Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation
The paper examines the possibility of using an organic polycrystal as the “opaque” scintillator. Polycrystals are produced by pressing crystalline grains. When light propagates through a polycrystal, it is repeatedly reflected and refracted at the boundaries of the grains. This makes its propagation...
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| Cite this: | Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation / Ya.I. Polupan, I.V. Lazarev, E.V. Martynenko, S.S. Minenko, O.A. Tarasenko, V.A. Тarasov // Problems of Atomic Science and Technology. — 2023. — № 3. — С. 38-42. — Бібліогр.: 10 назв. — англ. |
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Polupan, Ya.I. Lazarev, I.V. Martynenko, E.V. Minenko, S.S. Tarasenko, O.A. Тarasov, V.A. 2023-12-10T16:48:58Z 2023-12-10T16:48:58Z 2023 Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation / Ya.I. Polupan, I.V. Lazarev, E.V. Martynenko, S.S. Minenko, O.A. Tarasenko, V.A. Тarasov // Problems of Atomic Science and Technology. — 2023. — № 3. — С. 38-42. — Бібліогр.: 10 назв. — англ. 1562-6016 PACS: 32.50.+d; 78.60.−b; 87.53 DOI: https://doi.org/10.46813/2023-145-038 https://nasplib.isofts.kiev.ua/handle/123456789/196135 The paper examines the possibility of using an organic polycrystal as the “opaque” scintillator. Polycrystals are produced by pressing crystalline grains. When light propagates through a polycrystal, it is repeatedly reflected and refracted at the boundaries of the grains. This makes its propagation difficult. We studied the light output and optical transmittance of stilbene and p-terphenyl polycrystals with different fractions of crystalline grain: from 0.06…0.1 to 2.0…2.5 mm (the samples 20 mm in diameter and 2 mm in height) was conducted. Modelling of light propagation in polycrystalline samples of stilbene and p-terphenyl was carried out and the values of the light collection coefficients were calculated. It was found that in order to obtain the polycrystalline samples with sufficiently high light output and high efficiency of detection of local sites of interaction of ionizing radiations, grains in the range of 0.4…0.8 mm should be used. Досліджується можливість використання органічного полікристалa в якості “мутного” сцинтилятора. Полікристали виготовляють методом пресування кристалічних гранул. Світло при розповсюдженні крізь полікристал зазнає багаторазового відбивання та заломлення на границях гранул, що ускладнює його проходження. Проведено дослідження світлового виходу та оптичного пропускання полікристалів стильбену та п-терфенілу із різними фракціями кристалічних гранул: від 0,06…0,1 до 2,0…2,5 мм (діаметр зразків 20 мм та висота 2 мм). Проведено моделювання проходження світла в полікристалічних зразках стильбену та п-терфенілу, та розраховані значення коефіцієнтів світлозбирання в них. З’ясовано, що для отримання полікристалічних зразків із достатньо високим світловим виходом та високою ефективністю виявлення локальних місць взаємодії іонізуючого випромінювання слід використовувати гранули в діапазоні 0,4…0,8 мм. This work was supported by the National Research Foundation of Ukraine, project № 2021.01/0042 “Development of effective detection systems for the most harmful ionizing radiation for humans, for radioecology tasks”. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Problems of Atomic Science and Technology Detectors and nuclear radiation detection Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation Особливості формування сцинтиляційного відгуку в органічних матеріалах із стохастичним характером розповсюдження світла Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| title |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| spellingShingle |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation Polupan, Ya.I. Lazarev, I.V. Martynenko, E.V. Minenko, S.S. Tarasenko, O.A. Тarasov, V.A. Detectors and nuclear radiation detection |
| title_short |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| title_full |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| title_fullStr |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| title_full_unstemmed |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| title_sort |
peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation |
| author |
Polupan, Ya.I. Lazarev, I.V. Martynenko, E.V. Minenko, S.S. Tarasenko, O.A. Тarasov, V.A. |
| author_facet |
Polupan, Ya.I. Lazarev, I.V. Martynenko, E.V. Minenko, S.S. Tarasenko, O.A. Тarasov, V.A. |
| topic |
Detectors and nuclear radiation detection |
| topic_facet |
Detectors and nuclear radiation detection |
| publishDate |
2023 |
| language |
English |
| container_title |
Problems of Atomic Science and Technology |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Особливості формування сцинтиляційного відгуку в органічних матеріалах із стохастичним характером розповсюдження світла |
| description |
The paper examines the possibility of using an organic polycrystal as the “opaque” scintillator. Polycrystals are produced by pressing crystalline grains. When light propagates through a polycrystal, it is repeatedly reflected and refracted at the boundaries of the grains. This makes its propagation difficult. We studied the light output and optical transmittance of stilbene and p-terphenyl polycrystals with different fractions of crystalline grain: from 0.06…0.1 to 2.0…2.5 mm (the samples 20 mm in diameter and 2 mm in height) was conducted. Modelling of light propagation in polycrystalline samples of stilbene and p-terphenyl was carried out and the values of the light collection coefficients were calculated. It was found that in order to obtain the polycrystalline samples with sufficiently high light output and high efficiency of detection of local sites of interaction of ionizing radiations, grains in the range of 0.4…0.8 mm should be used.
