Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing
Spectra of radioluminescence of plastic scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene under
 an influence of γ-radiation are obtained. It is shown that the most effective quenchers are macroradicals, on
 which a transmission of excitation energy from “initial”...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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| Дата: | 2006 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2006
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| Цитувати: | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing / N.I. Voronkina, V.G. Senchyshyn, V.K. Milinchuk, I.P. Sheluhov // Вопросы атомной науки и техники. — 2006. — № 3. — С. 145-147. — Бібліогр.: 4 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860108200356872192 |
|---|---|
| author | Voronkina, N.I. Senchyshyn, V.G. Milinchuk, V.K. Sheluhov, I.P. |
| author_facet | Voronkina, N.I. Senchyshyn, V.G. Milinchuk, V.K. Sheluhov, I.P. |
| citation_txt | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing / N.I. Voronkina, V.G. Senchyshyn, V.K. Milinchuk, I.P. Sheluhov // Вопросы атомной науки и техники. — 2006. — № 3. — С. 145-147. — Бібліогр.: 4 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Spectra of radioluminescence of plastic scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene under
an influence of γ-radiation are obtained. It is shown that the most effective quenchers are macroradicals, on
which a transmission of excitation energy from “initial” luminescent additives occurs. The ways to increase PS radiating
stability are proposed.
Получены спектры радиолюминесценции пластмассовых сцинтилляторов на основе полистирола и поли-2,4-диметилстирола при воздействии на них γ-излучения. Показано, что наиболее эффективными тушителями являются макрорадикалы, на которые происходит перенос энергии возбуждения с первичной люминесцирующей добавки. Предложены способы повышения радиационной стойкости ПС.
Одержано спектри радіолюмінесценції пластмасових сцинтиляторів на основі полістиролу та полі-2,4-
диметилстиролу під дією γ-випромінювання. Показано, що найбільш ефективними гасниками є
макрорадикали, на які відбувається перенос енергії збудження з первинної люмінесціючої домішки.
Запропоновано способи підвищення радіаційної стійкості ПС.
|
| first_indexed | 2025-12-07T17:32:29Z |
| format | Article |
| fulltext |
RADIOLUMINESCENCE DEGRADATION OF SCINTILLATORS
ON A BASIS OF POLYSTYRENE AND POLY-2,4-DIMETHYLSTYRENE,
THE WAYS OF THEIR RADIATING STABILITY INCREASING
N.I. Voronkina, V.G. Senchyshyn, V.K. Milinchuk, I.P. Sheluhov
Institute for scintillation materials NANU
E-mail: sench@isc.kharkov.com
Spectra of radioluminescence of plastic scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene un-
der an influence of γ-radiation are obtained. It is shown that the most effective quenchers are macroradicals, on
which a transmission of excitation energy from “initial” luminescent additives occurs. The ways to increase PS radi-
ating stability are proposed.
PACS: 29.40.Mc
1. INTRODUCTION
It is known that many factors have an influence on
decrease of the plastic scintillators (PS) light output due
to ionizing radiations; these factors are: type and rate of
radiation, temperature, environment, etc. Therefore, it is
difficult to compare data on PS radiation resistance giv-
en in literature. Besides, different authors give values of
PS light output change, measured after different time
since the termination of irradiation. "Post-radiation"
transformation can occur to some extent in scintillators
in that period [1].
In order to estimate the influence of radiation on PS
scintillation properties more correctly, degradation of
PS radioluminescence (RL) from the absorbed doze is
investigated in present work on radioluminescence spec-
tra which were registered under continuous γ-irradiation
by a specially created installation.
The installation consists of a drum with samples,
placed near 60Co-source (60,000 g-equivalent radium ac-
tivity, the absorbed doze rate being 3 Gy/s.) in canyon;
systems of fibers transmitting scintillation signal from
the sample on photomultiplier-100, located behind a
lead shield; systems of device communication SKVU-
100 from the PC. Concentration of macroradicals was
determined by EPR spectra, spectra of absorption with
the help of "Specord-M40" spectrophotometer.
2. RESULTS AND DISCUSSION
As active additives p – diphenyl phenylene (РТ) of
2% mass and 1,4-di/2-(5-fenyloxazolyl)/benzene (РО-
РОР) of 0,1% are used in them. Series of samples of
various structures have been measured. Degradation of
radioluminescence was estimated on curves of spectra
relative intensity dependence on the absorbed doze
(Fig.2). (PBD – 2-(4-diphenylyl)-5-phenyl-oxazole-
1,3,4; TPB 1,1,4,4 – especially if one takes into account
smaller density of tetraphenylbutadiene; MBD – 2-
metyl-5(p-diphynylyl)-oxadiazole-1,3,4).
Apparently, this dependence has a complex charac-
ter and depends on PS structure and γ -irradiation doze.
