A possibility of photonuclear production of planar ¹⁷⁹Tа sources
Age-specific reduction of the bone mass (osteoporosis) is one of the most progressing human illness throughout the world. Its diagnostic is based on a measurement of the mineral density of bone mass by radiation absorptiometry technique. In the communication, a possibility to use gamma-sources on th...
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Dikiy, N.P. Lyashko, Yu.V. Rogov, Yu.V. Uvarov, V.L. 2017-01-17T15:38:52Z 2017-01-17T15:38:52Z 2013 A possibility of photonuclear production of planar ¹⁷⁹Tа sources / N.P. Dikiy, Yu.V. Lyashko, Yu.V. Rogov, V.L. Uvarov // Вопросы атомной науки и техники. — 2013. — № 6. — С. 188-191. — Бібліогр.: 12 назв. — англ. 1562-6016 PACS: 07.85.-m, 81.40wx,87.53-j,87.53Wz https://nasplib.isofts.kiev.ua/handle/123456789/112094 Age-specific reduction of the bone mass (osteoporosis) is one of the most progressing human illness throughout the world. Its diagnostic is based on a measurement of the mineral density of bone mass by radiation absorptiometry technique. In the communication, a possibility to use gamma-sources on the basis of the ¹⁷⁹Tа isotope for osteoporosis diagnostics is considered. The isotope can be produced by the ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа reaction in a high-energy X-ray radiation field using a target from natural tantalum. Conditions of the ¹⁷⁹Tа planar sources production at an electron accelerator were studied. By computer simulation, an optimization of target geometry has been conducted. Yield of target isotope and admixtures have been measured at a bremsstrahlung end-point energy of 40 MeV. Вікове зниження кісткової маси (остеопороз) є одним з найбільш прогресуючих видів захворювань у світі. Його діагностика заснована на вимірюванні мінеральної щільності кісткової маси методами променевої абсорбціометрії. Розглянута можливість використання для діагностики остеопорозу гамма-джерел на основі ізотопу ¹⁷⁹Tа (ЕХ~54 кeВ; Т₁/₂=665 днів). Його можна напрацьовувати в полі високоенергетичного гальмівного випромінювання за реакцією ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа у мішені з природного танталу. Досліджено умови отримання планарних джерел ¹⁷⁹Tа на прискорювачі електронів. Методом комп'ютерного моделювання проведена оптимізація геометрії мішеневого пристрою. Виміряні виходи цільового ізотопу і домішок при граничній енергії гальмівного випромінювання 40 МеВ. Возрастное снижение костной массы (остеопороз) является одним из наиболее прогрессирующих видов заболеваний в мире. Его диагностика основана на измерении минеральной плотности костной массы методами лучевой абсорбциометрии. Рассмотрена возможность использования для диагностики остеопороза гамма-источников на основе изотопа ¹⁷⁹Tа (ЕХ~54 кeВ; Т₁/₂=665 дней). Его можно производить в поле высокоэнергетического тормозного излучения по реакции ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа в мишени из природного тантала. Исследованы условия получения планарных источников ¹⁷⁹Tа на ускорителе электронов. Методом компьютерного моделирования проведена оптимизация геометрии мишенного устройства. Измерены выходы целевого изотопа и примесей при граничной энергии тормозного излучения 40 МэВ. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Применение ускоренных пучков. детекторы и детектирование ядерных излучений A possibility of photonuclear production of planar ¹⁷⁹Tа sources Можливість фотоядерного виробництва планарних джерел ¹⁷⁹Tа Возможность фотоядерного производства планарных источников ¹⁷⁹Tа Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources |
| spellingShingle |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources Dikiy, N.P. Lyashko, Yu.V. Rogov, Yu.V. Uvarov, V.L. Применение ускоренных пучков. детекторы и детектирование ядерных излучений |
| title_short |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources |
| title_full |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources |
| title_fullStr |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources |
| title_full_unstemmed |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources |
| title_sort |
possibility of photonuclear production of planar ¹⁷⁹tа sources |
| author |
Dikiy, N.P. Lyashko, Yu.V. Rogov, Yu.V. Uvarov, V.L. |
| author_facet |
Dikiy, N.P. Lyashko, Yu.V. Rogov, Yu.V. Uvarov, V.L. |
| topic |
Применение ускоренных пучков. детекторы и детектирование ядерных излучений |
| topic_facet |
Применение ускоренных пучков. детекторы и детектирование ядерных излучений |
| publishDate |
2013 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Можливість фотоядерного виробництва планарних джерел ¹⁷⁹Tа Возможность фотоядерного производства планарных источников ¹⁷⁹Tа |
| description |
Age-specific reduction of the bone mass (osteoporosis) is one of the most progressing human illness throughout the world. Its diagnostic is based on a measurement of the mineral density of bone mass by radiation absorptiometry technique. In the communication, a possibility to use gamma-sources on the basis of the ¹⁷⁹Tа isotope for osteoporosis diagnostics is considered. The isotope can be produced by the ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа reaction in a high-energy X-ray radiation field using a target from natural tantalum. Conditions of the ¹⁷⁹Tа planar sources production at an electron accelerator were studied. By computer simulation, an optimization of target geometry has been conducted. Yield of target isotope and admixtures have been measured at a bremsstrahlung end-point energy of 40 MeV.