Досліджується можливість використання органічного полікристалa в якості “мутного” сцинтилятора. Полікристали виготовляють методом пресування кристалічних гранул. Світло при розповсюдженні крізь полікристал зазнає багаторазового відбивання та заломлення на границях гранул, що ускладнює його проходження. Проведено дослідження світлового виходу та оптичного пропускання полікристалів стильбену та п-терфенілу із різними фракціями кристалічних гранул: від 0,06…0,1 до 2,0…2,5 мм (діаметр зразків 20 мм та висота 2 мм). Проведено моделювання проходження світла в полікристалічних зразках стильбену та п-терфенілу, та розраховані значення коефіцієнтів світлозбирання в них. З’ясовано, що для отримання полікристалічних зразків із достатньо високим світловим виходом та високою ефективністю виявлення локальних місць взаємодії іонізуючого випромінювання слід використовувати гранули в діапазоні 0,4…0,8 мм.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/196135 |
| citation_txt |
Peculiarities of the formation of scincillation response in organic materials with stochastic character of light propagation / Ya.I. Polupan, I.V. Lazarev, E.V. Martynenko, S.S. Minenko, O.A. Tarasenko, V.A. Тarasov // Problems of Atomic Science and Technology. — 2023. — № 3. — С. 38-42. — Бібліогр.: 10 назв. — англ. |
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2025-11-25T08:10:06Z |
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38 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №3(145)
DETECTORS AND NUCLEAR RADIATION DETECTION
https://doi.org/10.46813/2023-145-038
PECULIARITIES OF THE FORMATION OF SCINCILLATION
RESPONSE IN ORGANIC MATERIALS WITH STOCHASTIC
CHARACTER OF LIGHT PROPAGATION
Ya.I. Polupan*, I.V. Lazarev, E.V. Martynenko, S.S. Minenko, O.A. Tarasenko, V.A. Тarasov
Institute for Scintillation Materials NAS of Ukraine, Kharkiv, Ukraine
*E-mail: polupan.yaroslava@gmail.com
The paper examines the possibility of using an organic polycrystal as the "opaque" scintillator. Polycrystals are
produced by pressing crystalline grains. When light propagates through a polycrystal, it is repeatedly reflected and
refracted at the boundaries of the grains. This makes its propagation difficult. We studied the light output and optical
transmittance of stilbene and p-terphenyl polycrystals with different fractions of crystalline grain: from 0.06…0.1 to
2.0…2.5 mm (the samples 20 mm in diameter and 2 mm in height) was conducted. Modelling of light propagation
in polycrystalline samples of stilbene and p-terphenyl was carried out and the values of the light collection
coefficients were calculated. It was found that in order to obtain the polycrystalline samples with sufficiently high
light output and high efficiency of detection of local sites of interaction of ionizing radiations, grains in the range of
0.4…0.8 mm should be used.
