Radiation effects in semiconductor scintillators based on zinc selenide
Effects have been studied of gamma-radiation (Еγ=1.25 МeV) in doses of DγЈ5.10⁹ rad upon light output and spectral-kinetic luminescence characteristics of new semiconductor scintillators (SCS) based on isovalently doped (with tellurium and oxygen) zinc selenide crystals. SCS crystals have been shown...
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| Опубліковано в: : | Вопросы атомной науки и техники |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2003
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Radiation effects in semiconductor scintillators based on zinc selenide / V. Ryzhikov, V. Koshkin, N. Starzhinskiy, E. Ibragimova, A. Gafarov, A. Kist, B. Oksengendler, L. Gal’chinetskii, K. Katrunov, S. Galkin, V. Silin // Вопросы атомной науки и техники. — 2003. — № 3. — С. 138-142. — Бібліогр.: 7 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859650533343625216 |
|---|---|
| author | Ryzhikov, V. Koshkin, V. Starzhinskiy, N. Ibragimova, E. Gafarov, A. Kist, A. Oksengendler, B. Gal’chinetskii, L. Katrunov, K. Galkin, S. Silin, V. |
| author_facet | Ryzhikov, V. Koshkin, V. Starzhinskiy, N. Ibragimova, E. Gafarov, A. Kist, A. Oksengendler, B. Gal’chinetskii, L. Katrunov, K. Galkin, S. Silin, V. |
| citation_txt | Radiation effects in semiconductor scintillators based on zinc selenide / V. Ryzhikov, V. Koshkin, N. Starzhinskiy, E. Ibragimova, A. Gafarov, A. Kist, B. Oksengendler, L. Gal’chinetskii, K. Katrunov, S. Galkin, V. Silin // Вопросы атомной науки и техники. — 2003. — № 3. — С. 138-142. — Бібліогр.: 7 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | Effects have been studied of gamma-radiation (Еγ=1.25 МeV) in doses of DγЈ5.10⁹ rad upon light output and spectral-kinetic luminescence characteristics of new semiconductor scintillators (SCS) based on isovalently doped (with tellurium and oxygen) zinc selenide crystals. SCS crystals have been shown to be of extremely high radiation stability, and changes in their optical and luminescent properties became noticeable only under doses Dγ>(7.9).10⁷ rad. Under gamma-irradiation with Dγ>(2-5).10⁹ rad and Pγ=7.7.10² R.s⁻¹, in the surface layer (estimated in tens of nanometers) radiolysis of the crystalline structure occurs, and the loss of mass is observed for the samples (at Т=320 К). Mechanisms are considered that describes variation of SCS properties under powerful radiation fluxes.
Вивчено вплив гамма-випромінення з енергією Еγ=1.25 МеВ і дозами DγЈ5.10⁹ рад а також нейтронів (Еn>0.55 еВ, з них 85% с Еn>3 МеВ) на світловий вихід і спектрально-кінетичні характеристики люмінесценції нових напівпровідникових сцинтиляторів (НПС) на основі ізовалентно легованих (телуром, киснем) кристалів селеніда цинку. Показано, що кристали НПС мають дуже високу радіаційну стійкість, і зміна їх оптичних і люмінесцентних властивостей стає помітним тільки при дозах Dγ>(7…9).10⁷ рад. При дозах гамма-випромінення Dγ>(2…5).10⁹ рад і Pγ=7.7.10² Р.с⁻¹ у поверхневому прошарку, оцінюваному в десятки нм, спостерігаються радіоліз кристалічної структури і втрата маси зразків (при Т=320 К). Розглянуто механізми змін властивостей НПС під дією потужних потоків випромінювань.
Изучено влияние гамма-излучения с энергией Еγ=1.25 МэВ и дозами DγЈ5.10⁹ рад, а также нейтронов (Еn>0.55 эВ, из них 85% с Еn>3МэВ) с флюенсами FnЈ10¹⁹см², на световыход и спектрально-кинетические характеристики люминесценции новых полупроводниковых сцинтилляторов (ППС) на основе изовалентно легированных (теллуром, кислородом) кристаллов селенида цинка. Показано, что кристаллы ППС обладают очень высокой радиационной стойкостью, и изменение их оптических и люминесцентных свойств становится заметным только при дозах Dγ>(7…9).10⁷ рад. При дозах гамма-излучения Dγ>(2…5).10⁹ рад и Pγ=7.7.10² Р.с⁻¹ в поверхностном слое, оцениваемом в десятки нм, наблюдаются радиолиз кристаллической структуры и потеря массы образцов (при Т=320 К). Рассмотрены механизмы изменений свойств ППС под действием мощных потоков излучений.