It is established that RL degradation is strongest at
dozes up to 40 kGy. For larger absorbed dozes, the
curves of degradation of PS with various luminescent
additives (LA) differ insignificantly but depend on a
polymeric matrix nature. PS based on poly-2,4-
dimethylstyrene show more radiation resistance than
that on the basis of polystyrene with the same LA.
Fig.1. Curves of degradation of scintillation composi-
tions radioluminescence: p-dmst (1, 2) and pst (3, 4, 5):
1 – PBD(5%)+POPOP(0,1%);
2 - PT(2%)+POPOP(0,1%);
3 - PT(2%)+POPOP(0.1%);
4 - PBD(2%)+TPB(0.1%); 5 –
MBD(2%)+POPOP(0.1%)
Mechanisms of radiochemical processes resulting in
damages of polymers and scintillators on their basis
have been already investigated. It has been shown that
primary products formed by radiolysis (ions, ions - radi-
cals, short-lived radicals, and captured electron) turn
into long-living (about several months) macroradicals
under the action of temperature and light quanta. It was
revealed that basically macroradicals with a broken
chain (an end radical Re) are stabilized in polystyrene,
and alkyl-type macroradicals of "middle" type are in p-
2,4-dmst [2, 3].
During the research of absorption spectra of the irra-
diated polymers we observed an increase in optical den-
sity in the 310…350 nm range. The comparison of de-
pendences of paramagnetic centers accumulation, the
increase in optical density and intensity of luminescence
from the absorbed doze, and also a symbate decrease of
these parameters during the "post-radiating" period have
allowed identification of the strips of absorption caused
by various macroradicals. Apparently, absorption of
macroradicals lies in the field of luminescence of initial
LA and in the field of absorption of secondary LA.
Thus, the probability of transmission of energy of elec-
tronic excitation (TEE) from initial LA on macroradi-
cals instead of secondary LA is large.
According to known Ferster-Galanin's formulas TEE
calculations in the investigated polymeric systems have
been carried out taking into account products of radioly-
sis.
kdd( R ) = 1/τ0D(R0/R)6,
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p. 145-147. 145
mailto:sench@isc.kharkov.com
∫ −= νννεν
π
dI
Nn
qФR A
u
D
D 4
45
0
26
0 )()(
128
10ln9000 .
Table 1. Absorption spectra of macroradicals in PST
and p-2,4-dmst
Polymer λmax ε, M-1,sm-1
Polystyrene 316. (e)
328.344 (m)
470.522
104
~130
Poly-2,4-
dimethylstyrene
330-340 (m)
482
2·103
~200
Table 2. Calculated average critical radii of elec-
tronic excitation energy transport in γ-irradiated PS
Polystyrene Poly-2,4-dimethyl-
styrene
Donor Accep-
tor Ro, Å Donor Accep-
tor Ro, Å
M* R.
c, R.
к 0,6 M* R.
c, R.
к 18,6
РТ R.
к 22,3 РТ R.
c 17,8
M* Op 28,2 M* Op 28,2
Op РТ 7,6
where M*− the excited macromolecule; Op − oxygen-
containing products of radiolysis; qoD
-− [4]
As follows from the calculations, TEE from the ex-
cited macromolecules of polystyrene effectively occurs
in oxygen-containing products of radiolysis by the in-
ductive - resonant mechanism. TEE on macroradicals
occurs from initial LA. In p-2,4-dmst TEE on macrorad-
icals effectively occurs both from the excited macro-
molecules and from initial LA.
The probability of TEE on macroradicals increases
according to their accumulation with absorbed doze
(τ0PT = 1.43⋅ns) [4].
As macroradicals have a competitive affect on exci-
tation energy capture, it is logical to assume that the in-
creasing of concentration of the initial additive will pro-
mote the increase of PS radiation resistance
Table 3. Dependence of speed constant of energy trans-
fer from PT on macroradicals from a dose
D, kGy CR ⋅103, M K⋅10-9, m-1⋅c-1
5 0.5 0.7
20 1.0 6.3
45 5.0 140.0
60 10.2 720.0
We have carried out an experiment with LA which is
well dissolved in polystyrene. Apparently the depen-
dence has maximum at 4…6% of weights; the further
increase in concentration of the additive reduces in-
creasing in a system degradation, probably because of
concentrating quenching.