PACS: 32.50.+d; 78.60.−b; 87.53
INTRODUCTION
In the vast majority of applied problems, transparent
scintillators are used. Transparency is an important
characteristic of the scintillator, its decrease leads to a
decrease in the intensity of light reaching the
photodetector, that is, to a decrease in the value of the
technical light output. Recently, the idea of using
precisely the scintillators with low transparency
("opaque" scintillators) to localize the local place of
scintillation pulse was arisen [1]. Complicating the
propagation of scintillation light through such an
"opaque" scintillator and the use of lightguides located
at a certain distance from each other in the volume of
the scintillator allow solving this problem. Liquid
scintillators are proposed to be used as "opaque"
scintillation materials [1]. However, liquid scintillators
are known to be inconvenient when used in practice due
to their fire hazard, thermal expansion, leakage hazard,
toxicity, etc.
The use of organic polycrystals as an "opaque"
scintillator, as an alternative to liquid scintillators,
seems promising. Polycrystalline scintillators are made
by pressing crystal grains or plates. Therefore, when
light propagates through a polycrystal, it is repeatedly
reflected and refracted at the boundaries of grains or
plates, that makes its propagation difficult. Note, that
polycrystalline scintillators retain most of the
advantages of singlecrystalline scintillators (high decay
time, high efficiency of detecting short-range and
neutron radiation, the ability to separately detection an
ionizing radiation, etc.), but at the same time have a
significantly lower cost. In addition, polycrystalline
scintillators are quite resistant to the appearance of
cracks during mechanical processing, that allows the
integration of lightguides into their volume. Changing
the conditions for obtaining polycrystals (temperature,
pressure, grain size) allows to vary their scintillation
characteristics (for example, light output), as well as the
degree of their transparency. At the same time, the goal
of previous research was to achieve the maximum
values of light output and transparency of polycrystals.
Determining the conditions for obtaining
polycrystalline scintillators, which are characterized at
the same time by high light output, high uniformity of
light output and a given degree of scattering, is an
urgent task.
1. EXPERIMENTAL
1.1. SAMPLES PREPARATION
To obtain trans-stilbene and p-terphenyl grains,
quasi-crystalline ingots obtained after zone melting of
trans-stilbene and p-terphenyl raw materials were used.
The resulting grains were sifted through calibrated
sieves and divided into fractions. The sizes of the holes
in the calibrated sieves we selected were: 0.06, 0.1, 0.3,
0.5, 1.0, 1.5, 2.0, and 2.5 mm. Samples of
polycrystalline scintillators were made from crystalline
grains by the method of hot pressing [2–5]. Fig. 1
presents the photo of polycrystalline p-terphenyl
scintillators obtained from grains of different fractions.
Fig. 1. Photo of polycrystalline scintillators of p-
terphenyl obtained from grains of different fractions
1.2. EXPERIMENTAL METHODS
The relative light output of polycrystalline
scintillators was determined by the standard method
using scintillation amplitude spectra. The
photomultiplier 9208А (Electron Tubes Ltd.) was used
as a photodetector, which has a dark current of
6.8·10
–11
A at an anode sensitivity of 50 A/Lm [6]. The
amplitude distribution of scintillator pulses was
obtained using an amplitude-to-digital converter. The
ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №3(145) 39
relative value of the light output value was calculated
according to (1):
100 %,
ref
JL
J
(1)
where J is the value of the amplitude that corresponds to
the center of gravity of the peak in the spectrum of the
scintillator under investigation, Jref is the value of the
amplitude that corresponds to the center of gravity of
the peak in the spectrum of the reference scintillator.
Single crystals of stilbene and p-terphenyl were used as
reference scintillators.
We used the following sources of ionizing radiation:
239
Pu (alpha particles with energy Е = 5.15 MeV,
specific energy loss dE/dx 10
3
MeV/cm);
137
Cs
(conversion electrons with energy Еβ = 0.6225 MeV,
specific energy loss dE/dx 10
–1
MeV/cm).
The optical transmittance of the samples was
determined using a Shimadzu UV 2450
spectrophotometer [7] using an integrating sphere.
Measurements were performed in the wavelength range
from 200 to 750 nm. The value of optical transmittance
T was calculated as follows:
0
100 %,LT
L
(2)
where L0 is the flux of light falling on the sample, L is
the flux of light that propagates through the sample. In
fact, the value of T (2) is the relative light transmittance,
where T = 100% is the light transmittance of air at room
temperature.