|
| first_indexed | 2025-12-07T13:32:57Z |
| format | Article |
| fulltext |
УДК 539.1.074.5:546.23’47
RADIATION EFFECTS IN SEMICONDUCTOR SCINTILLATORS BASED ON ZINC
SELENIDE
V. Ryzhikov1, V. Koshkin2, N. Starzhinskiy1, E. Ibragimova3, A. Gafarov3, A. Kist3,
B. Oksengendler3, L. Gal’chinetskii1, K. Katrunov1, S. Galkin1, V. Silin1
1Concern “Institute for Single Crystals” NASU, 60 Lenin Ave., 61001 Kharkov, Ukraine,
2National Technical University “KhPI”, Kharkov, Ukraine
3Institute of Nuclear Physics АSUzb, Tashkent, Uzbekistan
Effects have been studied of gamma-radiation (Еγ=1.25 МeV) in doses of Dγ≤5⋅109 rad upon light output and spectral-kinetic
luminescence characteristics of new semiconductor scintillators (SCS) based on isovalently doped (with tellurium and oxygen)
zinc selenide crystals. SCS crystals have been shown to be of extremely high radiation stability, and changes in their optical and
luminescent properties became noticeable only under doses Dγ>(7-9)⋅107 rad. Under gamma-irradiation with Dγ>(2-5)⋅109 rad and
Pγ=7.7⋅102 R⋅s-1, in the surface layer (estimated in tens of nanometers) radiolysis of the crystalline structure occurs, and the loss of
mass is observed for the samples (at Т=320 К). Mechanisms are considered that describes variation of SCS properties under pow-
erful radiation fluxes.
1. INTRODUCTION
Interest in studying A2B6 compound based crystals
has increased lately because of their promising applica-
tion as scintillation detectors with some characteristics
being superior to the existing ones [1]. Development of
new types of semiconductor scintillators on the basis of
isovalently doped zinc selenide crystals has allowed to
efficiently broaden the rather short list of scintillators
used in low-energy (E<100 keV) X-ray technical in-
troscopy and medical tomography. As distinct from
crystals CsI(Tl), which are the most widely used for
these purposes, scintillators based on ZnSe(Te,O) crys-
tals are not hygroscopic, their light output is 1.1 to 1.5
times higher, and afterglow level after 10 ms is by 2 to 3
orders of magnitude lower with respect to CsI(Tl) [1,3-
5]. Decay time (3-10 µs) and density (5.42 g.cm-3) of
these new scintillators are quite acceptable for their use
in detectors for X-ray introscopy; their radiation stabili-
ty is not worse, and light output is 2.5-4 times higher
than with crystals CdWO4, Bi4Ge3O12, Gd2SiO5 used for
similar purposes. The radiation stability of the common-
ly used CsI(Tl) crystals is rather low – already under
gamma-radiation doses of 103 to 104 rad their scintilla-
tion properties are significantly deteriorated. At the
same time, according to our preliminary data, output
characteristics of ZnSe(Te,O)-based semiconductor
scintillators (SCS) remain essentially unchanged under
much higher dose loads [1, 4]. In the present work, new
data are presented on the effects of high doses of ioniz-
ing radiation (gamma, neutrons) upon luminescent and
optical characteristics of scintillators based on zinc se-
lenide.
2. SAMPLES AND EXPERIMENTAL
PROCEDURE
Isovalently doped zinc selenide crystals were grown
in graphite crucibles by Bridgman-Stockbarger method
in vertical compression furnaces under argon pressure 5⋅
106 Pa. Growth rate was 2 to 5 mm/hour, and the tem-
perature in the crystallization zone was ~1850 K. As
initial raw material, we used polycrystalline zinc se-
lenide of 5N offered by ELMA Inc. Concentration of
activator dopants was 0.01 to 0.5 wt. %. The main im-
purity in the grown crystals was carbon (from the
growth crucibles), concentration of which was 0.1 to
0.3 wt. %. Three series of ZnSe(Te) crystals have been
studied: i) A series - the appropriate mixture of ZnSe
and ZnTe powders (with 0.5 mass % Te) was treated in
reducing atmosphere before growing crystals, the sam-
ples are labeled AN; ii) B series – crystals of ZnSe with
~0.1 wt. % Te were subjected to treatment in oxygen
containing atmosphere by the method described in [5],
labeled BN; iii) C series - crystals of ZnSe with <0.03
wt. % Te were treated in oxygen (like B), labeled CN
[5]. At the final stage of formation of scintillation prop-
erties, one half from each series of crystals was an-
nealed in Zn vapor (24 hours, 1290 K). The samples are
labeled AT, BT and CT. Further only this type of sam-
ples will be referred to as “SCS”, to distinguish them
from the as-grown (not annealed in Zn vapor)
ZnSe(Te,O) crystals. All samples used in our experi-
ments were of dimensions 10×10×5 mm3.
