D E S I R E Dose Estimation by Simulation of the ISS Radiation Environment Geant4 simulations of the Columbus/ISS radiation

D E S I R EDose Estimation by Simulation of the ISS Radiation Environment

http://www.particle.kth.se/desire/

Geant4 simulations ofthe Columbus/ISS radiation environment

T. Ersmark1, P. Carlson1, E. Daly2, C. Fuglesang3, I. Gudowska4, B. Lund-Jensen1,R. Nartallo2, P. Nieminen2, M. Pearce1, G. Santin2, N. Sobolevsky5

1Royal Institute of Technology (KTH) (Stockholm)2ESA-ESTEC (Noordwijk)

3EAC/JSC (Cologne/Houston)4Karolinska Institutet (Stockholm)

5Institute for Nuclear Research (Moscow)

SPENVIS and Geant4 Workshop, Leuven, 051006, Tore Ersmark (KTH) 2/19

Outline

1. The DESIRE project

2. Geant4 physics validation studies

3. Columbus and ISS geometries

4. Radiation environment models

5. Simulation results

6. Conclusions and future


The DESIRE project

• ”Dose Estimation by Simulation of the ISS Radiation Environment”• Aimed at accurate calculations of the radiation flux and doses to

astronauts inside the European ISS laboratory Columbus.• Utilizes Geant4 for radiation transport.• Funded by ESA (15613/NL/LvH) and SNSB.

1. Validation and comparisons of Geant4 physics models to…– Experiments– NASA BRYN-/HZETRN programs– SHIELD-HIT Monte Carlo program

2. Implementation of Columbus and ISS geometries in Geant4.3. Evaluation of incident radiation environment models.4. Full simulations of particle fluxes and doses inside Columbus.


Geant4 physics validation studies

• Incident protons with energies 10-1000 MeV.– Neutron production

– Energy deposition

– Proton penetration

– Water, Beryllium, Carbon,Aluminum, Iron, Uranium

• Comparisons to Los Alamosexperimental data (Meier,Nucl. Sci. Eng. 102 and 104),SHIELD-HIT, BRYNTRN.

• Published in IEEE Trans. Nucl. Sci. 51,1378 (2004).

Summary: Energy deposition/proton penetration ok. Secondary neutron production ok after release of cascade models (since 2003).

113 MeV p on 4 cm Al 256 MeV p on 12 cm Al


Columbus and ISSgeometries

• “Columbus1”– Simple cylinder-like geometry– 10 volumes; MDPS1/2/3 + hull– 4200 kg

• “Columbus3”– Detailed geometry– 800 volumes– 16750 kg

• ISS– 350-400 volumes– 352 tons (369 tons)

...so 4 combinations


The ISS Geant4 geometry

Geant4

JSC/SEMDA spec.

Hull ...

Interior ...

Cabin ...

... (CAM)


The “Columbus3” Geant4 geometry


Radiation environment models

• Studied incident radiation fields– Trapped protons (isotropic and anisotropic)– GCR protons– SPE protons– (Cosmic ray albedo neutrons)– (Trapped electrons)

• Other radiation fields– GCR ions– Solar ions

• 51.6 330, 380, 430 km orbit

• Web interfaces to models– SPENVIS (”SPV”) (http://www.spenvis.oma.be/spenvis/)– CREME96 (”C96”) (https://creme96.nrl.navy.mil)– SIREST (”SRS”) (http://sirest.larc.nasa.gov)


Incident spectra

Incident particle spectra at 380 km and solar min

• Belt protons

• GCR protons

• SPE protons

• CR albedo neutrons

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

SPV AP8

SPV PSB97SPV CRRESPRO, max

C96 GCR pSRS GCR p

C96 SPE p (worst day)C96 SPE p (worst week)

SRS albedo neutrons


Belt proton altitude dependence and anisotropy

Incident proton spectra at 330 km, 380 km, 430 km

• Solar minimum/maximum

• Anisotropy; spectra for protons coming from port and startboard-backward (at solar-minimum and 380 km)

Energy (MeV)

-110 1 10 210 310

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-110 1 10 210 310

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-610

-510

-410

-310

-210

-110

1

10

210

310 330 km, min

330 km, max380 km, min380 km, max430 km, min

430 km, maxUP (stb-bwd)UP (port)

VF1 (stb-bwd)VF1 (port)


Simulation results

• Spectra of particles enteringColumbus

• Doses at 10 mm depthin ICRU sphere– Statistics...

• 380 km andsolar minimumunless noted


Belt protons

Incident belt (AP8-MIN) protons at 380 km. Penetrating protons and neutrons.

