Bologna, 2008 24th Int. Conf. Nuclear Tracks in Solid

Bologna, 200824th Int. Conf. Nuclear

Tracks in Solid

Track Core Size of Track Core Size of Proton and Heavy Ions Proton and Heavy Ions

inin PADC Detectors PADC Detectors

Tomoya YamauchiTomoya YamauchiKobe University, JapanKobe University, Japan

24th International Conference on Nuclear Tracks in Solids 1 - 5 September 2008, Bologna

Tomoya YAMAUCHI, Yutaka MORI, Keiji ODA,Tomoya YAMAUCHI, Yutaka MORI, Keiji ODA, Kobe University, Graduate School of Maritime

Sciences, 5-1-1 Fukaeminami-machi, Kobe, Japan.

Nakahiro YASUDA,Nakahiro YASUDA, National Institute of Radiological Science,

4-9-5 Anagawa, Inage-ku, Chiba, Japan.

RRéémi BARILLON,mi BARILLON,Institut Pluridisciplinaire Hubert Curien, 2

3 rue du Loess, Strasbourg, France.アンスティチュート・プリュリィディシプリネール・ユベール・キュイア



Tracks in Solid

OrganizationOrganization

Outline of the present studyOutline of the present study

• Motivation & Purpose• Tracks in PADC

•UV-method: UV-visible absorption spectra, Track overlapping model (core size)(core size)•AFM-Method: Surface observation by Atomic Force Microscope after short-time etching (core size)(core size)•IR-method: Fourier transform-IR absorption spectra, G value (chemical modification)(chemical modification)


Bologna, 200824th Int. Conf. Nuclear Tracks in S

olid

• Summary

Motivation & PurposeMotivation & Purpose

•For the development of new SSNTDs:

with higher sensitivity: 5 keV/µm >>> 0.5 keV/µm,

with controllable detection thresholds.

• To elucidate the track structure and track formation process in PADC and other polymers



olid

MaterialsMaterials

• PADC: poly(allyl diglycol carbonate) BRYOTRAK (Fukuvi Chemical Industry) / CR-39

• PC: Bisphenol A polycarbonate

Macrofol KG (Good fellow)



olid

In some physical models, track core is treated as the region where the primary or direct ionization is dominant,surrounded by the track halo or penumbra,that is produced by the secondary electrons or delta-rays.

In this work,……

What is track core?What is track core?



olid

Track core size by three different ways:

1) UV-method1) UV-method: optically modified region due to the creation of some types of damage

2) AFM-method2) AFM-method: region where the local etching rate is significantly enhanced

3) IR-method3) IR-method: region where carbonate ester bonds and ether bonds are lost

What is track core?What is track core?



olid

UV-Visible absorption spectra of UV-Visible absorption spectra of PADCPADC

Fig. 1 UV-Visible spectra of a PADC sheet and the

monomer.

Fig. 2 UV-Visible-Near IR spectra of a PADC sheet.

0

0.2

0.4

0.6

0.8

1

500 1000 1500 2000 2500 3000

Abs

orba

nce

Wavelength (nm)

C=O1st overtone

-OH, H2O

2751 nm: 3635 cm-1 : H2O anti-symmetric 2820 nm: 3550 cm-1 : OH, H2O symmetric 2880 nm: 3470 cm-1 : C=O the first overtone

0

1

2

3

4

5

200 250 300 350 400 450

unirrad.monomer

Opt

ical

Den

sity

Wavelength (nm)

C=O carbonyl

*

n *



olid

UV-methodUV-method

Irradiations were carried out using a tandem Van de Graaff accelerator at Graduate School of Maritime Sciences, Kobe Univers

ity.

Table 1. Irradiation condition.Ion

speciesIncident energy

H+ 3.4 MeV KUMS

He2+ 5.1 MeV KUMS

C4+ 8.5 MeV KUMS

O4+ 7.0 MeV KUMS



Tracks in Solid

UV-methodUV-method

UV-Visible spectra of PADC UV-Visible spectra of PADC sheets exposed to energetic sheets exposed to energetic

protons in vacuumprotons in vacuum

Fig. 3 UV-Visible spectra of PADC sheets exposed to 3.4 MeV

proton beams.

Fig. 4 UV-Visible spectra of PADC sheets exposed to 3.4 MeV proton beams at higher fluence

s.

The first peak is at 240 nm and the second one is at 280 nm.