Gamma-irradiation of the samples was carried out in
evacuated tubes using a channel type 60Co installation at
exposure dose rates Pγ up to 103 R⋅s-1 (the average ener-
gy of gamma-quanta Eγ≈1.25 MeV, the absorbed dose
Dγ≤5⋅109 rad). Under irradiation of all these types, the
temperature of the samples did not exceed 360 K. X-ray
luminescence (XL) of semiconductor scintillator sam-
ples was measured under excitation using an IRIS-3 X-
ray source (Ua=35 kV, ia≤35 mA, Cu anticathode). Con-
centration of activator Te in the crystals was determined
by X-ray luminescence analysis, concentration of oxy-
gen – by the neutron activation method using nuclear re-
action 16O(n,p)16N.
__________________________________________________________________________________
138 ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2003. № 3.
Сеория: Физика радиационных повреждений и радиационное материаловедение (83), с. 138-142.
3. RESULTS AND DISCUSSION
At first all samples were weighed and studied by the
method of X-ray-element analysis. The determined
values were the absolute content of Te and O in
wt. %, the content of Zn and Se in arbitrary units, as
well as Se/Zn ratio. At the ideal stoichiometric
composition of ZnSe (atom ratio Se/Zn=1) the crystals
contain 54,7 wt. %=4.17⋅1021 cm-3 of Se and
45,3 wt. %=4.17⋅1021 cm-3 of Zn. Table 1 shows the
experimental data on composition of AN, AT, BN, BT,
CN, CT series of ZnSe(Te,O) crystals.
Table 1
Composition, stoichiometry and luminescent characteristics of ZnSe(Te,O) crystals at 300 K. Light output
of XL IXL (measured by Si-PD) is normalized to CsJTl IXL=1, and all the intensities of GL (PM) IGL are nor-
malized to that of the reference sample CN3
Samples from AN and AT series has about 0.25-0.5 wt. % Te. The actual content of Te in BN and BT samples
was ~0.18 wt. %, and that in CN and CT samples was about 0.01 wt %. Besides, all samples turned out to be non-
stoichiometric: 49 mass % Se to 51 mass % Zn, which means 3.75⋅1021 cm-3 Se atoms to 4.68×1021 cm-3 Zn atoms.
Thus, the surplus of Zn atoms (or the number of VSe) was found to be ~0.9⋅1021 cm-3 in samples both untreated and
treated in Zn vapor, slightly depending on Te content. However, measuring the Zn profile could give a higher con-
centration of Zn in bulk and near the surface of the treated samples (series T). The stoichiometry deviations in A2B6
crystals, determining the presence of pre-radiation defects are affecting significantly the radiation stability [6].
It is well seen from the Table that the light output of T-series samples (treated in Zn vapor) is higher than in N-
series (untreated), as it should be expected [1]. The treatment in Zn vapor was found to decrease the number of sin-
gle Zn vacancies, unless they were trapped at Te sites to form stable luminescent centers responsible for high light
output of XL at 635-640 nm. Luminescent centers containing oxygen impurity in B and C series of samples are re-
sponsible for another band peaked at 600-610 nm.
Spectral composition of gamma-luminescence (GL) induced by steady 60Co-gamma-irradiation of ZnSe(Te,O) at
the dose rate of 7.7⋅10 R⋅s-1 at 77 and 300 K was studied using the set-up including a light guide and monochromator
SPM2 with photomultiplier (PM). The accumulated gamma-dose after the first scanning of GL spectrum at 77 K
was 3⋅105 rad, and 106 rad after the second scanning at 300 K (shown in figures 1-4,a). Spectra of GL were taken at
77 and 300 K after prolonged irradiation of the samples to high gamma-doses of <109 rad and washing out the
radiolysis products (shown in figures 1-4, b). For a better comparison all GL measurements were carried out at the
same conditions (slit width and amplification degree)
and normalized to the intensity of GL at 300 K IGL=1. It should be noted that the monochromator was 5 m apart from
the samples under the gamma-source, so the actual intensity of GL was much higher. No correction was done for
spectral sensitivity of PM, since the aim of this study was to compare impurity and dose effects on intensity and
wavelength of GL. Both the figures and Table 1 demonstrate clearly these effects.
