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Interaction of GeV heavy ions with solids — first results at ganil
120
INTERACTION
Nuclear Instruments and Methods in Physics Research B19/20 (1987) 120-122 North-Holland, Amsterdam
O F GeV H E A V Y I O N S W I T H S O L I D S - F I R S T R E S U L T S A T G A N I L *
E. B A L A N Z A T , J. D U R A L , J.C. J O U S S E T a n d M. T O U L E M O N D E Centre [nterdisciplinaire de Recherches avec les Ions [wards (CIRIL), Bd Henri Becquerel, BP 5133, 14040 Caen Cedex, France
The Grand Acc616rateur National d'Ions Lourds (GANIL) of Caen, France, accelerates ions from C to U in the energy range from 100 MeV/amu to 10 MeV/amu. The Centre Interdisciplinaire de Recherches avec les Ions Lourds (CIRIL) is in charge of the non-nuclear facilities and assists, at GANIL, the physicists of both atomic physics and condensed matter physics. Irradiation facility and first typical results for condensed matter physics are presented. Influence of electronic stopping power for the ion irradiation induced effects in organic and inorganic materials and amorphous metallic alloys is shown.
The Grand Accrlrrateur National d'Ions Lourds (.GANIL) of Caen, France, is made of a series of three cyclotrons which accelerate ions from carbon, at 100 M e V / a m u up to uranium, at 10 M e V / a m u with intensifies of 10x°-10t2p/s. Ten percent of the beam time is devoted to both atomic physics and condensed matter physics. Experimental facilities as well as main topics and first typical results of condensed matter physics are presented here. In fig. 1, the maximum energies of G A N I L ions are plotted versus the atomic number in the present situation and for the future modification of G A N I L scheduled for the be$inning of 1989. Moreover, the decision of building up a medium energy line (in between the two main cyclotrons) has also been taken. This line will deliver, in 1989, ions from 15 MeV/amu, for the lightest, up to 5 M e V / a m u , for the heaviest (fig. 1) during 100% of the beam time for non-nuclear physics purposes. 1) The two main interests of such energetic heavy ions in materials science are the very high value of the energy losses by electronic interactions a n d the millimetric ranges of these ions in matter. Fig. 2a shows a typical example for the energy losses of 1.8 GeV Ar, 2.9 GeV Kr and 3.0 GeV Xe ions in an yttrium iron garnet. It can be seen that the rate of the electronic stopping power ( - d E / d x ) e goes from 100 eV/,~, to 3 keV/A. Moreover, the ratio "electronic losses/elastic collision losses" is very high, around 2000 (fig. 2b) whatever the ion at sufficiently high energy. The effect of electronic stopping power can, consequently, be studied in the purest manner. The millimetric ranges allow to study stacks of samples thick enough ( - 10/zm) to be representative of the *Experiment performed at the National Laboratory GANIL, Caen, France. 0168-583X/87/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
I0[ WMax (HeY/A) 81]
\ \ \ \
\
\ \\
FUTURE
61] \
\
\, \ \ \
40
PRESENT
\\
\\ \\\\\\\\x
20
0
0
~
20
40
_
60
80
Z
Fig. 1. Maximum energy of the GANIL ions vs the atomic number. The dashed line corresponds to a project planned to be achieved in 1989. MEL: Medium energy line (1989).
bulk. With such stacks the effect of many different rates of ( - d E / d x)e can be explored keeping identical all the other conditions of the irradiation. 2) The irradiation facility consists mainly of a 77 K cryostat, where the stacks of samples are cooled by a low pressure of He gas, and a beam profile definition system made of slits and beam intensity monitors. The beam can be made homogeneous, at better than 10%, on an area of 30 x 30 mm 2 by means of a magnetic sweeping device. Typical features of this facility are ion flux
E. Balanzat et aL / Interaction o/heavy ions with solids
~.~ z
al. [4] has been extensively studied: track diameter variations with ( - d E / d x ) e have been measured by both methods. A threshold, for ( - d E / d x ) e , has been clearly deduced from the results [5].