0

0.5

1

1.5

2

2.5

3

200 250 300 350 400 450

1e125e121e132e132.5e134e138e13

Op

tica

l den

sity

Wavelength (nm)

ab

c

d

e

f

g

a

b

c

d

e

gf

fluence; ions/cm2

1st

2nd

0

1

2

3

4

5

200 250 300 350 400 450

8e131e144e146e147e14

Opt

ical

den

sity

Wavelength (nm)

gh

ijk

hg

i

k

j

Fluence; ions/cm21st

2nd



olid

UV-methodUV-method

Dependence of the peak height and peak Dependence of the peak height and peak height ratio on proton fluence: 280nm/2height ratio on proton fluence: 280nm/2

40nm40nm

Fig. 5 Changes in the absorbance at the first and the second

peaks with proton fluence.

Fig. 6 Changes in the peak height ratio with proton fluence.

The height of 1st peak decreased around 2.5x1013 ions/cm2 .

The proportionality was lost at 1.0x1013 ions/cm2 .

0

0.5

1

1.5

2

2.5

3

3.5

4

1012

1013

1014

1015

Abs

orba

nce

at p

eaks

Fluence (ions/cm2)

O.D. = const x Fluence

1st peak (240nm)

2nd peak (280nm)0

0.5

1

1.5

1012

1013

1014

1015

Pea

k he

ight

rat

io (

280n

m) / (2

40nm

)

Fluence (ions/cm2)

3.4 MeV proton



olid

UV-methodUV-method

Track overlapping and UV Track overlapping and UV absorption spectraabsorption spectra

0

1

2

3

4

200 250 300 350

Ab

sorb

an

ce

Wavelength (nm)

0

1

2

3

4

200 250 300 350

Ab

sorb

an

ce

Wavelength (nm)

Fig. 7 Without track overlapping, the optical density should be simply doubled when the fluence is doubled. Tracks are assumed to be simpl

e cylinders.

0

1

2

3

4

200 250 300 350

Ab

sorb

an

ce

Wavelength (nm)



olid

UV-methodUV-method

Track piling (random number):Track piling (random number):track radius = 3.5 nmtrack radius = 3.5 nm

Fig. 8 Evolution of track piling with fluence (simulation).

1x 1011 ions/cm2

20 n

m/d

iv.

5 x 1011 ions/cm220

nm

/div

.1 x 1012 ions/cm2

20 n

m/d

iv.

5 x 1012 ions/cm2

20 n

m/d

iv.

1 x 1013 ions/cm2

20 n

m/d

iv.

100 nm



olid

UV-methodUV-method

Pileup of Pileup of tracks (model)tracks (model)

Fig. 9 Evolution of track overlapping at various track radi

i.

Drops of

rain

Les feuilles morte

s0

0.2

0.4

0.6

0.8

1

108

109

1010

1011

1012

1013

1014

1015

1016

r = 0.2 nmr = 0.5 nmr = 1 nmr = 2 nmr = 3 nmr = 4 nmr = 5 nm

Occ

up

ied

fra

ctio

n: A

(n)

Fluence (ions/cm2)

( radius of latent track )



olid

UV-methodUV-method

Critical fluence where the overlapping Critical fluence where the overlapping becomes significantbecomes significant

Fig. 11 Relation between the critical fluence and track radi

us.

0.1

1

10

1011

1012

1013

1014

Lat

ent

trac

k r

adiu

s (n

m)

Critical fluence (ions/cm2)

C He HO



olid

0

0.2

0.4

0.6

0.8

1

1010

1011

1012

1013

1014

1015

1016

Occ

upie

d fr

acti

on

Fluence (ions/cm2)

Simple summation(proprotional to fluence)

Occupied area: A(n)

Single: A1(n)

Double: A2(n)

Triple: A3(n)

10 fold: A10

(n)

50 fold: A50

(n)

Track radius: rt = 1 nm

Fig. 10 Evolution of track overlapping with fluence.

UV-methodUV-method

Track core radius versus Track core radius versus stopping powerstopping power

Fig. 12 Relation between the track core radii and stopping p

ower from the UV method .

0

0.5

1

1.5

2

2.5

3

3.5

0 200 400 600 800 1000 1200 1400 1600

Lat

ent

trac

k ra

dius

(nm

)

Stopping power (keV/µm)

: rt = 0.048(dE/dx)0.55

by Apel et al. (1999)

: rt = 0.159(dE/dx)0.39

H

He

C

O

NIM B 208 (2003)149-154.