Sample
[Te],
wt. %
[O],
wt.%
Se/Zn
ratio
IXL,
a.u.
XL,
λmax,
nm
GL,
λmax,,
nm
IGL, at
106 rad,
a.u.
λmax, at
109rad,
nm
IGL, at
109 rad,
a.u.
AN8 0.26 0.014 0.852 0.1 640 640 0.3 490 0.8
AN9 0.57 0.011 0.854 0.34 640 690 0.4 720 1
BN6 0.18 0.021 0.851 0.26 630 650 1.3 680 2.8
CN3 <0.01 0.029 0.861 0.16 610 620 1 - -
CN5 <0.01 0.027 0.849 0.27 610 620 1 660 2
AT5 0.28 0.012 0.836 0.64 635 640 2.6 660 2.6
AT7 0.49 0.014 0.838 0.69 635 640 4.5 670 1.8
BT12 0.19 0.020 0.843 0.47 625 630 2.6 670 1.1
CT5 0.008 0.026 0.841 0.43 600 610 1.8 690 1.4
CT8 0.009 0.028 0.845 0.41 600 610 1.6 690 1.3
139
Fig. 1. Gamma-luminescence of ZnSe(Te,O) crystals (as-grown; 1 – CN5, 2 – CN3, 3 – BN6, 4 – AN9, 5 – AN8)
at 77 K and different doses (a – 105 rad, b – 109 rad). Reference sample CN 3 was not irradiated to 109 rad. Char-
acteristics of the labeled samples are shown in Table 1
Comparison of XL and GL spectra at 300 K (see Table 1 and Figs. 2 and 4) shows that the wavelength of the GL
band maximum λmax is shifted to the “red” side. This is because XL is excited in the thin subsurface ZnSe(Te,O)-
ZnO layer, and GL – in the whole bulk mostly untreated and having just the intrinsic defects.
In all samples irradiated to the high gamma-dose
Fig. 2. GL of ZnSe(Te,O) crystals (as-grown; 1 – CN5, 2 – CN3, 3 – BN6, 4 – AN9, 5 – AN8) at 300 K (a – 106
rad, b – 109 rad). Reference CN3 was not irradiated to 109 rad
(2-5)⋅109 rad (Figures 1-4, b) the spectra of GL at 77
and 300 K changed both in wavelength and intensity. The intensity of GL at 77 K decreased by about 2-3 times,
except the bands at 480 and 530 nm, which remained unchanged (Fig. 1, b and Fig. 3, b).
140
Fig. 3. GL of SCS crystals (treated in Zn vapor; 1 – CT8, 2 – BT12, 3 – AT7, 4 – AT5) at 77 K (a – 105 rad, b –
109 rad)
As expected, the intensity of GL at 300 K decreased by two times only for 2 samples - AT7 and BT12, while
AT5 and CT8 remained unchanged (Fig. 4, b). It should be pointed out that in AN8 sample containing 0.26 % Te the
weak band at 650 nm vanished, and a new much more intense band appeared at 470-490 nm. In the rest of the
studied samples of N series the intensity of GL at 300 K even increased by 2 times (Fig. 2, b). Defect centers of
different energies have been generated under irradiation at 300 K, and the as-grown centers have been destroyed.
The number of the deepest centers containing Te (mostly in A series of samples) was unchanged or decreased to a
lesser extent than those related to oxygen (in B and C series). The long irradiation seemed to destroy the impurity
defect complexes and to create both shallow recombination centers (480 nm) and deep centers (red bands). Then the
red luminescence at 670-720 nm can be attributed to recombination at the radiation-induced isolated VZn in the
presence of Te in A and B series or O in B and C series of crystals [1,2,5]. Then the green-yellow bands at 500-
600 nm can be ascribed to isolated O impurity defects.