@
Xe 23 MeV/A
121
b) Polymers I
r35MeV/A
~-~_ 10 E ........
f-"
~ t '
'
'
I
Ar44MeV/A '
I
'
~' .................... I . . . . I ' '
'
'
I
. . . .
Kr
I
'
T
'
'
,I .' .'. .'
The purpose of these experiments is to observe the modifications induced by ions in simple linear polymers such as
'
Ar~ polyethylene
@
x
polyvinylidenefluoride (PVDF)
~o2
polytetrafluoroethylene (PTFE)
101 200
400
600
Rp -X(micron)
Fig. 2. (a) Variation of the electronic stopping power ( - d E /dx)cvs (Rp-x)* for 1.8 GeV Ar, 2.7 GeV Kr and 3.0 GeV Xe in yttrium iron garnet. (b) Variation of the ratio (electronic stopping power/nuclear stopping power) vs (Rp-x)* of ions for the same cases as in (a).*Rp-x is the residual range. The ion enters from the right of the diagram. of 108-109 ions/cm2s at irradiation temperature lower than 90 K. All these equipments are of course, open to the international community*. 3) Since the first beam of GANIL, in 1983, the most of the topics have been related to the effects of excitation electronic losses in matter and dealt essentially with insulators although, however, also with a few exotic conductors (organic, amorphous metals, silicon and so on). It must be emphasized that all these experiments are now in progress and all are not older than thirty months. The results presented here are preliminary resuits and many of the references, private communications.
a) Ferrimagnetic oxides Yttrium iron garnet Y3FesO12 and barium hexaferrites BaFel2019 have been irradiated at 77 K by At, Kr and Xe ions in the GeV range. The details of the experiment are presented in these Proceedings [1]. Induced tracks along the ion path have been evidenced both by Mbssbauer spectrometry [2] and by transmission electron microscopy [3]. So, the effect of electronic losses in these materials previously shown by Hansen et *Request for experimental proposal can be sent to CIRIL.
(HH) (.F) FF) -C-CH H
.
-C-CH F
.
-C-CF F
."
and
The first step consists of characterizing the induced modifications by infrared absorption spectroscopy (IRAS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). The second step will be to determine the elementary mechanisms which are involved in the absorption of ion energy by electronic excitations. The first results are presented in these Proceedings [6]. It is underlined here, as a typical example, the observation, with the XPS method, on 800 MeV oxygen ions irradiated PVDF samples, of the creation of allen bonding type simultaneously with the desorption of HF.
c) Amorphous metallic alloys The irradiation of amorphous metallic alloys of PdSi and FeB type have been extensively studied in the last decade [7]. The alloys were irradiated by 2.5 MeV electrons [8], fission fragments of boron (Li, 0.9 MeV and He 1.6 MeV) [9], fission fragments of uranium [10,11], 300 MeV Kr and Xe ions [12]. In the case of the light particles the induced effects are the creation of defects close to the Frenkel defects type of crystalline metals. On the other hand, for heavy ions very important variation of electrical resistance [11] and of sample dimensions perpendicular to the beam direction [13] were observed. The energies of these ions (a few hundred MeV) were too low to allow to distinguish between the effects of elastic collisions events (the only effect for the light particles) and electronic excitation losses effects. 90 K irradiations by 1.8 GeV At, 2.7 GeV Kr and 3.0 GeV Xe of a Fe85Bx5 amorphous alloy have been performed at GANIL [14]. Variations of the electrical I. BASIC PROCESSES
E. Balanzat et al. I Interaction of heaoy ions with solids
122 00[
(3.