1.3. MODELLING OF LIGHT PROPAGATION
IN HETEROGENEOUS MATERIAL
Computer modeling of scintillation light propagation
in a heterogeneous medium was used to determine the
light collection coefficients. In the modeling program,
the heterogeneous scintillator is represented as a
dispersed phase and a dispersed medium, i.e., a system
with many boundaries separating two phases with
different physical properties. In a number of works
[8, 9], the heterogeneous scintillator is presented in the
form of densely packed balls with a dispersed medium
that fills the voids (Fig. 2).
Fig. 2. A model of a heterogeneous scintillator in the
form of spheres with dense volume-centered packing
In the geometric model of the heterogeneous
scintillator that we used, its volume is also divided into
simulated cells. Each cell contains a portion of the
dispersed phase of a given shape (with fixed or random
size and location). Such a geometric model allows
obtaining different variants of modeling heterogeneous
scintillators. For the dispersed phase in the form of
spheres, a volume filling factor of 0.52 can be obtained
(dense volume-centered packing). This approach allows
representing systems with a random location in cells of
particles of different or the same size. The approach
used in this work to model the propagation of light in
heterogeneous scintillators was described in [10].
The simulation program uses the Monte Carlo
method. At various stages the specific parameters of the
simulation (locations and directions of radiation,
absorption in the volume and refraction/reflection at the
boundaries of the media, etc.) are randomly selected
("randomized") based on the respective coefficients or
distributions. The MeshTarReflector program was used
for modeling.
2. RESULTS OF INVESTIGATION
AND THEIR ANALYSIS
2.1. LIGHT OUTPUT
The paper investigated the relative light output of
samples of stilbene and p-terphenyl polycrystals
obtained from 7 fractions of crystalline grains of
different sizes, namely: 0.06…0.1, 0.1…0.3, 0.3…0.5,
0.5…1.0, 1.0…1.5, 1.5…2.0, 2.0…2.5 mm. Sample
thickness h = 2 mm, diameter d = 20 mm.
Corresponding single crystals with a thickness of
h = 5 mm and a diameter of d = 30 mm were used as
reference detectors.
As an example, Fig. 3 presents the results of
calculations of the relative light output of stilbene
polycrystals with different sizes of crystal grains under
alpha excitation, and Fig. 4 presents the results of
calculations of the relative light output of p-terphenyl
polycrystals with different sizes of crystal grains upon
excitation by conversion electrons.
Fig. 3. Relative light output L of stilbene polycrystals
with different sizes of crystal grains under alpha
excitation
Fig. 4. Relative light output L of p-terphenyl
polycrystals with different sizes of crystal grains upon
excitation by conversion electrons
40 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №3(145)
2.2. OPTICAL TRANSMITTANCE OF SAMPLES
Figs. 5 and 6 present the dependences of optical
transmittance T of a series of polycrystals of stilbene
and p-terphenyl, respectively, on the average size of
crystalline grains Lav. The T-values are given for the
luminescence wavelength ( = 400 nm) and for the
scintillator transparency region ( = 700 nm).
Fig. 5. The value of the optical transmittance T
of stilbene polycrystals at the wavelength of
luminescence ( = 400 nm) and in the region
of transparency ( = 700 nm)
Fig. 6. The value of the optical transmittance T
of p-terphenyl polycrystals at the wavelength
of luminescence ( = 400 nm) and in the region
of transparency ( = 700 nm)
2.3. RESULTS OF SIMULATION OF LIGHT
PROPAGATION IN POLYCRYSTALLINE
SAMPLES OF STILBENE AND P-TERPHENYL
SCINTILLATORS
The propagation of light in polycrystalline samples
of stilbene and p-terphenyl scintillators obtained by the
hot pressing method was simulated. Both the size of the
samples with a diameter of 20 mm and a height of
2 mm, and the size of the grains were specified. It was
assumed that in the process of pressing, the sizes of the
initial scintillator grains change slightly, except for the
largest ones. For the size series of the original real
grains 2.25, 1.75, 1.25, 0.75, 0.4, 0.2, and 0.08 mm,
practically the same series of virtual cells was used:
22.5, 1.75, 1.25, 0.75, and 0.4 mm. The "gap"
(boundary layer) between the particles was set to
0.01 mm. Refractive indices and light absorption
coefficients for the scintillator and boundary layer were
also specified. An external reflector was not used during
the simulation.