Вікове зниження кісткової маси (остеопороз) є одним з найбільш прогресуючих видів захворювань у світі. Його діагностика заснована на вимірюванні мінеральної щільності кісткової маси методами променевої абсорбціометрії. Розглянута можливість використання для діагностики остеопорозу гамма-джерел на основі ізотопу ¹⁷⁹Tа (ЕХ~54 кeВ; Т₁/₂=665 днів). Його можна напрацьовувати в полі високоенергетичного гальмівного випромінювання за реакцією ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа у мішені з природного танталу. Досліджено умови отримання планарних джерел ¹⁷⁹Tа на прискорювачі електронів. Методом комп'ютерного моделювання проведена оптимізація геометрії мішеневого пристрою. Виміряні виходи цільового ізотопу і домішок при граничній енергії гальмівного випромінювання 40 МеВ.
Возрастное снижение костной массы (остеопороз) является одним из наиболее прогрессирующих видов заболеваний в мире. Его диагностика основана на измерении минеральной плотности костной массы методами лучевой абсорбциометрии. Рассмотрена возможность использования для диагностики остеопороза гамма-источников на основе изотопа ¹⁷⁹Tа (ЕХ~54 кeВ; Т₁/₂=665 дней). Его можно производить в поле высокоэнергетического тормозного излучения по реакции ¹⁸¹Ta(γ, 2n)¹⁷⁹Tа в мишени из природного тантала. Исследованы условия получения планарных источников ¹⁷⁹Tа на ускорителе электронов. Методом компьютерного моделирования проведена оптимизация геометрии мишенного устройства. Измерены выходы целевого изотопа и примесей при граничной энергии тормозного излучения 40 МэВ.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/112094 |
| citation_txt |
A possibility of photonuclear production of planar ¹⁷⁹Tа sources / N.P. Dikiy, Yu.V. Lyashko, Yu.V. Rogov, V.L. Uvarov // Вопросы атомной науки и техники. — 2013. — № 6. — С. 188-191. — Бібліогр.: 12 назв. — англ. |
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ISSN 1562-6016. ВАНТ. 2013. №6(88) 188
A POSSIBILITY OF PHOTONUCLEAR PRODUCTION
OF PLANAR 179Та SOURCES
N.P. Dikiy, Yu.V. Lyashko, Yu.V. Rogov, V.L. Uvarov
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
E-mail: uvarov@kipt.kharkov.ua
Age-specific reduction of the bone mass (osteoporosis) is one of the most progressing human illness throughout
the world. Its diagnostic is based on a measurement of the mineral density of bone mass by radiation absorptiometry
technique. In the communication, a possibility to use gamma-sources on the basis of the 179Ta isotope for osteoporo-
sis diagnostics is considered. The isotope can be produced by the 181Ta(γ, 2n)179Ta reaction in a high-energy X-ray
radiation field using a target from natural tantalum. Conditions of the 179Ta planar sources production at an electron
accelerator were studied. By computer simulation, an optimization of target geometry has been conducted. Yield of
target isotope and admixtures have been measured at a bremsstrahlung end-point energy of 40 MeV.
PACS: 07.85.-m, 81.40wx,87.53-j,87.53Wz
INTRODUCTION
Osteoporosis is the most widespread metabolic dis-
ease of bone system characterised by a loss of its
strength in view of decrease of the mineral bone density
(МBD). The most known nontraumatic method of the
osteoporosis in vivo diagnostics is a measurement of
МBD by a technique of radiation absorptiometry. The
method is based on a comparison of absorption coeffi-
cients of the photons with a specified energy (common-
ly in the range 30…100 keV) at their transmission
through the soft and bone tissues. The method is real-
ised by means of one- or two-photon absorptiometry
with the use of gamma sources on the basis of 125J
(Eγ =27.5 keV; Т1/2=60 day) and 153Gd (Eγ ~44 keV and
100 keV; Т1/2=241 day) isotopes or an X-ray source
(see, for example, [1]).
