Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators
The problem of the radiation resistance of the carbon stripper foils is considered. The short review of the experimental data available in literature and original experimental results of the authors are presented. In the paper discussed is the possibility of composite fulleren based carbon films to...
Збережено в:
| Дата: | 2001 |
|---|---|
| Автори: | , , , , , |
| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2001
|
| Назва видання: | Вопросы атомной науки и техники |
| Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/79006 |
| Теги: |
Додати тег
Немає тегів, Будьте першим, хто поставить тег для цього запису!
|
| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators / A.V. Vasin, L.A. Matveeva, G.N. Kozeratskaya, A.V. Rusavsky, Yu.I. Totsky, I.N. Vishnevsky // Вопросы атомной науки и техники. — 2001. — № 5. — С. 154-156. — Бібліогр.: 13 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
irk-123456789-79006 |
|---|---|
| record_format |
dspace |
| spelling |
irk-123456789-790062015-03-25T03:01:48Z Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators Vasin, A.V. Matveeva, L.A. Kozeratskaya, G.N. Rusavsky, A.V. Totsky, Yu.I. Vishnevsky, I.N. The problem of the radiation resistance of the carbon stripper foils is considered. The short review of the experimental data available in literature and original experimental results of the authors are presented. In the paper discussed is the possibility of composite fulleren based carbon films to be used for preparation of the stripper foils. Some technological methods for preparation of composite fulleren based carbon films are proposed. Raman scattering and atom force microscopy were used for investigation of the fulleren and composite films deposited by evaporation of the C60 fulleren powder. 2001 Article Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators / A.V. Vasin, L.A. Matveeva, G.N. Kozeratskaya, A.V. Rusavsky, Yu.I. Totsky, I.N. Vishnevsky // Вопросы атомной науки и техники. — 2001. — № 5. — С. 154-156. — Бібліогр.: 13 назв. — англ. 1562-6016 PACS number: 29.17.+w http://dspace.nbuv.gov.ua/handle/123456789/79006 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
The problem of the radiation resistance of the carbon stripper foils is considered. The short review of the experimental data available in literature and original experimental results of the authors are presented. In the paper discussed is the possibility of composite fulleren based carbon films to be used for preparation of the stripper foils. Some technological methods for preparation of composite fulleren based carbon films are proposed. Raman scattering and atom force microscopy were used for investigation of the fulleren and composite films deposited by evaporation of the C60 fulleren powder. |
| format |
Article |
| author |
Vasin, A.V. Matveeva, L.A. Kozeratskaya, G.N. Rusavsky, A.V. Totsky, Yu.I. Vishnevsky, I.N. |
| spellingShingle |
Vasin, A.V. Matveeva, L.A. Kozeratskaya, G.N. Rusavsky, A.V. Totsky, Yu.I. Vishnevsky, I.N. Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators Вопросы атомной науки и техники |
| author_facet |
Vasin, A.V. Matveeva, L.A. Kozeratskaya, G.N. Rusavsky, A.V. Totsky, Yu.I. Vishnevsky, I.N. |
| author_sort |
Vasin, A.V. |
| title |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| title_short |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| title_full |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| title_fullStr |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| title_full_unstemmed |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| title_sort |
potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2001 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79006 |
| citation_txt |
Potentiality of the composite fulleren based carbon films as the stripper foils for tandem accelerators / A.V. Vasin, L.A. Matveeva, G.N. Kozeratskaya, A.V. Rusavsky, Yu.I. Totsky, I.N. Vishnevsky // Вопросы атомной науки и техники. — 2001. — № 5. — С. 154-156. — Бібліогр.: 13 назв. — англ. |
| series |
Вопросы атомной науки и техники |
| work_keys_str_mv |
AT vasinav potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators AT matveevala potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators AT kozeratskayagn potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators AT rusavskyav potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators AT totskyyui potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators AT vishnevskyin potentialityofthecompositefullerenbasedcarbonfilmsasthestripperfoilsfortandemaccelerators |
| first_indexed |
2025-07-06T03:08:04Z |
| last_indexed |
2025-07-06T03:08:04Z |
| _version_ |
1836865327085912064 |
| fulltext |
POTENTIALITY OF THE COMPOSITE FULLEREN BASED CARBON
FILMS AS THE STRIPPER FOILS FOR TANDEM ACCELERATORS
A.V. Vasin1, L.A. Matveeva1, G.N. Kozeratskaya2, A.V. Rusavsky2, Yu.I. Totsky2,
I.N. Vishnevsky2
1 Institute of Semiconductor Physics of NASU
03028, Кyiv-28, Pr. Nauki, 45, Ukraine
matveeva@isp.kiev.ua
2 Institute for Nuclear Research of NASU,
03028, Кyiv-28, Pr. Nauki, 47, Ukraine
interdep@inr.kiev.ua
The problem of the radiation resistance of the carbon stripper foils is considered. The short review of the experi-
mental data available in literature and original experimental results of the authors are presented. In the paper dis-
cussed is the possibility of composite fulleren based carbon films to be used for preparation of the stripper foils.