I
(-dE/dx)e
I
Fe85B15 90K irradiations 77K measurements
50C
/ / tQ / i
0 rr rr
/ i t / •
400 t
t
i
' •
30C
Xe
/ /
i
/
i
value equal to 14 MeV/amu. Above this value it has also been observed that the dimensional variations were important and could explain, at least by order of magnitude, the observed effect on the electrical resistance [13]. In conclusion, the experiments presented here clearly show an important effect of high enough electronic stopping power in matter and that this effect is strongly dependent on the value of these electronic losses. With a tool as G A N I L / C I R I L it can be hoped that a step forward in our knowledge of elementary processes induced in the ion energy absorption by matter will be made.
it /
200
it
i /
/
I
t
References
i
i
100
l°Bf.f. ,/Ar ,,o'"Kr /
0 It----tiP . . . . . r ~
0
10
,
I
20
3JO
'
40
(dE/dX)e(MeV/pm) Fig. 3. Variation of ((AR/Ro)/dpa)) vs (-dE/dx)¢ for an amorphous Fes5 B15 alloy; ((,5 R/R o)/dpa)) is explained in the text. The curve is drawn to guide the eye. e from [8]; l°B from [9]; At', Kr, Xe: our experiment.
resistance of samples, piled up in stacks along the beam direction were measured at 77 K in function of the ion fluence ~ t during frequent beam stops. The results have been plotted in fig. 3 as the variation of ( A R / R o ) / d p a vs ( - d E / d x ) e where R o is the initial electrical resistance, AR the increase of R 0 after an ion irradiation of fluence ~t, dpa the proportion of atomic elastic displacements during an irradiation ~t, dpa has been calculated using a WSS [15] cross section and a modified Kinchin and Pease model [16] and it has been verified that the primary knocked atoms spectra are pretty close for the three Ar, Kr and Xe irradiations: the dpa parameter is relevant to compare elastic effects in these three irradiations. In fig. 3 it is clear that ( A R / R o ) / d p a is not at all constant as it would be if the induced effects were due to atomic elastic collisions. On the contrary, ( A R / R o ) / d p a increases drastically above a threshold
[1] F. Studer, D. Groult, N. Nguyen and M. Toulemonde, these Proceedings (IBMM '86) Nucl. Instr. and Meth. B19/20 (1987) Section VI. [2] M. Toulemonde, G. Fuchs, D. Groult, N. Nguyen and F. Studer, private communication. [3] F. Studer, private communication. [4] P. Hansen, H. Heitman, P.M. Smit, Phys. Rev. B26 (198)) 3539. [5] G. Fuchs, F. Studer, E. Balanzat, D. Groult, M. Toulemonde and J.C. Jousset, Europhys. Lett., in press. [6] A. LeMoel, J.P. Duraud, J. Lemaire, E. Balanzat, J.M. Ramillon and C. Damez, these Proceedings (IBMM '86) Nucl. Instr. and Meth. B19/20 (1987) Section VI. [7] J. Hillairet, E. Balanzat, A. Audouard and J.C. Jousset, Ann. de Claim. 9 (1984) 103. [8] A. Audouard, J. Balogh, J. Dural and J.C. Jousset, J. Non-Cryst. Solids 50 (1982) 71 and Radiat. Eft. 62 (1982) 161. [9] A. Audouard, J. Dural, J.C. Jousset and D. Lesueur, C.R. Acad. Sc. 297 (1983) 647. [10] D. Lesueur, Radiat. Eft. 24 (1975) 201. [11] A. Audouard and J.C. Jousset, J. Phys. (Paris) C9 (1982) 423. [12] A. Audouard, A. Benyagoub, L. Thome and J. Chaumont, J. Phys. F15 (1985) 1237. [13] S. Klaumunzer, G. Schumacher, Ming-Dong Hou and G. Vogl, 5th Int. Conf. on rapidly quenched materials (Elsevier Science, Amsterdam, 1985) vol. 1, p. 895. [14] A. Audouard, E. Balanzat, G. Fuchs, J.C. Jousset, D. Lesueur and L. Thome, Europhys. Lett., in press. [15] K.B. Winterbon, P. Sigmund and J.B. Sanders, K. Dan. Vidensk. Selsk. Mat. Fys. Medd. 37 (14) (1970). [16] N.J. Norgett, M.T. Robinson and I.M. Torrens, Nucl. Eng. and Design 33 (1975) 50.