Both isotopes are received by radiochemical extrac-
tion from the targets irradiated on a reactor. In case of
X-ray radiation, an ultrastable tube with a system of
filters forming a spectrum with the two maxima nearly
45 and 80 keV are used [2]. To obtain a 2D-image, the
collimated source of γ-radiation and detector are syn-
chronously moved relative to an investigated part of the
skeleton situated between them. In view of complexity,
such equipment is rather expensive. So it is worthwhile
the development of a reactor free technology for pro-
duction of planar γ-sources with suitable energy of pho-
tons and big half-life. On their basis, it is possible de-
signing rather simple systems for osteoporosis diagnos-
tics, e.g., via inspection of peripheral parts of the skele-
ton. In the work, it is offered to use the 179Та isotope
(Table 1) for production of such sources. It can be gen-
erated by the reaction 181Та(γ, 2n)179Та having a thresh-
old of 14.2 МeV (Fig. 1).
1. OPTIMIZATION OF SOURCE
THICKNESS
Production of γ-sources on the basis of the 179Та iso-
tope can be realised by irradiation of a tantalum target
with the X-ray radiation of an electron accelerator with
beam energy E0 above the reaction threshold. It should
be noted that a free range of photons with energy
~20 МeV in tantalum makes ~1 cm [5]. Thus a Ta-target
thickness, within which the 179Та nuclei can be generated,
exceeds by two orders of values the free range of the pho-
tons emitted by this isotope (see Table 1). It stipulates a
necessity of optimisation of the source geometry to pro-
vide maximum of the 179Та activity at minimum of its
radiation self-absorption.
Table 1
Ta179 radiation spectrum [3]
Line Photon energy,
keV
Free range,
mm
Rel. intensity,
%
XR l 7.9 0.0036 20.2
XR kα1 54.07 0.1302 21.9
XR kα2 54.61 0.1336 12.6
XR kβ3 62.98 0.1945 2.44
XR kβ1 63.24 0.1966 4.71
XR kβ2 64.94 0.2112 1.61
10 15 20 25 30 35 40
0
50
100
150
200
C
ro
ss
-s
ec
tio
n
(m
b)
Photon energy (MeV)
Fig. 1. 181Та(γ, 2n)179Та reaction cross-section [4]
An obvious problem solving is the usage a stack of
thin foils as a target. In this case, it is possible to receive
a set of sources with essentially non-uniform distribu-
tion of surface activity corresponding to a profile of the
bremsstrahlung photon flux. Other variant, enabling to
receive an extended quasi-homogeneous source, is ap-
plication of a target in the form of a roll with its rotation
under activation.
The results of computer simulation of external radia-
tion of thin tantalum plates with evenly distributed 179Та
of identical total activity at different thickness t are
shown in Fig. 2.
It is seen that at a thickness t=1⋅10-6 cм, the photon
self-absorption is practically absent. However, at a giv-
en specific activity of 179Та the intensity of such source
will be small. At a thickness t >1⋅10-2 cm, there are only
mailto:uvarov@kipt.kharkov.ua
ISSN 1562-6016. ВАНТ. 2013. №6(88) 189
lines with energy ~54 and 64 keV in external radiation,
but their intensity considerably decreases in view of
self-absorption. Thus one of the features of photonucle-
ar 179Та technology is ensuring a compromise between
the activity of produced source and its area. A key pa-
rameter in this choice is the thickness of the produced
source t. Namely, at the given volume and general activ-
ity of a photonuclear target decreasing t is accompanied
by increasing of source area but dropping its activity.
Taking into account results of modelling, we have cho-
sen t=0.1 mm.
0 10 20 30 40 50 60 70
0
2
4
6
8
10
12
14
16
18
20
22
24
In
te
ns
ity
(%
)
Photon energy (keV) a
0 10 20 30 40 50 60 70
0
1
2
3
4
5
6
7
8
9
10
11
In
te
ns
ity
(%
)
Photon energy (keV) b
0 10 20 30 40 50 60 70
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
In
te
ns
ity
(%
)
Photon energy (keV) c
Fig. 2. External radiation of activated Ta plate:
a − t=1⋅10-6 cm; b − t=1⋅10-2 cm; c − t=1⋅10-1 cm
2. OPTIMIZATION OF TARGET
GEOMETRY
2.1. It is known that tantalum is widely used as a
material for the X-ray converters. Therefore we consider
a process of a Ta-target activation by direct acting on it
with an electron beam. Thus a considerable part of a
beam power is absorbed in the target. So for the 179Та
production at a high-current accelerator the target de-
sign should provide its effective cooling, for example,
with running water.
