/sec] 1020 1340 1130÷1190

(50%)


Results of analysis - 1

Cut-off rigidity dependence of dosimetric characteristics

0

1

2

3

4

5

6

7

0 2 4 6 8 10 12 14 16 18Vertical cut-off rigidity [GV]

Rat

es o

f dos

imet

ricch

arac

teris

tics

[m S

v/h]

Happ(MDU)

E(CARI-6)

H*(10)(EPCARD)

E(EPCARD)

Altitude dependence of dosimetric characteristics



00.10.20.30.40.50.60.70.80.9

1

27 28 29 30 31 32 33 34 35 36 37 38 39Altitude [1000 feet]

Ratio

of n

on-n

eutro

nan

d ne

utro

n co

ntrib

utio

ns

MDU

EPCARD v3.2

Ratio of non-neutron and neutron component of H*(10) measured with MDU and calculated with EPCARD v3.2 as function of altitude (rigidity is from interval 1÷3 GV).

Ratio of non-neutron and neutron component of Happ(MDU) and H*(10)(EPCARD) as function of rigidity (altitude 35,000 feet).

00.20.40.60.8

11.21.41.61.8

2

0 2 4 6 8 10 12 14 16 18 20Vertical cut-off rigidity [GV]

Ratio

of n

on-n

eutro

n an

d ne

utro

n co

ntrib

utio

ns

MDU

EPCARD v3.2



Geomagnetic position dependence of Edep distribution.

0

0.01

0.02

0.03

0.04

0.05

0.06

0.1 1 10 100E dep [MeV]

Re

lati

ve

D(S

i) x

Ed

ep

[M

eV

]

(1÷3) GV(5÷7) GV(15÷18) GV


Conclusions - aircraft

• Rates of dosimetric characteristics increase with ascending altitude, decrease with ascending rigidity;

• Happ(MDU) and E(CARI) values correlate well;

• Ratio of non-neutron and neutron components does not depend on the altitude but depends on the rigidity; neutron contribution is dominant below 7 GV.


FD 09/05 - comparison of MDU and Oulu neutron monitor data; corrected for the difference

Happ(MDU)/E(CARI)

-30%

-25%

-20%

-15%

-10%

-5%

0%

5%

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29September 2005; days

dev

iatio

ns

(H app - E(CARI))/E(CARI)

ONM deviation


GLE 68 – Effective dose rate estimation

Maximum of GLE intensity at 40,000 ft


General conclusions During COST 724 (WG2, WP2400) activities:• Methodology improved and new results on actual level of

exposure at different conditions and situations (flight altitude and other parameters, solar activity, shield thickness, galactic cosmic rays vs. solar component (SAA), etc., not only quantitative but also qualitative data (microdosimetry) acquired

• Several examples of correlation between Space and close-to-Earth exposure levels studied

These results would help to diminish uncertainties related to the estimation of the risk based on physical knowledge, both dosimetric as microdosimetric.

Acknowledgements

Colleagues responsible for preparation realization and exposure of detectors onboard of space vehicles, and aircraft, mainly: V.A. Shurshakov, B. Kolář, J. Starý

Colleagues from STIL BAS, and NPI AS CR, mainly : B. Tomov, P. Dimitrov, Y. Matviichuk, O. Ploc


Thank you for your attention

New results for Radiation Effects on the Human Health Obtained during the COST-724 Action F. Spurný a, Ts. Dachev b, a Nuclear Physics Institute, Czech.

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