UV-methodUV-method


olid

HIMAC for heavier ionsHIMAC for heavier ionsHeavy Ion Medical Accelerator in ChibaHeavy Ion Medical Accelerator in Chiba

Table 2.

Ion species

Incident energy

O 8.6 MeV HIMAC

Ne 18.8 MeV HIMAC

Si 27.0 MeV HIMAC

Ar 35.0 MeV HIMAC

Fe 80.0 MeV HIMAC

Port Plaza ChibaHIMAC 共同利用研究成果発表会



Tracks in Solid

UV-methodUV-method

Fig. 13 Relation between the track core radii and stopping power from the

UV method (HIMAC).


NIM B 236 (2005)318-322.



Tracks in Solid

UV-methodUV-method

0

1

2

3

4

5

6

7

0 1000 2000 3000 4000 5000

Tra

ck r

adiu

s (n

m)


ONe

Si Ar

Fe

: rt=0.214(dE/dx)

0.38

Track core radius by UV-methodTrack core radius by UV-method


ower from the UV method.

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000

Track core radius in PADCby UV-method


Track

core

radiu

s (n

m)

H

He

C

O

O

NeArSi

Fe

rt 0.159dE

dxkeV /m

0.39

nm ,

rt 0.214dE

dxkeV /m

0.38

nm ,



olid

UV-methodUV-method

Track core radius ofTrack core radius offission fragments by fission fragments by

AFMAFM

Fig. 16 Evolution of minute etch pit of fission

fragments in the subsurface layer. The intersection on the coordinate indicates the core radius of fission fragments of about 6 nm.

0

10

20

30

40

50

60

70

80

0 10 20 30 40 50 60 70

FF

y = 6.02 + 1.0717x R= 0.99494

Pit

rad

ius

(nm

)

Etching time (sec)

RM 37 (2003)119-125.


Tracks in Solid

Fig. 15 Typical AFM images of etched PADC. The samples were

etched in 6 M KOH solution at 70 ºC for 2 min (a) and 50 s (b).


AFM-methodAFM-method

HIMAC and HIMAC and VIVITRONVIVITRON

(Strasbour(Strasbour

g)g)

Ion

species

Incident energy

O 8.6 MeV HIMAC

Ne18.8 MeV

HIMAC

Si27.0 MeV

HIMAC

Ar35.0 MeV

HIMAC

Fe80.0 MeV

HIMAC

I200.0 MeV

VIVITRON

Xe240.0 MeV

HIMAC

Au250.0 MeV

VIVITRON

Table 3.



Tracks in Solid


Track core radius by AFM-methodTrack core radius by AFM-method

Fig. 17 Etch pits of Fe ion.Etching time: 60 s.

Fig. 18 Evolution of minute etch pit of heavy ions.

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70

ONeSiArFeIXeAu

Pit

rad

ius

[nm

]

Etching Time [sec]



olid



Fig. 19 Relation between the track core radii and stopping power from the AFM and UV metho

ds.

0

5

10

15

20

0 5000 1 104 1.5 104 2 104

UV-methodONeSiAr

FeIXeAu

Tra

ck c

ore

rad

ius

(nm

)


r = 0.214(dE/dx)0.38 Track core radii from the AFM method are greater than those from the UV methods for relatively he

avier ions.

Rev FMS.KU 2 (2006)179-184.



olid


FT-IR spectra of PADCFT-IR spectra of PADC

Fig. 20 FT-IR spectra of PADC films with various

thickness.

Fig. 21 Changes in absorbance for some bands

of PADC with film thickness.

0

0.5

1

1.5

2

2.5

3

80012001600200024002800320036004000

100 1553

Ab

sorb

nac

e

Wavenumber (cm-1

)

100 (m) 15 (m)

5 (m) 3 (m)

saturated

C-O-CC=O

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40 50 60 70

Ab

sorb

ance

Thickness (m)

790 (cm-1

)

880 (cm-1

)

2955 (cm-1

)

Beer-Lambert

law



Tracks in Solid

IR-methodIR-method

Loss of carbonyl along tracks in Loss of carbonyl along tracks in PADCPADC

Fig. 22 Spectral change of PADC in IR region by Fe ion irrad

iation.

Fig. 23 Decrease of carbonate ester bonds with heavy ion flu

ence.