Belt proton doses at three altitudes for different geometry configurations.

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310Incidentp, Col1noISSn, Col1noISSp, Col1withISSn, Col1withISS

p, Col3noISSn, Col3noISSp, Col3withISS

n, Col3withISS

Col1noISS Col1withISS Col3noISS Col3withISSCol1noISS Col1withISS Col3noISS Col3withISS

Gy/

d)

D

ose

ra

te (

0

100

200

300

400

500

600

700

800

900

1000


Gy/

d)

D

ose

ra

te (

0

100

200

300

400

500

600

700

800

900

1000

330 km altitude380 km altitude

430 km altitude


On-going study ofbelt proton anisotropy

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310Incident average

Incident stb-bwdIncident port

p, stb-bwdp, port

Spectra for protons coming from

• port

• startboard-backward

SPENVIS AP8

Anisotropy model ”UP” (Badhwar/Konradi)


Cosmic ray protons

Penetrating primary/secondary protons and secondary neutrons due to incident cosmic ray protons (CREME96-min, 380 km)

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310Incidentp, Col1noISSn, Col1noISSp, Col1withISSn, Col1withISS

p, Col3noISSn, Col3noISSp, Col3withISS

n, Col3withISS


Cosmic ray protons; Col3withISS

Spectra of various particle species entering Columbus in the ”Col3withISS” geometry

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310IncidentProtons

NeutronsPhotonsLeptons

Mesons


Cosmic ray proton doses


Gy/

d)

D

ose

ra

te (

0

10

20

30

40

50

60

70

80

90

100


Gy/

d)

D

ose

ra

te (

0

10

20

30

40

50

60

70

80

90

100

All

Protons

NeutronsPhotonsLeptons

Mesons

Ions

Dose rates in ICRU sphere due to incident cosmic ray protons;itemized by geometry model and particle type at surface of sphere


Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310Incidentp, Col1noISS

n, Col1noISSp, Col1withISS

n, Col1withISSp, Col3noISS


n, Col3withISS

SPE protons & albedo neutrons

Col1noISS

Col1withISS

Col3noISS

Col3withISS

Col1noISS

Col1withISS

Col3noISS

Col3withISS

Do

se r

ate

(m

Gy/

d)

0

2

4

6

8

10

12

14

Col1noISS

Col1withISS

Col3noISS

Col3withISS

Col1noISS

Col1withISS

Col3noISS

Col3withISS

Do

se r

ate

(m

Gy/

d)

0

2

4

6

8

10

12

14

SPE particle spectra and resulting doses Albedo neutron spectra and secondary protons

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310Incidentp, Col1noISS


n, Col1withISSp, Col3noISS


n, Col3withISS


Modell comparisons; Col3withISS

Belt p (AP8) Belt p (PSB97) GCR p (C96) GCR p (SRS) Albedo nBelt p (AP8) Belt p (PSB97) GCR p (C96) GCR p (SRS) Albedo n

Gy/

d)

D

ose

ra

te (

0

100

200

300

400

500

600

Belt p (AP8) Belt p (PSB97) GCR p (C96) GCR p (SRS) Albedo nBelt p (AP8) Belt p (PSB97) GCR p (C96) GCR p (SRS) Albedo n

Gy/

d)

D

ose

ra

te (

0

100

200

300

400

500

600 • Belt protons: 135 vs. 520 Gy/d (!)

• CR protons: 60 vs. 115 Gy/d

• Albedo neutrons unimportant (several previous studies)

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

Energy (MeV)

-210 -110 1 10 210 310 410 510

)-1

s-1

sr

-2 c

m-1

Flu

x (M

eV

-910

-810

-710

-610

-510

-410

-310

-210

-110

1

10

210

310

SPV AP8

SPV PSB97

SPV CRRESPRO, maxC96 GCR p

SRS GCR p

C96 SPE p (worst day)

C96 SPE p (worst week)

SRS albedo neutrons


Conclusions and future

• A detailed model of Columbus and ISS (14A) has been implemented as Geant4 geometries.

• Dose rates has been calculated for standard incident radiation field models– Belt protons (AP8-MIN): 135 Gy/d– Cosmic ray protons (CREME96, min): 60 Gy/d– Cosmic ray albedo neutrons (SIREST): 0.5 Gy/d

• Study of the influence of belt proton anisotropy in progress.

GCR- and solar ions will be studied the next few months.

Documents

D E S I R E Dose Estimation by Simulation of the ISS Radiation Environment Geant4 simulations of the Columbus/ISS radiation