Fig. 4. GL of SCS crystals at 300 K (1 – CT8, 2 – BT12, 3 – AT7, 4, 4’ – AT5; a – 106 rad, b – 109 rad)
The product of radiolysis of the surface layer after gamma-irradiation to 109 rad at 300 K was studied by the X-
ray-analysis: the amount of the product and the depth of the removed layer were estimated quantitatively. The total
141
activity of the layer washed out from the surface of all 8 samples (160 mm2) was 1.6⋅10-5 g for Zn isotopes and 1.35⋅
10-5 g for Se isotopes, which made 10-7 g/mm2. The composition of the radiolytic product was found to be the same
as that for the non-irradiated samples. Taking into account the density of ZnSe matrix [1], the depth of the damaged
and removed layer was about 5-20 nm. It should be mentioned that the most obvious part of the radiation damage
occurred at the edges and corners of a sample bar, because they change color (become reddish) and become
smoothened.
Gamma-irradiation to a moderate dose (5-8)⋅107 rad alone caused neither a noticeable radiolysis nor optical
changes. Neutron-irradiation (Fn<1015 cm-2) results only in 10-40 % increasing of the light output [4]. A higher dose
(~2×109 rad) caused more damage of the subsurface layer. The zinc mass loss turned out to be larger than that of se-
lenium, and the absorption edge and the luminescence band shifted toward longer wavelengths. Radiation induced
adsorption of oxygen followed by formation of ZnO micro-inclusions in the sub-surface layer is suggested for ex-
plaining the observed radiolysis effects and changes in the optical spectra and luminescence kinetics. The recombi-
nation luminescence under gamma-irradiation at different temperatures will be discussed below as a competing fac-
tor for the radiolysis (the more intense GL is, the less effective the radiolysis and the higher the radiation hardness
should be).
Among several experimental facts obtained here the observation of extremely high radiation stability of SCS and
radiolysis products after the high gamma-dose of 109 rad seems to be the most interesting. Theoretical description of
high radiation hardness of isovalently doped and nonstoichiometric A2B6 crystals at low irradiation dose rates was
carried out in [6]. For high dose rates, since the radiation-induced damage occurs in a thin subsurface layer of about
5-10 nm, the following model is suggested. The gamma-irradiation produces defects in the whole bulk of samples
by means of ionization. The ionization is a source of elastic shock waves, and the waves become a source of the sur-
face damage. In this model all edges and corners of a sample bar must be damaged more effectively, what indeed
occurs in the experiment. Such a factor of the surface damage under a high dose gamma-irradiation is considered be-
low
Ek
(1) > Ek
(2) > Ek
(3) ; El
(1) > El
(2) > El
(3), Em
(1) > Em
(2) > Em
(3).
Let us select the types of atoms in the spheres in such a way that
Ek
(1) - El
(1) ≥ 3Ek
(2); Ek
(2) - El
(2) ≥ 3Ek
(3) ; Ek
(3) - El
(3) ≥ 3Ek
(4).
Since the ionization cross-section for a high energy Auger-electron (E) has the maximum at E ≥ 3Ei, the primary
ionization of k-shell of the central heavy atom will cause a specific picture of Auger-cascade evolution in the onion-
like structure having such a hierarchy.
Indeed, the Auger-electron of the central atom, emitted with the energy
Ek-l
(1) = Ek
(1) – El
(1),
causes the ionization of k-shell of an atom of the second layer with the probability w2 = l2σ2N2. Auger decay of the
generated hole in the second layer produces a fast electron with the energy
Ek-l
(2) = Ek
(2) – El
(2)
and the probability w3 = l3σ3N3 etc, where li is the thickness of the i-layer of the “onion”, Ni – concentration of i-type
atoms in i-layer, σ3 – cross-section of k-ionization in i-layer. As a result, k-holes are produced in all layers of the
onion structure, each of them creating its own “Coulomb explosion” with the probability αA
i ηi, where ηi – probabil-
ity of ion channel of relaxation of multi-charge state in i-layer after Auger-cascade, and the whole structure releases
a large energy for very short time τtot =∑τi (from i to n) Eexp = Ek
(1) – ∑ Ek-l
(1).
The probability (or cross-section) of the considered process is
∏∏
==
==
n
i
iktot
n
i
itot WWW
2
)1(
1
, , σσ
where n is the number of layers of the “onion”, Wi(σi) – probability (cross-section) of ionization of k-hole in the cen-
tral atom.
142
An energy density released in the “onion” is
3
1
)1(
−
=
=Λ ∑
n
i
ik lE . If to accept li=lo, the cross-section of the pro-
cess exerting the energy Eexp will be
3
1
1
3
1
)1(
1)1(
1)1(
~)(
)()(
n
n
n
kn
ook
n
oooktot
nEN
lNE
−
−
−
−
−
Λ
Λ
=
==
σσ
σσσ
.