Taking into account these considerations, for analy-
sis and optimisation of the conditions of the 179Та pro-
duction it is offered a target device which scheme is
shown in Fig. 3. It represents a set from n tantalum
tubes inserted one into another (n=1, 2…6) − item1.
Each tube has a wall thickness of 1 mm. The aperture 2
of internal tube has a diameter of 10 mm. Thus with
increasing number n the external diameter of the device
will increase proportionally. The central channel of the
target as well as the gap 3 of 1 mm thick between the
surface of external tube and target casing 4 are filled
with cooling water. The casing corresponds a tube from
aluminium of 1 mm thick. Such choice of the target
geometry allows determine an optimum thickness of the
Ta-target by means of a layer-by-layer calculation of the
activity and absorbed radiation power.
We consider an electron beam with energy
Е0=40 МeV incident on the device surface. The given
value of energy seems to be nearly optimal taking into
account a yield of the above-threshold X-ray photons as
well as a rate of admixture generation. The beam has a
diameter of 0.5 cm with uniform distribution of particles
within its cross-section. The target is rotated under acti-
vation providing in such a way an axially symmetric
distribution of the induced 179Та activity and absorbed
radiation power.
e-
21 3 4n
Fig. 3. Diagram of target device (simulation)
2.2. Calculations were carried out by a simulation
technique on the basis of a modified PENELOPE-2008
package [6]. The data on the reaction 181Та(γ, 2n)179Та
cross-section, given in Fig. 1, were used for determining
the 179Та yield. The results of modelling are summarized
in Table 2. Their statistical error does not exceed 2 %.
The obtained data on the 179Та yield were reduced to
1 μA of beam current and 1 hour of irradiation run. The
data of Table 2 demonstrate that by increasing a thick-
ness of the Ta-target it is possible to increase a total
179Та yield. However, an average value of linear activity
of a received tape-like γ-source thus decreases. An en-
largement of its width can be ensured by moving the
target under activation along its axis or by application of
a scanned electron beam. Last variant seems to be pref-
erable in view of more uniform distribution of a thermal
loading on its elements, when the target is activated
with a high-power beam.
ISSN 1562-6016. ВАНТ. 2013. №6(88) 190
Table 2
Absorbed radiation power and yield of 179Та (Е0=40 MeV)
Thickness of Ta-target, mm 1 2 3 4 5 6
Length of 179Та source (t=0.1 mm), cm 34.5 75.4 122.5 175.8 235.5 301.4
Absorbed radiation power, W/μA:
Al-casing 0.96 0.84 0.64 0.55 0.52 0.52
water 2.88 3.22 3.13 2.66 2.05 2.05
tantalum 5.52 12.76 18.24 21.63 24.16 26.36
Yield of 179Та, μCi/μA⋅hour 0.85 2.7 4.4 6.0 7.3 8.3
Average linear activity of source,
nCi/μA⋅hour⋅cм 24.6 35.8 35.9 34.1 31.0 27.6
3. MEASUREMENT OF ISOTOPE
COMPOSITION OF ACTIVATED
Ta-TARGET
3.1. For estimating the accuracy of modelling as
well as yield of 179Та and impurities under tantalum
activation with the electron beam, an experiment, which
scheme is presented in Fig. 4, has been conducted.
e- 2
1
3
4
LU-40
Fig. 4. Scheme of experiment
At the exit of linac LU-40 [7] on the electron beam
axis, an aluminium branch pipe 1 of 400 mm length and
54 mm internal diameter was positioned. In the branch
pipe centre, a holder 2 was located with a target 3 con-
sisting of five Ta-plates each of 30 mm diameter. The
first four plates had a thickness of 1 mm and the fifth of
0.3 mm.
It is known that tantalum, irradiated with electrons,
besides X-ray (bremsstrahlung) radiation, generates also
a flux of photoneutrons, mainly, due to the 181Та (γ, n)
180mТа reaction (see, e.g., [8]). For study of influence of
the neutron spectrum on a radionuclide composition of
the activated target, in a separate experiment the branch
pipe with the target device was positioned in a modera-
tor of neutrons 4 (its detailed description is given in the
work [9]).