0.6

0.7

0.8

0.9

1.0

1.1

0 1 1012 2 1012 3 1012 4 1012 5 1012

C

Ne

Ar

Fe

Rel

ativ

e ab

sorb

ance

: A/A

0

Fluence (ions/cm2)

Carbonyl bond: 1770 cm-1

C=O

0.0

0.5

1.0

1.5

2.0

100012001400160018002000

UnirradiatedIrradiated

Abs

orba

nce

Wavenumber (cm -1)

Fe 147 MeV 1.5x1011

ions/cm2

carbonateester

C-O-C

CH2

CH2

carbonate ester

C=O

ether

C-O-C

N F N0

1 F,

A F A0

N F

N0

,

L N0 .

rt2,



olid

IR-methodIR-method

Fig. 24 Relation between the track core radii and stopping power from the IR-method (GANIL

&HIMAC).

0

1

2

3

4

5

6

7

8

0 1000 2000 3000 4000 5000 6000 7000

UV

IR

Tra

ck c

ore

rad

ius

(nm

)

Averaged LET (keV/m)

Cether

Fe: present work

O Ne

Si Ar

Fe

carbonate ester

ether

0

1

2

3

4

5

6

0 1000 2000 3000 4000 5000 6000

Eff

ecti

ve t

rack

cor

e ra

diu

s (n

m)


UV-method

Fe

Ar

Ne

C

Fig. 25 Relation between the track core radii and stopping power from the IR-method (HIMA

C).

Track core radius Track core radius by IR-methodby IR-method

JJAP 47 (2008)3606-3609.

RM 40 (2005)224-228.RM 43 (2008)S106-S110.



olid

IR-methodIR-method

Track core radius by UV, AFM and Track core radius by UV, AFM and IR methodsIR methods

Fig. 26 Relation between the track core radii and stopping power from the three methods.

0

5

10

15

20

0 5000 1 104 1.5 104 2 104

Track core radius in PADC


Track

core

radiu

s (n

m)

UV-methodKobe Univ.

UV-methodHIMAC

IR-method

AFM-method

AFM-method


discussiondiscussion


olid

Track core radius by UV, AFM and IR methods

Fig. 27 Relation between the track core radii and stopping power from the three methods.

0.1

1

10

100 1000 104

Track core radius in PADC

Track

core

rad

ius

(nm

)


UV-methodKobe Univ.

UV-methodHIMAC

IR-method

AFM-method

AFM-method



olid


Track core radius and G value (1/3)

Experimentally obtained relation:

N F N0

1 F .

Where F is fluence. At a fluence of 1 ion/cm2,

N 1 N0 N0,

N0 N0 N 1 .This indicates the number of decreased bond per unit length of one track, i.e.

damage density, L:

L N0 .



olid



G value is attained by dividing L by the average stopping power in films, .

G N0

S .

If the track core radius is proportional to the square root of stopping power,

rt aS 0.5,

rt2 a2S ,

G value was independent of the stopping power, as:

G N0

S

a2S

S a2 .

S



olid




ower.

0

2

4

6

8

10

12

14

0 5000 1 104 1.5 104 2 104

EFG

G v

alu

e (

/10

0 e

V)


Fig. 29 Relation between G value and stopping power.

0

2

4

6

8

10

0 5000 1 104 1.5 104 2 104

BCD

Track

core

rad

ius

(nm

)


rt aS 0.5

rt aS 0.5

rt aS 0.62

rt aS 0.62

rt aS 0.38

rt aS 0.38



olid


Tracks in PADC


ower in PADC.

0.0

2.0

4.0

6.0

8.0

10.0

0 2000 4000 6000 8000 10000 12000 14000

y = 0.034672 * x^(0.57099) R= 0.9938

y = 0.11691 * x^(0.3833) R= 0.98088

Tra

ck c

ore

rad

ius

(nm

)


He

C

Ne

Ar

Fe

Xe

rt 0.214dE

dxkeV /m

0.38

nm ,

rt 0.159dE

dxkeV /m

0.39

nm .

by UV method

rt aS 0.57

rt aS 0.38



olid


Tracks in PADC


ower in PADC.

0

2

4

6

8

10

12

0 2000 4000 6000 8000 10000 12000 14000

G v

alu

e (b

ond de

st/1

00 e

V)

Stopping power (keV/m)

He

C

Ne

Ar Fe Xe

Fig. 31 Relation between the G value for loss of C=O and stop

ping power in PADC (1).