Thus, σtot(E) decreases with increasing the density of the exerted energy.
For the case of Auger-cascade in an isolated heavy atom the density of the exerted energy is estimated as
.10
30
1
1
1
)1(
1
−
−
=
≈Ω
−=Λ ∑ AeVEE
n
i
Auger
k
Here ∑
=
n
i
AugerE
1
1 - the sum of kinetic energies of all Auger-electrons in the atom where the Auger cascade devel-
ops: Ω - the atomic volume. Then for “onion” structure of 3 layers the exerted energy density is
( ) 1
3
33/1)1(
2 10003 Λ> >≥Ω=Λ
−
− o
k AeVE .
Obviously, the destruction effect in the both cases is quite different. It is caused both by the Coulomb explosion
inside the “onion” and structure damage in its environment by means of shock waves. The shock wave exerts the
pressure on the front ( ) 6/55/6)1(~ tEP k , where t is the time passed since the moment of exerting energy in the
“onion”. This effect can be initiated both
by external influence and k-capture in the central atom.
Thus, in ZnSe and especially ZnSe(Te,O) crystals intensive gamma-irradiation generates quite powerful shock
waves. On reaching the surface of crystals, these waves can destroy it. The estimations show, that the condition,
when the pressure of the shock waves P is larger than the Young modulus E, can be realized at rather large radius r,
which confirms the suggested model.
4. CONCLUSION
Scintillators based on ZnSe(Te,O) crystals have high radiation stability, preserving satisfactory output character-
istics up to gamma -irradiation doses of Dγ=1⋅108 rad. High dose (>109 R) gamma-irradiation induces elastic shock
waves causing heavy lattice damage and radiolysis of ~10-20 nm subsurface layer.
Accounting for their high light output and low afterglow level, SCS are now the most suitable choice of scintilla-
tor material for modern X-ray introscopic systems and tomographs, as well as dosimeters for detection of power X-
ray and gamma-radiation fluxes.
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2.N.K. Morozova, I.A. Karetnikov, E.M. Gavrischuk. Role of oxygen in forming of deep centers of luminescence in
ZnSe //Inorganic Materials. 1999, v. 35, N 8, p. 917–922.
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tegrated Scintielectronic Radiation Detectors Based thereon //IEEE Trans. Nucl. Sci. 2001, v. 48, N 3, p.356–359.
4.V. Ryzhikov, N. Starzhinskiy, L. Gal'chinetskii et al. Behavior of new ZnSe(Te,O) semiconductor scintillators un-
der high doses of ionizing radiation //IEEE Trans. Nucl. Sci. 2001, v. 48, N 4, p.1561–1564.
5.V.D. Ryzhikov, N.G. Starzhinskiy, L.P. Gal'chinetskii et al. The role of oxygen in formation of radiative recom-
bination centers in ZnSe1-xTex crystals //Int. J. Inorg. Mat., 2001, N 3, p.1227–1229.
6.V.M. Koshkin, I.V. Sinelnic, V.D. Ryzhikov, L.P. Gal’chinetskii, N.G. Starzhinskiy. Comparative analisis of ra-
diation-induced defect accumulation in A2B6 semiconductors //Functional Materials. 2001, v. 8, N 4, p. 592–599.
7.B.A. Arapov, A.B. Avilov, B.L. Oksengendler, A.A. Kim //Izvestiya VUZov, Series of Physics. 2000, v.1, p. 98–
104.
РАДІАЦІЙНІ ЕФЕКТИ У НАПІВПРОВІДНИКОВИХ СЦИНТИЛЯТОРАХ НА ОСНОВІ СЕЛЕНІДУ
ЦИНКУ
143
В.Д. Рижиков, В.М. Кошкін, М.Г. Старжинський, Е.М. Ибрагимова, А.А. Гафаров,
Л.П. Гальчинецький, К.О. Катрунов, В.І. Сілін
Вивчено вплив гамма-випромінення з енергією Еγ =1.25 МеВ і дозами Dγ≤5⋅109 рад а також нейтронів (Еn>0.55 еВ, з
них 85% с Еn>3 МеВ) на світловий вихід і спектрально-кінетичні характеристики люмінесценції нових
напівпровідникових сцинтиляторів (НПС) на основі ізовалентно легованих (телуром, киснем) кристалів селеніда цинку.