INTERACTION
Nuclear Instruments and Methods in Physics Research B19/20 (1987) 120-122 North-Holland, Amsterdam
O F GeV H E A V Y I O N S W I T H S O L I D S - F I R S T R E S U L T S A T G A N I L *
E. B A L A N Z A T , J. D U R A L , J.C. J O U S S E T a n d M. T O U L E M O N D E Centre [nterdisciplinaire de Recherches avec les Ions [wards (CIRIL), Bd Henri Becquerel, BP 5133, 14040 Caen Cedex, France
The Grand Acc616rateur National d'Ions Lourds (GANIL) of Caen, France, accelerates ions from C to U in the energy range from 100 MeV/amu to 10 MeV/amu. The Centre Interdisciplinaire de Recherches avec les Ions Lourds (CIRIL) is in charge of the non-nuclear facilities and assists, at GANIL, the physicists of both atomic physics and condensed matter physics. Irradiation facility and first typical results for condensed matter physics are presented. Influence of electronic stopping power for the ion irradiation induced effects in organic and inorganic materials and amorphous metallic alloys is shown.
The Grand Accrlrrateur National d'Ions Lourds (.GANIL) of Caen, France, is made of a series of three cyclotrons which accelerate ions from carbon, at 100 M e V / a m u up to uranium, at 10 M e V / a m u with intensifies of 10x°-10t2p/s. Ten percent of the beam time is devoted to both atomic physics and condensed matter physics. Experimental facilities as well as main topics and first typical results of condensed matter physics are presented here. In fig. 1, the maximum energies of G A N I L ions are plotted versus the atomic number in the present situation and for the future modification of G A N I L scheduled for the be$inning of 1989. Moreover, the decision of building up a medium energy line (in between the two main cyclotrons) has also been taken. This line will deliver, in 1989, ions from 15 MeV/amu, for the lightest, up to 5 M e V / a m u , for the heaviest (fig. 1) during 100% of the beam time for non-nuclear physics purposes. 1) The two main interests of such energetic heavy ions in materials science are the very high value of the energy losses by electronic interactions a n d the millimetric ranges of these ions in matter. Fig. 2a shows a typical example for the energy losses of 1.8 GeV Ar, 2.9 GeV Kr and 3.0 GeV Xe ions in an yttrium iron garnet. It can be seen that the rate of the electronic stopping power ( - d E / d x ) e goes from 100 eV/,~, to 3 keV/A. Moreover, the ratio "electronic losses/elastic collision losses" is very high, around 2000 (fig. 2b) whatever the ion at sufficiently high energy. The effect of electronic stopping power can, consequently, be studied in the purest manner. The millimetric ranges allow to study stacks of samples thick enough ( - 10/zm) to be representative of the *Experiment performed at the National Laboratory GANIL, Caen, France. 0168-583X/87/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)
I0[ WMax (HeY/A) 81]
\ \ \ \
\
\ \\
FUTURE
61] \
\
\, \ \ \
40
PRESENT
\\
\\ \\\\\\\\x
20
0
0
~
20
40
_
60
80
Z
Fig. 1. Maximum energy of the GANIL ions vs the atomic number. The dashed line corresponds to a project planned to be achieved in 1989. MEL: Medium energy line (1989).
bulk. With such stacks the effect of many different rates of ( - d E / d x)e can be explored keeping identical all the other conditions of the irradiation. 2) The irradiation facility consists mainly of a 77 K cryostat, where the stacks of samples are cooled by a low pressure of He gas, and a beam profile definition system made of slits and beam intensity monitors. The beam can be made homogeneous, at better than 10%, on an area of 30 x 30 mm 2 by means of a magnetic sweeping device. Typical features of this facility are ion flux
E. Balanzat et aL / Interaction o/heavy ions with solids
~.~ z
al. [4] has been extensively studied: track diameter variations with ( - d E / d x ) e have been measured by both methods. A threshold, for ( - d E / d x ) e , has been clearly deduced from the results [5].