A large role in formation and disappearance of
macroradicals plays a molecular oxygen participating in
intermediate reactions by the scheme:
R. + О2 → ROO,
ROO + HR → ROOH + R,
ROO + R → products of radiolysis,
R + R → products of radiolysis
Results of researches on influence of the molecular
oxygen dissolved in polymeric matrix are presented in
[3]. The induction period, which we have found out in
accumulation of macroradicals, indicates a positive role
of О2 in preservation of stability of scintillation proper-
ties. Reactions with the participation of oxygen are dif-
fusion-limited and depend on the permolecular structure
of matrix that is on the density of molecular balls and on
the mobility of macrochains. After the expenditure of
the oxygen dissolved in the polymeric matrix, there is
an intensive accumulation of macroradicals with the si-
multaneous diffusion of О2 from air with small speed
D~1.5.10-9sm2s-1. For acceleration of the diffusion pro-
cesses before the reaction of oxygen with macroradicals,
we incorporated various plasticizers (stearin, palmitic,
threedecan acids) into PS with a standard set of LA. We
have received PS with substantial increasing of radia-
tion resistance up to 30…40 kGy doze (Fig.2) under the
investigated doze rate. At low doze rates the range of
preservation of high radiation resistance will extend, if
the velocity of radicals formation will be comparable to
that of diffusion of О2 from air.
To increase radiation resistance of PS irradiated by
large dozes, we incorporate 10% of isopropyldiphenyl
(IPD). Under ionizing radiation this combination easily
forms radicals (it is less radiation-resistant than lumi-
nescent additives), which recombine with macroradi-
cals, thus protecting the polymer from destruction. The
results, which prove such a protective mechanism, are
shown in Fig.2. Interaction of radicals of isopropy-
ldiphenyl with macroradicals of polystyrene proves to
be true by comparison of luminescence spectra of super-
precipitate samples of PS before and after γ-irradiation
(Fig.2).
Fig.2. Curves of degradation of scintillation composi-
tions radioluminescence:
1) pst+PT(2%)+POPOP(0.1%)+IPD(10%);
2) pst+PT(2%)+POPOP(0,1%)+TDA (0.2%);
3) p-2,4-dmst+PT(2%)+POPOP(0.1%);
4)pst+PT(2%)+POPOP(0.1%)
In fluorescence spectra of samples with IPD a typi-
cal for biphenyl groups spectrum is observed, spectra
are not found out in standard PS from this area, as dur-
ing the superprecipitate luminescent additives are
washed out from the polymer.
Thus, we have proved that basic centers of PS radio-
luminescence quenching are macroradicals, especially
the end radical Re: ~CH2-C6H5-CH. Rather large radia-
tion stability of PS based on p-2,4-dmst is explained by
the fact that in p-2,4-dmst macroradicals of "middle"
type are stabilized in a greater degree: ~CH2-
C6H5(СН3)2-C~, which are conformationally more ac-
cessible to reactions with oxygen and other radicals.
146
Fig.3. Spectra of fluorescence of γ-irradiated scintilla-
tion compositions on the basis of polystyrene:
1 - PT(2%) + POPOP(0.1%) before superprecipitate;
2 – the same after superprecipitate;
3 - PT(2%)+POPOP(0.1%)+IPB(10%) after superpre-
cipitate
CONCLUSION
The experimental data obtained and their interpreta-
tion enable to draw the following conclusions regarding
the increase in radiation resistance of polymeric scintil-
lation compositions:
1. In the region of absorbed dozes up to 20…
30 kGy:
- Selection of LA, which luminescence area is not
blocked by the area of absorption of the formed macro-
radicals;
- Increasing of diffusion rate of molecular oxygen by
plasticizer substances in optimal concentrations.
2. In the region of the absorbed dozes 40…100 kGy:
- Increase in concentration of "initial" luminescent
additive essentially exceeding concentration of macro-
radicals formed at these dozes;
- Introduction to PS structure of low-molecular com-
binations, which during irradiation easily form radicals
capable to recombination with incipient stable macro-
radicals.
REFERENCES
1. V.K. Milinchuk, E.R. Klinshpont, S.J. Pshezhetsky
Macroradicals. M.: Chemistry, 1980.
2. V.B. Taraban, I.P. Shelukhov, G.S. Zhdanov,
N.I. Voronkina. The role of macroradicals in the
decreasing of the plastic scintillators radiation resis-
tance // Radiat. Phys. Chem. 1995, v.46, №4-6,
p.1321-1324.
3. N.I. Voronkina, O.A. Gunder, G.S. Zhdanov,
V.K. Milinchuk. Radiation and photoradiation pros-
esses in methyl derivatives of polystyrene and in
scintillation compositions based on them // Func-
tional materials. 1994, v.1, №1, p.118-127.
4. J.B. Berlman. Handbook of Fluorescence Spectra
of Aromatic Molecules. N.Y.: “Acad. Press”, 1965.