Some technological methods for preparation of composite fulleren based carbon films are proposed. Raman scatter-
ing and atom force microscopy were used for investigation of the fulleren and composite films deposited by evapor-
ation of the C60 fulleren powder.
PACS number: 29.17.+w
1 INTRODUCTION
Solid state stripper foils (SSSF) for the tandem ac-
celerators have some advantages in comparison with gas
targets. For instance the use of the SSSF provides the
higher average charge state of ions and hence higher
output energy or, often more impotent, allow the higher
beam intensity at a given energy. Carbon stripper foils
are normally used as stripper foils because they are
stable at a high temperature in vacuum, and have the
good electrical and thermal conductivity. To keep the
multiple scattering small, low Z materials must be used
and carbon is one of the lowest-Z materials that can be
fabricated as a thin film suitable for this purpose.
But there is one very impotent disadvantage. Carbon
foils have a limited lifetime due to radiation damage.
The rate of damage is proportional to ion beam intensity
and ion mass. The factors that limit the lifetime of the
foil are: (i) increasing of the film thickness and (ii)
tightening of the films in the irradiation area [1] that
leads to rupturing of the stripper. As will be shown be-
low all these factors are the consequence of irradiation
stimulated structure reconstruction in carbon films.
2 EXPERIMENT
Till end of the 70-th of the last century the main
technologies for preparation of free-standing carbon
films were arc and electron beam evaporation of graph-
ite. But in 1979 the collaboration of the groups from
The Daresbury Laboratory and Atom Energy Agency
had resulted in development of the chemical vapour de-
position (CVD) technology for preparation of hydrogen-
ated carbon stripper foils. [1-3]. The lifetime of those
foils was improved by the factor of order. At the same
time the first systematic investigation of the irradiation
effect on the structure reconstruction in such hydrogen-
ated amorphous carbon films was performed [4, 5]. The
conclusion was made that under ion bombardment the
thermally activated graphitization process (ordering of
the graphite-like structure) takes place. The authors
have explained improved radiation resistance of such
films by modification of the short-range order with ion
bombardment during the deposition process.
Within the 80-th in the Munich technical university
researchers made a very comprehensive and complex
study of the influence of the short-range order peculiar-
ities (such as distribution of the orientation of the graph-
ite-like nanocrystallites, GLN) on the carbon stripper
foil radiation resistance [6, 7]. The crystalline structure
of graphite is extremely anisotropic. Carbon atoms are
very closely packed in basic planes (graphen sheets) by
strong covalent bonds. But graphen sheets are bonded
together by weak Van-der-Vaals forces. Interatomic dis-
tance in graphen sheets is about 0.14 nm while the dis-
tance between graphen sheet is more than 0.3 nm. The
level of anisotropy was estimated by the ratio of the in-
tensity of the electron diffraction reflections I002/I100.
They had proposed and substantiated the following
mechanism of the stripper foils destruction under heavy
ions bombardment. Usual deposition methods such as
arc and electron beam evaporation results in formation
of films with structure having preferable orientation of
the graphen sheets in GLN parallel to the film plane.