Fig. 7. Light propagation in a heterostructured
scintillator with a grain size of 2 mm
During the operation of the program, the trajectories
(lines) or the places of changes in the trajectories
(points) of the rays were displayed. Screenshots of
examples of displaying the places of changes in the
trajectories (points) of the rays are shown in Figs. 7–9.
Fig. 8. Light propagation in a heterostructured
scintillator with a grain size of 0.75 mm
Fig. 9. Light propagation in a heterostructured
scintillator with a grain size of 0.4 mm
It can be seen that the positions of the points
demonstrate the structure of the model object, that is,
the places of refraction/reflection at the phase
boundaries. The results of calculations of light
collection coefficients are given in Table.
In all cases the light collection coefficient decreases
with decreasing a grain size, which is explained by an
increase in the number of reflections/refractions and the
path length.
ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №3(145) 41
The value of light collection coefficients
of polycrystalline samples
Average
grain size,
mm
Light collection coefficients
Stilbene p-Terphenyl
Alpha Electrons Alpha Electrons
0.08 0.191 0.315 0.117 0.303
0.2 0.239 0.379 0.183 0.366
0.4 0.280 0.433 0.231 0.436
0.75 0.281 0.445 0.276 0.445
1.25 0.327 0.514 0.282 0.510
1.75 0.389 0.597 0.324 0.594
2.25 0.379 0.602 0.383 0.597
This increases the probability of absorption in the
volume or exiting the volume boundaries. When
modeling the propagation of light from alpha particles
(the emergence of light in the surface layer of 0.35 μm),
the light collection coefficients are smaller than in the
case of internal conversion electrons (the range in the
considered substances is more than 2 mm). In the latter
case, the average path of the rays to the output window
of the photodetector will be smaller than in the first
case. The corresponding light collection coefficients for
stilbene and p-terphenyl are approximately the same,
which is consistent with experimental measurements of
the optical transmittance of the samples and the relative
light output. This correspondence also indicates the
main role of the light collection process in the formation
of the light signal at the output of the scintillator.
2.4. ANALYSIS OF THE EXPERIMENTAL
RESULTS
We analyzed the above experimental results,
namely, 1) the results of measuring the relative light
output of samples of stilbene and p-terphenyl
polycrystals obtained from 7 fractions of crystalline
grains of different sizes, namely: 0.06…0.1, 0.1…0.3,
0.3…0.5, 0.5…1.0, 1.0…1.5, 1.5…2.0, and
2.0…2.5 mm; 2 ) the results of the study of the optical
transmittance values T of the above-mentioned
polycrystal samples, and 3) the results of the
calculations of the light collection coefficients for
these samples. The results of this analysis are combined
in Figs. 10–13, where the normalized values of the
relative light output L, optical transmittance T, and light
collection coefficients are presented as a function of
the average size Lav of grains of these polycrystalline
samples. Each of these parameters is obtained by
normalization to its maximum values obtained in
separate calculations. This made it possible to visually
combine the values of various parameters in one figure.
Figs. 10 and 11 combine the results of calculations
of light collection coefficients , transmittance T and
relative light output L for stilbene polycrystals,
respectively, upon excitation by
239
Pu alpha particles
and conversion electrons of the
137
Cs source. Of course,
the value of optical transmittance T (at a wavelength of
= 400 nm) is the same as in Figs. 10 and 11. Figs. 12
and 13 present similar normalized values of light
collection coefficients , transmittance T and relative
light output L for p-terphenyl polycrystals.