@
Xe 23 MeV/A
121
b) Polymers I
r35MeV/A
~-~_ 10 E ........
f-"
~ t '
'
'
I
Ar44MeV/A '
I
'
~' .................... I . . . . I ' '
'
'
I
. . . .
Kr
I
'
T
'
'
,I .' .'. .'
The purpose of these experiments is to observe the modifications induced by ions in simple linear polymers such as
'
Ar~ polyethylene
@
x
polyvinylidenefluoride (PVDF)
~o2
polytetrafluoroethylene (PTFE)
101 200
400
600
Rp -X(micron)
Fig. 2. (a) Variation of the electronic stopping power ( - d E /dx)cvs (Rp-x)* for 1.8 GeV Ar, 2.7 GeV Kr and 3.0 GeV Xe in yttrium iron garnet. (b) Variation of the ratio (electronic stopping power/nuclear stopping power) vs (Rp-x)* of ions for the same cases as in (a).*Rp-x is the residual range. The ion enters from the right of the diagram. of 108-109 ions/cm2s at irradiation temperature lower than 90 K. All these equipments are of course, open to the international community*. 3) Since the first beam of GANIL, in 1983, the most of the topics have been related to the effects of excitation electronic losses in matter and dealt essentially with insulators although, however, also with a few exotic conductors (organic, amorphous metals, silicon and so on). It must be emphasized that all these experiments are now in progress and all are not older than thirty months. The results presented here are preliminary resuits and many of the references, private communications.
a) Ferrimagnetic oxides Yttrium iron garnet Y3FesO12 and barium hexaferrites BaFel2019 have been irradiated at 77 K by At, Kr and Xe ions in the GeV range. The details of the experiment are presented in these Proceedings [1]. Induced tracks along the ion path have been evidenced both by Mbssbauer spectrometry [2] and by transmission electron microscopy [3]. So, the effect of electronic losses in these materials previously shown by Hansen et *Request for experimental proposal can be sent to CIRIL.
(HH) (.F) FF) -C-CH H
.
-C-CH F
.
-C-CF F
."
and
The first step consists of characterizing the induced modifications by infrared absorption spectroscopy (IRAS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). The second step will be to determine the elementary mechanisms which are involved in the absorption of ion energy by electronic excitations. The first results are presented in these Proceedings [6]. It is underlined here, as a typical example, the observation, with the XPS method, on 800 MeV oxygen ions irradiated PVDF samples, of the creation of allen bonding type simultaneously with the desorption of HF.
c) Amorphous metallic alloys The irradiation of amorphous metallic alloys of PdSi and FeB type have been extensively studied in the last decade [7]. The alloys were irradiated by 2.5 MeV electrons [8], fission fragments of boron (Li, 0.9 MeV and He 1.6 MeV) [9], fission fragments of uranium [10,11], 300 MeV Kr and Xe ions [12]. In the case of the light particles the induced effects are the creation of defects close to the Frenkel defects type of crystalline metals. On the other hand, for heavy ions very important variation of electrical resistance [11] and of sample dimensions perpendicular to the beam direction [13] were observed. The energies of these ions (a few hundred MeV) were too low to allow to distinguish between the effects of elastic collisions events (the only effect for the light particles) and electronic excitation losses effects. 90 K irradiations by 1.8 GeV At, 2.7 GeV Kr and 3.0 GeV Xe of a Fe85Bx5 amorphous alloy have been performed at GANIL [14]. Variations of the electrical I. BASIC PROCESSES
E. Balanzat et al. I Interaction of heaoy ions with solids
122 00[
(3.