Under ion bombardment the dissipation of the ion en-
ergy due to the stopping power leads to heating the car-
bon material in the irradiated region and hence to the
graphitization process. Due to existence of the initial
texture the graphitized regions also have a preferable
orientation. The accumulation of interstitials between
graphene sheets and diffusion of vacancies to the
boundary of the nanocrystallits lead to the well-known
effect of expansion along the c-axis and compression in
the base plane.[8]. It is obvious that carbon films having
the texture of the c-axis of the GLN perpendicular to the
film plain will be compressed and eventually crack.
When the orientation of the GLN is isotropic then the
effect of the anisotropic changes of the volume of the
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 154-156.
154
GLN is compensated.
They had developed the laser ablation technology
for deposition carbon films and showed that these films
have a nearly isotropic structure and improved radiation
resistance in comparison with CVD films [6].
In our previous paper it was showed that the level of
the isotropy of the amorphous carbon structure could be
successively varied by intensity of the ion bombardment
during the deposition process [9].
But the nature has given us an almost entirely iso-
tropic carbon material. This is fulleren. Fulleren is a
general name of the wide family of the carbon closed
molecules that had been revealed about ten years ago
[10]. The most stable are C60 and C70 molecules having
60 and 70 carbon atoms respectively (Fig. 1). In solid
state this molecules exist in the form of cubic molecular
crystals (fullerits). This structure is very isotropic in
comparison with graphite-like structure of the usual
amorphous carbon films. It is very attractive idea to es-
timate potentiality of a such material for stripper foils.
But on the first steps one runs into some hard problems.
1. Fullerens have a low sublimation temperature
(about 500OC). It makes very simple the evapora-
tion process but it is known that the temperature of
the irradiated zone of the stripper foil could reach
1000OC and so pure fullerene films could not oper-
ate at such temperature.
2. Despite a great progress in the technology of
fullerene production in large quantities the price of
the commercially available fullerens is still very
high (about 35-45 dollars per gram for pure C60
powder).
C60 C70
Fig. 1. Fulleren molecules C60 and C70.
First problem could be avoided in two ways. It is
possible to fabricate the “sandwich” structure: amorph-
ous carbon/fulleren/amorphous carbon (Fig. 2). Due to
their large size (diameter about 0.7 nm) fulleren mo-
lecules could not diffuse to the surface of the film
through amorphous carbon and sublimate. To reduce the
prices of the films it is possible to use fulleren enriched
carbon soot as an evaporated fulleren material.
Fig. 2. “Sandwich” structure a-C/C60/a-C.
Another possible structure is the composite films
composed of fulleren agglomerates embeded in an
amorphous carbon matrix. Such structure could be pre-
pared by code position of amorphous carbon (arc or
electron evaporation) and fullerens (sublimation). But as
things turned out the more simple method is available.
We have investigated the structure of the films de-
posited by thermal evaporation of the pure C60 powder
in dependence of the deposition rate. Pure C60 powder
was sublimated from the tantalum effusion cell at the
temperature of about 600OC. One silicon substrate was
located at a distance of 4 cm from the tantalum cell. An-
other substrate was located at a distance of 10 cm from
the evaporator. Such a deposition configuration allows
us to produce samples deposited under the same condi-
tions but other deposition rate. Deposition rates were
about 0.5 µm/min and 0.1 µm/min for the different sub-
strates.
Raman scattering (RS) spectroscopy was used for
characterisation of the nanostructure of the films. Mor-
phology of the surface of the films was analysed by
means of atom force microscopy.
RS spectra of the films are presented in Fig. 3. The
RS spectrum of the film deposited at a lower rate is typ-
ical for pure C60 films and consists of three lines at 1426
cm-1, 1470 cm-1 and 1578 cm-1 (Fig. 3, spectrum 1) that
could be unambiguously ascribed to the “intramolecu-
lar” vibration modes with symmetry Hg, Ag and Hg [11,
12].
1200 1400 1600 1800
Ramen shift, cm
Fig. 3. Raman spectra of the films deposited at low-
er (1) and higher (2) diposition rate.