0.0

2.0

4.0

6.0

8.0

10.0

0 2000 4000 6000 8000 10000 12000 14000

y = 0.034672 * x^(0.57099) R= 0.9938

y = 0.11691 * x^(0.3833) R= 0.98088

Tra

ck c

ore

rad

ius

(nm

)


He

C

Ne

Ar

Fe

Xe



olid


Tracks in PADC


ping power in PADC (2).

2

4

6

8

10

12

0 2000 4000 6000 8000 10000 12000 14000

G v

alue

(bo

ndd

est/1

00eV

)

Stoping power (keV/µm)

He

C

Ne

Ar Fe Xe

rCO 0.0347dE

dxkeV /m

0.57

nm .

rCO 0.117dE

dxkeV /m

0.38

nm .

0.0

2.0

4.0

6.0

8.0

10.0

0 2000 4000 6000 8000 10000 12000 14000

y = 0.034672 * x^(0.57099) R= 0.9938

y = 0.11691 * x^(0.3833) R= 0.98088

Tra

ck c

ore

rad

ius

(nm

)


He

C

Ne

Ar

Fe

Xe


ower in PADC.



olid

G value = 17 (/100eV) for gamma-ray !!




olid

Summary 1/2Summary 1/2

Higher G values at lower stopping power in PADC not

in PC


Good selections of the molecule structure between two carbonate ester bonds

can provide us sufficient polymers for SSNTDs.



olid

Thank you for your attention!

Grazie!



olid

G valueG value: ICRU report 60, 1998: ICRU report 60, 1998 Fundamental Quantities and Units for Ionizing Radiation

• The radiation chemical yield, G(x), of an entity, x, is the quotient of n(x) by , where n(x) is the mean amount of substance of that entity produced, destroyed, or changed in a system by the energy imparted, , to the matter of that system, thus,

Unit: mol J-1

G x n x

.

The related quantity, called G value, has been defined as the number of entities produced, destroyed or changed by an energy imparted of 100 eV. The unit in which the G value is expressed is (100 eV)-1. A G value of 1 (100 eV)-1 corresponds to a radiation chemical yield of 0.104 µmol J-1.

ICRU: International Commission on Radiation Units ICRU: International Commission on Radiation Units and Measurementsand Measurements



olid

Occupied area by tracks: A(n)Occupied area by tracks: A(n)at fluence of n (ions/cmat fluence of n (ions/cm22), track area o), track area o

f sf s

Fig. 10 Fraction of the occupied area by tracks.

Probability

A(n-1) fall into the occupied area

1-A(n-1)fall into the non-occupied area

A(n) A(n 1) s 1 A n ,A n 1 1 s n

.



olid

N-folds area by tracks: AN-folds area by tracks: ANN(n)(n)

A n 1 1 s n,

A n 1 exp sn A1 n A2 n A3 n AN n

A1 n sn exp sn ,

A2 n sn 2

2

exp sn ,

A3 n sn 3

6

exp sn ,

AN n sn N

N!

exp sn ,

Fig. 11 Evolution of track overlapping

with fluence.Poisson

distribution

0

0.2

0.4

0.6

0.8

1

1010

1011

1012

1013

1014

1015

1016

Occ

upie

d fr

acti

on

Fluence (ions/cm2)

Simple summation(proprotional to fluence)

Occupied area: A(n)

Single: A1(n)

Double: A2(n)

Triple: A3(n)

10 fold: A10

(n)

50 fold: A50

(n)

Track radius: rt = 1 nm



olid

Determination of the critical fluences Determination of the critical fluences for He and Cfor He and C

Fig. 13 Changes in the absorbance at the first and the second peaks with helium ion fluenc

e.

Fig. 14 Changes in the absorbance at the first and the second peaks with carbon ion fluenc

e.

0

0.5

1

1.5

2

2.5

1011

1012

1013

1014

Abs

orba

nce

at p

eaks

Fluence (ions/cm2)

1st peak (240nm)

2nd peak (240nm)

O.D. = constant x fluence

He

0

0.5

1

1.5

2

2.5

3

1011

1012

1013

1014

Abs

orba

nce

at p

eaks

Fluence (ion/cm2)

C

O.D. = constant x Fluence



olid

Determination of the critical fluencesDetermination of the critical fluences

Fig. 15 Changes in the absorbance at the first and the second peaks with oxygen ion fluenc

e.