3.2. In each experiment, the target was irradiated at
40 МeV and 3.85 μА for 2 hours. After cooling during
24 hours for a decay of the short-live isotopes, the thin
tantalum plate was directed on a gamma-spectrometry
analysis. The measurements were conducted on a station
comprising an HPGe-detector (GPD-16195, BSI), an
ORTEC 570 amplifier and an ADC-8k-2b analog-to-
digital converter with a software An 2.5 (Aspect). The
station provides FWHM of 510 eV at 122.1 keV (57Со).
The results of measurements and simulation on the
yield of principal radionuclides under tantalum activa-
tion with neutron moderator and without it are given in
the Table 3.
Table 3
Yield of main isotopes under activation of tantalum with electron beam (Е0=40 МeV)
Isotope Т1/2, day Reaction Normalized yield, μCi/μA·hour·g
Without moderator With moderator Simulation
179Ta 665 181Ta(γ, 2n)179Ta 0.091 0.088 0.085
182Ta 114.4 181Ta(n, γ)182Ta 0.004 0.024 -
92mNb 10.15 93Nb*(γ, n)92mNb 0.001 0.001 -
* 93Nb is present in natural tantalum as a natural impurity
3.3. As it is seen from the data of the Table 3, the
yield of 179Та does not depend on the neutron spectrum,
and the results of modelling and experiment coincide
within 7% (that corresponds to an error of the activity
measurement). At the same time, the use of neutron
moderator is accompanied by the 6 times increase of the
182Та yield. It is caused by the increase of the 181Та (n,
γ) 182Та reaction cross-section up to ~20b in the thermal
area, as compared with ~100 mb at energy of photoneu-
trons of~100 keV [10]. In Fig. 5, the spectrum of tanta-
lum activated without moderator, and in Fig. 6 – the
low-energy fragments of the spectra for both variants of
the target activation are demonstrated.
300 600 900 1200 1500
channels
1
10
100
1000
10000
100000
co
un
ts
ju
vl
182TaTa179K +
K +
α
β
182Ta
92mNb
C
ou
nt
s
(a
rb
. n
or
m
al
iz
at
io
n)
Energy (keV)
Fig. 5. γ -spectrum of tantalum irradiated without mod-
erator of neutrons
ISSN 1562-6016. ВАНТ. 2013. №6(88) 191
40 60 80 100
channels
0
20000
40000
60000
co
un
ts
Ta179
K +
K +α
β
182Ta
Energy (keV) a
40 60 80 100
channels
0
20000
40000
60000
co
un
ts
Ta179
K +
K +α
β
182Ta
Energy (keV) b
Fig. 6. Spectra of tantalum activated by electron beam
(Е0=40 МeV): a − without moderator of neutrons;
b − with moderator
CONCLUSIONS
The γ-sources on the basis of 179Та can be produced
at the rather inexpensive and friendly for ecology electron
accelerators. In particular, with a beam (40 MeV; 1 mА)
it is possible to make for 100 hour run up to 30 planar
10×10 cm sources with activity of ~30 mCi each [11].
An advantage of the offered technology is also applica-
tion of targets from natural tantalum, which is practical-
ly a monoisotope. It delivers from a necessity to use the
expensive enriched materials, and also limits a number
of channels for impurity generation. Thus the activity of
main impurity 182Та right after EOB does not exceed 5%
and decreases further under a service of the γ-source. If
it is needed to increase the 182Та content (e.g., in order
to receive a many-photon source), a target activation
can be conducted using a moderator of neutrons.
In case of target activation using a high-current beam
(>10 А in the bunch), one can expect an increase of the
179Та and 182Та yield resulting from excitation of a short-
lived isomeric state of 181Та with energy 6.24 keV having
much greater cross-section of reactions [12].
REFERENCES
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G.M. Giannatempo, M. Camissa, H.K. Genant.
Quontative Computed Tomography at the Axial and
Peripherical Skeleton // Europ. Radiology. 1997,
v. 7, p. S22-S42.
3. www.nndc.bnl.gov/nudat2
4. Handbook on photonuclear data for Applications.
IAEA TECDOC-1178. 2000.
5. J.H. Hubbel. Photon Mass Attenuation and Energy-
absorption Coefficients from 1 keV to 20 MeV // Int.