RS spectra of the film deposited at higher deposition
rate is more complicated (Fig. 3, spectrum 2). The broad
bands with the centres of about 1400 cm-1 and 1600 cm-1
are associated with D (“disordered”) and G (“graphitic”)
bands respectively of the amorphous carbon with graph-
ite-like short-range order. The narrow line at the 1470
cm-1 is an evidence that the film contains C60 molecules
(Ag mode).
In Fig. 4 the atom force microscopy image of the
surface morphology of the two different carbon films
are presented. One could see that the morphology of the
surface of the films is quite different as well as the Ra-
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 155-156.
155
man spectra. Surface of the pure fulleren films is com-
posed of agglomerates of the fulleren molecules that is
typical for the nanocrystalline fulleren films. Surface
morphology of the composite a-C/C60 film is rougher
and something similar to the morphology of the
amorphous carbon films deposited by dc-magnetron
sputtering [9].
This results allow to conclude that 1) at the high de-
position rate fulleren molecules could be collapsed into
graphite-like nanocrystallites; 2) composite structure a-
C/C60 with different phase composition could be suc-
cessively prepared by varying the deposition rate during
fulleren sublimation.
X – 200 nm/div.
Z – 50 nm/div
X – 500 nm/div
Z – 300 nm/div
Fig. 4. AFM image of the surface morphology of the
films deposited at low (a) a high (b) deposition rate.
It is obvious that further research is necessary to ex-
amine real operation properties of these films including
radiation resistance against heavy ion bombardment.
Radiation damage most likely will leads to collapse of
C60 molecules into graphite-like clusters. But one may
expect that graphen sheets in new carbon clusters will
be preferably oriented along the incident ion beam [6,
7]. Radiation damage in such a structure does not results
in compression and rupture of the film.
3 CONCLUSION
The first estimation of the potentiality of the fulleren
based composite carbon films as stripper foils for tan-
dem accelerators was made. Some technological meth-
ods for preparation of fulleren based composite carbon
films are proposed.
REFERENCES
1. D.S.Whitmell, B.H.Armitage, D.W.L.Tolfree,
N.R.S.Tait // Nucl. Instr. and Meth. 1979, v. 159,
p. 605.
2. N.R.S.Tait, D.W.L.Tolfree, D.S.Whitmell and
B.H.Armitage // Nucl. Instr. and Meth. 1979,
v. 163, p. 1.
3. B.H.Armitage, D.S.Whitmell, N.R.S.Tait,
D.W.L.Tolfree // Nucl. Instr. and Meth. 1979,
v. 163, p. 277.
4. N.R.S.Tait // Nucl. Instr. and Meth. 1981, v. A 184,
p. 206.
5. U.Sander and H.H.Bukow // Radiation effects.
1979, v. 40, p. 143.
6. G.Dollinger, P.Mier-Komor, A.Mitwalsky // Nucl.
Instr. and Meth. 1991, v. A 303, p. 79.
7. G. Dollinger and P. Mier-Komor // Nucl. Instr. and
Meth. 1989, v. A 282, p. 223.
8. Т.N.Shurshakova, Yu.S.Virgilyev, I.P.Kalyagina //
Atomnaya Ehnergiya. 1976, v. 5, p. 399 (in Russi-
an).
9. А.V.Vasin, E.N.Mozhzhukhin, G.N.Kozeratskaya,
A.V.Rusavsky, Y.I.Totskyю // Scientific papers of
the Institute for Nuclear Research (Kiev, Ukraine).
2000, v. 1, p. 98.
10. R.E. Smoly // UFN. 1998, v. 3, p. 324.
11. P.H.M Van Loosdrecht, P.J.M. Van Bentum,
M.A.Verheijen et. al. // Chem. Phys. Letters. 1992,
v. 6, p. 587.
12. R.Liu, M.V.Klein // Phys. Rev. B. 1992, v. 19,
p. 11437.
13. Hisao-chu Tsai, D.B.Bogy. // J.Vac.Sci.Technol.
1987, v. А. 6, p. 3287.
156
|