ДЕГРАДАЦИЯ РАДИОЛЮМИНЕСЦЕНЦИИ СЦИНТИЛЛЯТОРОВ НА ОСНОВЕ ПОЛИСТИРОЛА
И ПОЛИ-2,4-ДИМЕТИЛСТИРОЛА, СПОСОБЫ ПОВЫШЕНИЯ ИХ РАДИАЦИОННОЙ
СТОЙКОСТИ
Н.И. Воронкина, В.Г. Сенчишин, В.К. Милинчук, И.П. Шелухов
Получены спектры радиолюминесценции пластмассовых сцинтилляторов на основе полистирола и поли-
2,4-диметилстирола при воздействии на них γ-излучения. Показано, что наиболее эффективными тушителя-
ми являются макрорадикалы, на которые происходит перенос энергии возбуждения с первичной люминес-
цирующей добавки. Предложены способы повышения радиационной стойкости ПС.
ДЕГРАДАЦІЯ РАДІОЛЮМІНЕСЦЕНЦІЇ СЦИНТИЛЯТОРІВ НА ОСНОВІ ПОЛІСТИРОЛУ ТА
ПОЛІ-2,4-ДИМЕТИЛСТИРОЛУ, СПОСОБИ ПІДВИЩЕННЯ ЇХ РАДІАЦІЙНОЇ СТІЙКОСТІ
Н.І. Воронкіна, В.Г. Сенчишин, В.К. Мілінчук, І.П. Шелухов
Одержано спектри радіолюмінесценції пластмасових сцинтиляторів на основі полістиролу та полі-2,4-
диметилстиролу під дією γ-випромінювання. Показано, що найбільш ефективними гасниками є
макрорадикали, на які відбувається перенос енергії збудження з первинної люмінесціючої домішки.
Запропоновано способи підвищення радіаційної стійкості ПС.
____________________________________________________________
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2006. № 3.
Series: Nuclear Physics Investigations (47), p. 145-147. 147
ДЕГрадАЦиЯ РАДИолюминесценции сцинтилляторов на основе полистирола и поли-2,4-диметилстирола, способы повышения их радиационной стойкости
ДЕГРАДАЦІЯ радіолюмінесценції сцинтиляторів на основі полістиролу та полі-2,4-диметилстиролу, способи підвищення їх радіаційної стійкості
|
| id | nasplib_isofts_kiev_ua-123456789-79874 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T17:32:29Z |
| publishDate | 2006 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Voronkina, N.I. Senchyshyn, V.G. Milinchuk, V.K. Sheluhov, I.P. 2015-04-06T14:47:03Z 2015-04-06T14:47:03Z 2006 Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing / N.I. Voronkina, V.G. Senchyshyn, V.K. Milinchuk, I.P. Sheluhov // Вопросы атомной науки и техники. — 2006. — № 3. — С. 145-147. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 29.40.Mc https://nasplib.isofts.kiev.ua/handle/123456789/79874 Spectra of radioluminescence of plastic scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene under
 an influence of γ-radiation are obtained. It is shown that the most effective quenchers are macroradicals, on
 which a transmission of excitation energy from “initial” luminescent additives occurs. The ways to increase PS radiating
 stability are proposed. Получены спектры радиолюминесценции пластмассовых сцинтилляторов на основе полистирола и поли-2,4-диметилстирола при воздействии на них γ-излучения. Показано, что наиболее эффективными тушителями являются макрорадикалы, на которые происходит перенос энергии возбуждения с первичной люминесцирующей добавки. Предложены способы повышения радиационной стойкости ПС. Одержано спектри радіолюмінесценції пластмасових сцинтиляторів на основі полістиролу та полі-2,4-
 диметилстиролу під дією γ-випромінювання. Показано, що найбільш ефективними гасниками є
 макрорадикали, на які відбувається перенос енергії збудження з первинної люмінесціючої домішки.
 Запропоновано способи підвищення радіаційної стійкості ПС. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Применение ускорителей в радиационных технологиях Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing Деградация радиолюминесценции сцинтилляторов на основе полистирола и поли-2,4-диметилстирола, способы повышения их радиационной стойкости Деградація радіолюмінесценції сцинтиляторів на основі полістиролу та полі-2,4-диметилстиролу, способи підвищення їх радіаційної стійкості Article published earlier |
| spellingShingle | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing Voronkina, N.I. Senchyshyn, V.G. Milinchuk, V.K. Sheluhov, I.P. Применение ускорителей в радиационных технологиях |
| title | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| title_alt | Деградация радиолюминесценции сцинтилляторов на основе полистирола и поли-2,4-диметилстирола, способы повышения их радиационной стойкости Деградація радіолюмінесценції сцинтиляторів на основі полістиролу та полі-2,4-диметилстиролу, способи підвищення їх радіаційної стійкості |
| title_full | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| title_fullStr | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| title_full_unstemmed | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| title_short | Radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| title_sort | radioluminescence degradation of scintillators on a basis of polystyrene and poly-2,4-dimethylstyrene, the ways of their radiating stability increasing |
| topic | Применение ускорителей в радиационных технологиях |
| topic_facet | Применение ускорителей в радиационных технологиях |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/79874 |
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