J. Appl. Radiat. Isot. 1982, v. 33, p. 1269-1290.
6. F. Salvat, J.M. Fernández-Varea and J. Sempau.
“PENELOPE-2008. A Code System for Monte Carlo
Simulation of Electron and Photon Transport”.
OECD, NEA, Issy-les-Moulineaux, France, 2008.
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Physical Experimental Investigation // Problems of
Atomic Science and Technology. Ser. “Nuclear
Physics Investigations”. 2010, № 2(53), p. 18-22.
8. T.V. Malykhina, A.A. Torgovkin, A.V. Torgovkin,
et al. A study of mixed X,n-radiation under photo-
nuclear isotope production // PAST. Ser. «NPI».
2008, №5(50), p. 184-188.
9. V.L. Uvarov et al. Two-channel Mode of Mo-99
Production at an Electron Accelerator // Proc. of
Conf. IPAC 2011, San Sebastian, Spain, 2011,
p. 3627-3629.
10. Reference Neutron Activation Data. In: IAEA-
TECDOC-1285. April 2002, p.247.
11. N.P. Dikiy and V.L. Uvarov. Installation for produc-
tion of Ta-179 radioactive source // Patent of
Ukraine №83268, Bull. №16, 27.08.2013.
12. N.P. Dikiy et al. Excitation of isomeric low-lying
level of nucleus 181Ta by relativistic electrons //
PAST. Ser. «NPI». 2013, №3(85), p. 175-178.
Article received 27.09.2013
ВОЗМОЖНОСТЬ ФОТОЯДЕРНОГО ПРОИЗВОДСТВА ПЛАНАРНЫХ ИСТОЧНИКОВ 179Ta
Н.П. Дикий, Ю.В. Ляшко, Ю.В. Рогов, В.Л. Уваров
Возрастное снижение костной массы (остеопороз) является одним из наиболее прогрессирующих видов
заболеваний в мире. Его диагностика основана на измерении минеральной плотности костной массы мето-
дами лучевой абсорбциометрии. Рассмотрена возможность использования для диагностики остеопороза
гамма-источников на основе изотопа 179Та (ЕХ∼54 кэВ; Т1/2=665 дней). Его можно производить в поле вы-
сокоэнергетического тормозного излучения по реакции 181Та(γ, 2n)179Та в мишени из природного тантала.
Исследованы условия получения планарных источников 179Та на ускорителе электронов. Методом компью-
терного моделирования проведена оптимизация геометрии мишенного устройства. Измерены выходы целе-
вого изотопа и примесей при граничной энергии тормозного излучения 40 МэВ.
МОЖЛИВІСТЬ ФОТОЯДЕРНОГО ВИРОБНИЦТВА ПЛАНАРНИХ ДЖЕРЕЛ 179Та
М.П. Дикий, Ю.В. Ляшко, Ю.В. Рогов, В.Л. Уваров
Вікове зниження кісткової маси (остеопороз) є одним з найбільш прогресуючих видів захворювань у сві-
ті. Його діагностика заснована на вимірюванні мінеральної щільності кісткової маси методами променевої
абсорбціометрії. Розглянута можливість використання для діагностики остеопорозу гамма-джерел на основі
ізотопу 179Та (ЕХ∼54 кeВ; Т1/2=665 днів). Його можна напрацьовувати в полі високоенергетичного гальмів-
ного випромінювання за реакцією 181Та(γ, 2n)179Та у мішені з природного танталу. Досліджено умови отри-
мання планарних джерел 179Та на прискорювачі електронів. Методом комп'ютерного моделювання проведе-
на оптимізація геометрії мішеневого пристрою. Виміряні виходи цільового ізотопу і домішок при граничній
енергії гальмівного випромінювання 40 МеВ.
http://www.nndc.bnl.gov/nudat2
INTRODUCTION
1. OPTIMIZATION OF SOURCE THICKNESS
2. OPTIMIZATION OF TARGET GEOMETRY
3. MEASUREMENT OF ISOTOPE COMPOSITION OF ACTIVATED
Ta-TARGET
CONCLUSIONS
The-sourceson the basis of P179PТа can be produced at the rather inexpensive and friendly for ecology electron accelerators. In particular, with a beam (40 MeV; 1 mА) it is possible to make for 100 hour run up to 30 planar 10(10 cm sources with ac...
In case of target activation using a high-current beam (>10 А in the bunch), one can expect an increase of the P179PТа and P182PТа yield resulting from excitation of a short-lived isomeric state of P181PТа with energy 6.24 keV having much greater cros...
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