Fig. 16 Changes in the peak height ratio with ion fluence.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1011

1012

1013

1014

Pea

k he

ight

rat

io (2

80nm

) / (240

nm)

Fluence (ions/cm2)

O

C

He

H

0

0.2

0.4

0.6

0.8

1

1011

1012

1013

1014

O

Abs

orba

nce

at p

eaks

Fluence (ions/cm2)

O.D. = constant x fluence



olid

AFM-method AFM-method without etchingwithout etching

Tracks of 80 MeVAu ion in PMMA



olid

AFM-methodAFM-methodOLYMPUS NanoVision 2000

0

200

400

600

800

1000

1200

0 500 1000 1500 2000

FFAlpha

Pit

rad

ius

(nm

)

Etching time (sec)

Vb = 2.5 µm/h

optical microscope

Fig. 21 Etch pit radii for fission fragments and alpha-particles as a function of the etch

ing time.



olid

RM 37 (2003)119-125.

0

2

4

6

8

10

0 5000 1 104 1.5 104 2 104 2.5 104

Lat

ent

trac

k r

adiu

s (n

m)


rt = 0.048(dE/dx)0.55

by Apel (1999)

: rt = 0.159(dE/dx)0.39

F.F. by AFM

HHe

C

O

Fig. 23 Assessed latent track radial size in PADC plastics for light ions and fission fragment indicating as a function

of stopping power.

Track core Track core radius by IR-radius by IR-

methodmethod

Fig. 31 Relation between the track core radii and stopping power from the IR-method (GANIL

&HIMAC).

0

1

2

3

4

5

6

7

8

0 1000 2000 3000 4000 5000 6000 7000

UV

IR

Tra

ck c

ore

rad

ius

(nm

)

Averaged LET (keV/m)

Cether

Fe: present work

O Ne

Si Ar

Fe

carbonate ester

ether

GANIL: Grand Accelerateur National d’Ions Lourds



olid

Track core radius in PC

0.1

1

10

100

0 5000 10000 15000 20000

Tra

ck c

ore

rad

ius

(nm

)


NiAu UF

O

AuXeAlkyne Amorphization

present work

AmorphizationAlkyne

rCO 0.0378dE

dxkeV /m

0.55

nm .

Fig. 33 Relation between the track core radii and stopping power in PC from various method

s.Rev FMS.KU 4 (2006)61-70.



olid

Tracks in PC

0

1

2

3

4

5

6

7

0 2000 4000 6000 8000 10000 12000

y = 0.040687 * x^(0.53848) R= 0.99783

Eff

ecti

ve t

rack

cor

e ra

diu

s (n

m)


He

C

Ne

Ar

FeFe

fitting curve

0

1

2

3

4

5

0 2000 4000 6000 8000 10000 12000

G v

alu

e (C

=O

dest/1

00eV

)


He

NeCAr Fe

Fe


ower in PC.


ping power in PC.

Almost independent of stopping power



olid

Tracks in PADC

Fig. 41 Radial dose distribution of energy deposited around

the path of heavy ions in PC. Fig. 42 Radial dose distribution of energy deposited around the path of heavy ions in PAD

C.

104

105

106

107

108

109

0.1 1 10

Loc

al d

ose

(Gy)

Distance from the ion's path (nm)

CNe

ArFe

Xe

PC

104

105

106

107

108

109

0.1 1 10

Loc

al d

ose

(Gy)

Distance from the ion's path (nm)

CNe

Ar Fe

proton 1 MeV

Effective track core radius of C ion

PADC



olid

Gamma-irradiated PADC

Fig. 41 Decrease of the relati

ve absorbance with gamma-dose. Fig. 42 G value for loss of carbonate ester bonds in gamma and heavy ion irradiated PADC.



olid

0.6

0.7

0.8

0.9

1

1.1

0 200 400 600 800 1000 1200

C=OC-O-C

Rel

ativ

e ab

sorb

ance

: A/A

0

Absorsed dose (kGy)

0

5

10

15

20

0 2000 4000 6000 8000 10000 12000 14000

G v

alue

(bo

ndd

est/1

00 e

V)

Stopping pawer (keV/m)

C Ne

FeXe

Ar

He

Gamma-ray

• A review was given for the present status of our study on track core radii for proton and heavy ions in PADC.

• Evaluated core radii were dependent on the methods: UV, AFM, and IR-methods.

rUV rIR rAFM



olid


Documents

Bologna, 2008 24th Int. Conf. Nuclear Tracks in Solid