Applications in Heavy Ion Radiolysis

Jay A. LaVerneRadiation Laboratory and Department of Physics

University of Notre Dame

Funded by: Division of Chemical Sciences, Geosciences, and BiosciencesOffice of Basic Energy SciencesU. S. Department of Energy

Fundamental Basis to Applications

Examine energy loss, charge and other properties of ionizing radiation.

Elucidate fundamental radiolytic decomposition of molecules and the kinetics of the transients.

physics chemistry medicine / engineering / environment

50 MeV C6+ ions in air

Notre Dame Radiation Laboratory

Elucidate fundamental radiolytic decomposition of molecules and the kinetics of the transients

Examine problems relevant to nuclear energy

3 electron accelerators (2-8 MeV)3 gamma sources (0.3-24 kCi)

Gamma source

Electron linac

Notre Dame Radiation Laboratory

Radiation Effects in Nuclear Power Industry

Waste Storage Power Plant Chemistry

Fuel ProcessingWaste Transport

Radiation effects are found throughout the nuclear energy complex.

Wide variation in type of radiation.

How will materials decompose due to radiation?

Can we design materials more radiation robust?

Heavy Ion Radiolysis in Space

solar/cosmic radiation: H, He, etc.planetary particles

Applications in space exploration and origin of life.

Exploration

Communication

Space travel

Solar Flares

Health / Therapy Effects due to Track Structure

Precise dose delivery with heavy ions

Cancer therapyDNA damage

Energy Deposition

Ion Characteristics

Notre Dame has a core set of ion accelerators.Each ion has a different track structure, physics and chemistry.

10-1 100 101 102 103 104 10510-1

100

101

102

103

104

105

electron

58Ni

238U

12C

4He1H100

5020

10MeV/amu = 5

Sto

ppin

g P

ower

in W

ater

(eV

/nm

)

Ion Energy (MeV)

FN Tandem

Radiolysis cell

-100-50

050

100

-50

0

50

100

150

-50

0

50100

150

Z A

xis

(nm

)

Y Axis (nm)X Axis (nm)

-100-50

050

100

-50

0

50

100

150

-50

050

100150

Z A

xis

(nm

)

Differences in 10 keV Track Segments at 1 ps

10 MeV 1H

5 MeV 4He

eaq-

H+

OH H H2

OH-

H2O2

Notre Dame Heavy Ion Beamline

Gamma Radiolysis

Water and Aqueous Solutions

H2O eaq-, H3O+, OH, H, H2, H2O2

Water radiolysis cell

Measure the products of water radiolysis under realistic conditions.

eaq- : dissolution, H2 formation

H2 : explosive, flammable

OH : biological

H2O2 : corrosive

Water Decomposition

Radiation effects are generally over within a microsecond.

e-

eaq- H2 + O

H2O

H2O++

proton transfer hydration (100 fs)

OH + H3O+

(H2O)* thermalization solvation (250-300 fs)

ionization

radical reactions (0.1 ns - 1s)

H + OH

OH Radical Yields

H2O eaq-, H3O+, OH, H, H2, H2O2

Track structure determines radiation chemistryYields and models used for medical therapy

1 10 100 1000

0.1

1

770 ns77 ns

7.7 ns

-rays

12C

4He

1HG

i(OH

) (m

olec

ules

/100

eV

)

Stopping Power in Water (eV/nm)

Motivation for Radiolysis of Organic Compounds

Applications:

Hydrocarbons: tissue, oils, lubricants

Polymers: lithography, masks, reactor components, space environment, waste storage

Resins: separations, reactors

Basic Science: elucidate fundamental radiation decomposition mechanisms in nonaqueous media

Benzene/iodine radiolysis

H2 Yields in Monomers and Polymers

100 101 102 1030.01

0.1

1

10

polystyrene

polyethylene

hexane

benzene

-ray 12C4He1H

G(H

2) (m

olec

ules

/100

eV

)

Track Average LET (eV/nm)

Chang, LaVerne and Araos Radiat. Phys. Chem. 2001, 60, 253.

polyethylene

polystyrene

C

H

C

H

H

H

C

H

C

H

H

Many studies on simple liquids and polymers

Radiolysis of Ion Exchange Resins

Nuclear ReactorsSeparations

Resins are important in separation waste streams and in reactor water purification.

Exactly how do they decompose with radiation?

How do they hold up under radiation stress?

Can we make them functional but radiation robust?

Resins

10 kGy 50 kGy 100 kGy

H2 Yields with Amberlite Resins

OH- > Cl- > NO3-

1 10 100 10000.01

0.1

1

12C

4He

1H-rays

Amberlite IRA400

NO-3

Cl-OH-

G(H

2) (m

olec

ules

/100

eV

)

Track Average LET (eV/nm)

CH CH2

CH2

N+

Cl-

H3C

CH3

CH3

n

Amberlite IRA400

Resin radiolysis is vital in the nuclear power industry, but can be deadly.

Interfacial Radiolysis

H2O + SiO2 , ZrO2, CeO2, TiO2, UO2

water – ceramic oxides – radiation

H2

oxide

oxide

water

4He ion radiolysis of CeO2

Radiation effects at water – solid interfaces are responsible for corrosion.

H2 initiativeWaste transport / storageFuel rod integrityReactor engineering

Summary

University based accelerators are important for examination of radiation effects.

Studies evolve as problems arise.

Applications:

nuclear power industrymedical therapyspace study and explorationhomeland security

Simplified Radiation Chemistry of Water

H2O H + OH

OH + OH H2O2

H + H H2

OH + S Product

H + S Product

OH

OH

H

H

S