Показано, що кристали НПС мають дуже високу радіаційну стійкість, і зміна їх оптичних і люмінесцентних
властивостей стає помітним тільки при дозах Dγ>(7…9)⋅107 рад. При дозах гамма-випромінення Dγ>(2…5)⋅109 рад і Pγ
=7.7⋅102 Р⋅с-1 у поверхневому прошарку, оцінюваному в десятки нм, спостерігаються радіоліз кристалічної структури і
втрата маси зразків (при Т=320 К). Розглянуто механізми змін властивостей НПС під дією потужних потоків
випромінювань.
РАДИАЦИОННЫЕ ЭФФЕКТЫ В ПОЛУПРОВОДНИКОВЫХ СЦИНТИЛЛЯТОРАХ НА ОСНОВЕ
СЕЛЕНИДА ЦИНКА
В.Д. Рыжиков, В.М. Кошкин, Н.Г. Старжинский, Э.М. Ибрагимова, А.А. Гафаров,
Л.П. Гальчинецкий, К.А. Катрунов, В.И. Силин
Изучено влияние гамма-излучения с энергией Еγ=1.25 МэВ и дозами Dγ≤5⋅109 рад, а также нейтронов (Еn>0.55 эВ, из
них 85% с Еn>3МэВ) с флюенсами Fn≤1019см2, на световыход и спектрально-кинетические характеристики люминесцен-
ции новых полупроводниковых сцинтилляторов (ППС) на основе изовалентно легированных (теллуром, кислородом)
кристаллов селенида цинка. Показано, что кристаллы ППС обладают очень высокой радиационной стойкостью, и изме-
нение их оптических и люминесцентных свойств становится заметным только при дозах Dγ>(7…9)⋅107 рад. При дозах
гамма-излучения Dγ>(2…5)⋅109 рад и Pγ=7.7⋅102 Р⋅с-1 в поверхностном слое, оцениваемом в десятки нм, наблюдаются ра-
диолиз кристаллической структуры и потеря массы образцов (при Т=320 К). Рассмотрены механизмы изменений
свойств ППС под действием мощных потоков излучений.
144
CT5
CT8
1. Introduction
Interest in studying A2B6 compound based crystals has increased lately because of their promising application as scintillation detectors with some characteristics being superior to the existing ones [1]. Development of new types of semiconductor scintillators on the basis of isovalently doped zinc selenide crystals has allowed to efficiently broaden the rather short list of scintillators used in low-energy (E<100 keV) X-ray technical introscopy and medical tomography. As distinct from crystals CsI(Tl), which are the most widely used for these purposes, scintillators based on ZnSe(Te,O) crystals are not hygroscopic, their light output is 1.1 to 1.5 times higher, and afterglow level after 10 ms is by 2 to 3 orders of magnitude lower with respect to CsI(Tl) [1,3-5]. Decay time (3-10 s) and density (5.42 g.cm-3) of these new scintillators are quite acceptable for their use in detectors for X-ray introscopy; their radiation stability is not worse, and light output is 2.5-4 times higher than with crystals CdWO4, Bi4Ge3O12, Gd2SiO5 used for similar purposes. The radiation stability of the commonly used CsI(Tl) crystals is rather low – already under gamma-radiation doses of 103 to 104 rad their scintillation properties are significantly deteriorated. At the same time, according to our preliminary data, output characteristics of ZnSe(Te,O)-based semiconductor scintillators (SCS) remain essentially unchanged under much higher dose loads [1, 4]. In the present work, new data are presented on the effects of high doses of ionizing radiation (gamma, neutrons) upon luminescent and optical characteristics of scintillators based on zinc selenide.