Fig. 10. Normalized values of light collection coefficient
, optical transmittance T ( = 400 nm) and relative
light output L for stilbene polycrystals excited by alpha
particles of
239
Pu
Fig. 11. Normalized values of light collection coefficient
, optical transmittance T ( = 400 nm)
and relative light output L for stilbene polycrystals
excited by conversion electrons of
137
Cs
Fig. 12. Normalized values of light collection coefficient
, optical transmittance T ( = 400 nm)
and relative light output L for p-terphenyl polycrystals
excited by alpha particles of
239
Pu
On the one hand, the scintillation a detector must
have a sufficiently high light output and a sufficiently
high transparency. But on the other hand, for its
possible use as an "opaque" scintillation detector for
effective detection of local interaction sites of ionizing
radiations, its transparency and propagation of
scintillation photons should be sufficiently limited. The
analysis of the data presented above (see Figs. 10–13)
shows that polycrystalline samples obtained from
fractions of grains 0.06…0.1 and 0.1…0.3 mm have
extremely low values of the of light collection
coefficients , transmittance T ( = 400 nm) and the
relative light output L.
42 ISSN 1562-6016. Problems of Atomic Science and Technology. 2023. №3(145)
Fig. 13. Normalized values of light collection coefficient
, optical transmittance T ( = 400 nm) and relative
light output L for p-terphenyl polycrystals excited by
conversion electrons of
137
Cs
This is characteristic of both polycrystalline stilbene
samples and p-terphenyl samples. This regularity also
actually does not depend on the type of radiation
excitation (alpha particles or conversion electrons).
Starting with grain fractions of 1.0…1.5, 1.5…2.0,
2.0…2.5 mm, the values of light collection coefficients
, transmittance T ( = 400 nm) and the relative light
output L stop increasing significantly and tend to
saturate. Therefore, to obtain an "opaque"
polycrystalline scintillation detector, we consider it
optimal to use crystal grains in the range 0.4…0.8 mm
(see, for example, Fig. 12).
CONCLUSIONS
The light output and optical transmittance of stilbene
and p-terphenyl polycrystals with the following
fractions of crystalline grains were studied, namely,
0.06…0.1, 0.1…0.3, 0.3…0.5, 0.5…1.0, 1.0…1.5,
1.5…2.0, and 2.0…2.5 mm (the samples 20 mm in
diameter and 2 mm in height). Modelling of light
transmission in polycrystalline samples of stilbene and
p-terphenyl scintillators obtained by the hot pressing
method was carried out. We calculated the values of
light collection coefficients of polycrystalline samples
both for the case of excitation by alpha particles, and
conversion electrons. It was found that in order to obtain
polycrystalline samples with sufficiently high light
output and high efficiency of detection of local
interaction sites of ionizing radiations, crystal grains in
the range of 0.4…0.8 mm should be used.
ACKNOWLEDGEMENTS
This work was supported by the National Research
Foundation of Ukraine, project № 2021.01/0042
“Development of effective detection systems for the
most harmful ionizing radiation for humans, for
radioecology tasks”.
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Article received 17.04.2023
ОСОБЛИВОСТІ ФОРМУВАННЯ СЦИНТИЛЯЦІЙНОГО ВІДГУКУ В ОРГАНІЧНИХ МАТЕРІАЛАХ
ІЗ СТОХАСТИЧНИМ ХАРАКТЕРОМ РОЗПОВСЮДЖЕННЯ СВІТЛА
Я.І. Полупан, І.В. Лазарєв, Є.В. Мартиненко, С.С. Міненко, О.А. Тарасенко, В.О. Тарасов
Досліджується можливість використання органічного полікристалa в якості «мутного» сцинтилятора.
Полікристали виготовляють методом пресування кристалічних гранул. Світло при розповсюдженні крізь
полікристал зазнає багаторазового відбивання та заломлення на границях гранул, що ускладнює його
проходження. Проведено дослідження світлового виходу та оптичного пропускання полікристалів
стильбену та п-терфенілу із різними фракціями кристалічних гранул: від 0,06…0,1 до 2,0…2,5 мм (діаметр
зразків 20 мм та висота 2 мм). Проведено моделювання проходження світла в полікристалічних зразках
стильбену та п-терфенілу, та розраховані значення коефіцієнтів світлозбирання в них. З’ясовано, що для
отримання полікристалічних зразків із достатньо високим світловим виходом та високою ефективністю
виявлення локальних місць взаємодії іонізуючого випромінювання слід використовувати гранули в
діапазоні 0,4…0,8 мм.
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