I
(-dE/dx)e
I
Fe85B15 90K irradiations 77K measurements
50C
/ / tQ / i
0 rr rr
/ i t / •
400 t
t
i
' •
30C
Xe
/ /
i
/
i
value equal to 14 MeV/amu. Above this value it has also been observed that the dimensional variations were important and could explain, at least by order of magnitude, the observed effect on the electrical resistance [13]. In conclusion, the experiments presented here clearly show an important effect of high enough electronic stopping power in matter and that this effect is strongly dependent on the value of these electronic losses. With a tool as G A N I L / C I R I L it can be hoped that a step forward in our knowledge of elementary processes induced in the ion energy absorption by matter will be made.
it /
200
it
i /
/
I
t
References
i
i
100
l°Bf.f. ,/Ar ,,o'"Kr /
0 It----tiP . . . . . r ~
0
10
,
I
20
3JO
'
40
(dE/dX)e(MeV/pm) Fig. 3. Variation of ((AR/Ro)/dpa)) vs (-dE/dx)¢ for an amorphous Fes5 B15 alloy; ((,5 R/R o)/dpa)) is explained in the text. The curve is drawn to guide the eye. e from [8]; l°B from [9]; At', Kr, Xe: our experiment.
resistance of samples, piled up in stacks along the beam direction were measured at 77 K in function of the ion fluence ~ t during frequent beam stops. The results have been plotted in fig. 3 as the variation of ( A R / R o ) / d p a vs ( - d E / d x ) e where R o is the initial electrical resistance, AR the increase of R 0 after an ion irradiation of fluence ~t, dpa the proportion of atomic elastic displacements during an irradiation ~t, dpa has been calculated using a WSS [15] cross section and a modified Kinchin and Pease model [16] and it has been verified that the primary knocked atoms spectra are pretty close for the three Ar, Kr and Xe irradiations: the dpa parameter is relevant to compare elastic effects in these three irradiations. In fig. 3 it is clear that ( A R / R o ) / d p a is not at all constant as it would be if the induced effects were due to atomic elastic collisions. On the contrary, ( A R / R o ) / d p a increases drastically above a threshold
[1] F. Studer, D. Groult, N. Nguyen and M. Toulemonde, these Proceedings (IBMM '86) Nucl. Instr. and Meth. B19/20 (1987) Section VI. [2] M. Toulemonde, G. Fuchs, D. Groult, N. Nguyen and F. Studer, private communication. [3] F. Studer, private communication. [4] P. Hansen, H. Heitman, P.M. Smit, Phys. Rev. B26 (198)) 3539. [5] G. Fuchs, F. Studer, E. Balanzat, D. Groult, M. Toulemonde and J.C. Jousset, Europhys. Lett., in press. [6] A. LeMoel, J.P. Duraud, J. Lemaire, E. Balanzat, J.M. Ramillon and C. Damez, these Proceedings (IBMM '86) Nucl. Instr. and Meth. B19/20 (1987) Section VI. [7] J. Hillairet, E. Balanzat, A. Audouard and J.C. Jousset, Ann. de Claim. 9 (1984) 103. [8] A. Audouard, J. Balogh, J. Dural and J.C. Jousset, J. Non-Cryst. Solids 50 (1982) 71 and Radiat. Eft. 62 (1982) 161. [9] A. Audouard, J. Dural, J.C. Jousset and D. Lesueur, C.R. Acad. Sc. 297 (1983) 647. [10] D. Lesueur, Radiat. Eft. 24 (1975) 201. [11] A. Audouard and J.C. Jousset, J. Phys. (Paris) C9 (1982) 423. [12] A. Audouard, A. Benyagoub, L. Thome and J. Chaumont, J. Phys. F15 (1985) 1237. [13] S. Klaumunzer, G. Schumacher, Ming-Dong Hou and G. Vogl, 5th Int. Conf. on rapidly quenched materials (Elsevier Science, Amsterdam, 1985) vol. 1, p. 895. [14] A. Audouard, E. Balanzat, G. Fuchs, J.C. Jousset, D. Lesueur and L. Thome, Europhys. Lett., in press. [15] K.B. Winterbon, P. Sigmund and J.B. Sanders, K. Dan. Vidensk. Selsk. Mat. Fys. Medd. 37 (14) (1970). [16] N.J. Norgett, M.T. Robinson and I.M. Torrens, Nucl. Eng. and Design 33 (1975) 50.