2. Samples and experimental procedure
3. Results and discussion
Let us select the types of atoms in the spheres in such a way that
Indeed, the Auger-electron of the central atom, emitted with the energy
The probability (or cross-section) of the considered process is
References
|
| id | nasplib_isofts_kiev_ua-123456789-110930 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T13:32:57Z |
| publishDate | 2003 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Ryzhikov, V. Koshkin, V. Starzhinskiy, N. Ibragimova, E. Gafarov, A. Kist, A. Oksengendler, B. Gal’chinetskii, L. Katrunov, K. Galkin, S. Silin, V. 2017-01-07T08:24:04Z 2017-01-07T08:24:04Z 2003 Radiation effects in semiconductor scintillators based on zinc selenide / V. Ryzhikov, V. Koshkin, N. Starzhinskiy, E. Ibragimova, A. Gafarov, A. Kist, B. Oksengendler, L. Gal’chinetskii, K. Katrunov, S. Galkin, V. Silin // Вопросы атомной науки и техники. — 2003. — № 3. — С. 138-142. — Бібліогр.: 7 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/110930 539.1.074.5:546.23’47 Effects have been studied of gamma-radiation (Еγ=1.25 МeV) in doses of DγЈ5.10⁹ rad upon light output and spectral-kinetic luminescence characteristics of new semiconductor scintillators (SCS) based on isovalently doped (with tellurium and oxygen) zinc selenide crystals. SCS crystals have been shown to be of extremely high radiation stability, and changes in their optical and luminescent properties became noticeable only under doses Dγ>(7.9).10⁷ rad. Under gamma-irradiation with Dγ>(2-5).10⁹ rad and Pγ=7.7.10² R.s⁻¹, in the surface layer (estimated in tens of nanometers) radiolysis of the crystalline structure occurs, and the loss of mass is observed for the samples (at Т=320 К). Mechanisms are considered that describes variation of SCS properties under powerful radiation fluxes. Вивчено вплив гамма-випромінення з енергією Еγ=1.25 МеВ і дозами DγЈ5.10⁹ рад а також нейтронів (Еn>0.55 еВ, з них 85% с Еn>3 МеВ) на світловий вихід і спектрально-кінетичні характеристики люмінесценції нових напівпровідникових сцинтиляторів (НПС) на основі ізовалентно легованих (телуром, киснем) кристалів селеніда цинку. Показано, що кристали НПС мають дуже високу радіаційну стійкість, і зміна їх оптичних і люмінесцентних властивостей стає помітним тільки при дозах Dγ>(7…9).10⁷ рад. При дозах гамма-випромінення Dγ>(2…5).10⁹ рад і Pγ=7.7.10² Р.с⁻¹ у поверхневому прошарку, оцінюваному в десятки нм, спостерігаються радіоліз кристалічної структури і втрата маси зразків (при Т=320 К). Розглянуто механізми змін властивостей НПС під дією потужних потоків випромінювань. Изучено влияние гамма-излучения с энергией Еγ=1.25 МэВ и дозами DγЈ5.10⁹ рад, а также нейтронов (Еn>0.55 эВ, из них 85% с Еn>3МэВ) с флюенсами FnЈ10¹⁹см², на световыход и спектрально-кинетические характеристики люминесценции новых полупроводниковых сцинтилляторов (ППС) на основе изовалентно легированных (теллуром, кислородом) кристаллов селенида цинка. Показано, что кристаллы ППС обладают очень высокой радиационной стойкостью, и изменение их оптических и люминесцентных свойств становится заметным только при дозах Dγ>(7…9).10⁷ рад. При дозах гамма-излучения Dγ>(2…5).10⁹ рад и Pγ=7.7.10² Р.с⁻¹ в поверхностном слое, оцениваемом в десятки нм, наблюдаются радиолиз кристаллической структуры и потеря массы образцов (при Т=320 К). Рассмотрены механизмы изменений свойств ППС под действием мощных потоков излучений. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Физика радиационных и ионно-плазменных технологий Radiation effects in semiconductor scintillators based on zinc selenide Радіаційні ефекти у напівпровідникових сцинтиляторах на основі селеніду цинку Радиационные эффекты в полупроводниковых сцинтилляторах на основе селенида цинка Article published earlier |
| spellingShingle | Radiation effects in semiconductor scintillators based on zinc selenide Ryzhikov, V. Koshkin, V. Starzhinskiy, N. Ibragimova, E. Gafarov, A. Kist, A. Oksengendler, B. Gal’chinetskii, L. Katrunov, K. Galkin, S. Silin, V. Физика радиационных и ионно-плазменных технологий |
| title | Radiation effects in semiconductor scintillators based on zinc selenide |
| title_alt | Радіаційні ефекти у напівпровідникових сцинтиляторах на основі селеніду цинку Радиационные эффекты в полупроводниковых сцинтилляторах на основе селенида цинка |
| title_full | Radiation effects in semiconductor scintillators based on zinc selenide |
| title_fullStr | Radiation effects in semiconductor scintillators based on zinc selenide |
| title_full_unstemmed | Radiation effects in semiconductor scintillators based on zinc selenide |
| title_short | Radiation effects in semiconductor scintillators based on zinc selenide |
| title_sort | radiation effects in semiconductor scintillators based on zinc selenide |
| topic | Физика радиационных и ионно-плазменных технологий |
| topic_facet | Физика радиационных и ионно-плазменных технологий |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/110930 |
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