Subsystem for control of isotope production with linear electron accelerator
One of advanced ways of isotope production for medicine is using of bremsstrahlung of the electron accelerator [1]. Therewith, this technology requires development of special target units, that can be operated under high radiation energy flow (up to 10 kW and more) and absorbed doze up to 10¹⁰ Gy. T...
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2001
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| Цитувати: | Subsystem for control of isotope production with linear electron accelerator / S.P.Karasyov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, V.L. Uvarov // Вопросы атомной науки и техники. — 2001. — № 5. — С. 144-146. — Бібліогр.: 7 назв. — англ. |
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Karasyov, S.P. Pomatsalyuk, R.I. Shevchenko, V.A. Shlyakhov, I.N. Tenishev, A.Eh. Uvarov, V.L. 2015-03-24T17:08:03Z 2015-03-24T17:08:03Z 2001 Subsystem for control of isotope production with linear electron accelerator / S.P.Karasyov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, V.L. Uvarov // Вопросы атомной науки и техники. — 2001. — № 5. — С. 144-146. — Бібліогр.: 7 назв. — англ. 1562-6016 PACS number: 07.05.Bx https://nasplib.isofts.kiev.ua/handle/123456789/79003 One of advanced ways of isotope production for medicine is using of bremsstrahlung of the electron accelerator [1]. Therewith, this technology requires development of special target units, that can be operated under high radiation energy flow (up to 10 kW and more) and absorbed doze up to 10¹⁰ Gy. The conditions of high efficiency of the nuclide production and an isotope purity of them define requirements to the control and diagnostic systems. In this report the high-current LINAC subsystem for diagnostic and monitoring the basic technological parameters of isotope production (energy flux of bremsstrahlung photons and absorbed doze in the target, target activity, temperature and consumption of water cooling the converter and target) is described. The parallel printer port (LPT) of the personal computer is proposed to use as an interface with the measurement channels. Work is supported by STCU under contract N 2185. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Subsystem for control of isotope production with linear electron accelerator Подсистема контроля производства изотопов на линейном ускорителе электронов 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 |
Subsystem for control of isotope production with linear electron accelerator |
| spellingShingle |
Subsystem for control of isotope production with linear electron accelerator Karasyov, S.P. Pomatsalyuk, R.I. Shevchenko, V.A. Shlyakhov, I.N. Tenishev, A.Eh. Uvarov, V.L. |
| title_short |
Subsystem for control of isotope production with linear electron accelerator |
| title_full |
Subsystem for control of isotope production with linear electron accelerator |
| title_fullStr |
Subsystem for control of isotope production with linear electron accelerator |
| title_full_unstemmed |
Subsystem for control of isotope production with linear electron accelerator |
| title_sort |
subsystem for control of isotope production with linear electron accelerator |
| author |
Karasyov, S.P. Pomatsalyuk, R.I. Shevchenko, V.A. Shlyakhov, I.N. Tenishev, A.Eh. Uvarov, V.L. |
| author_facet |
Karasyov, S.P. Pomatsalyuk, R.I. Shevchenko, V.A. Shlyakhov, I.N. Tenishev, A.Eh. Uvarov, V.L. |
| publishDate |
2001 |
| language |
English |
| container_title |
Вопросы атомной науки и техники |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| format |
Article |
| title_alt |
Подсистема контроля производства изотопов на линейном ускорителе электронов |
| description |
One of advanced ways of isotope production for medicine is using of bremsstrahlung of the electron accelerator [1]. Therewith, this technology requires development of special target units, that can be operated under high radiation energy flow (up to 10 kW and more) and absorbed doze up to 10¹⁰ Gy. The conditions of high efficiency of the nuclide production and an isotope purity of them define requirements to the control and diagnostic systems. In this report the high-current LINAC subsystem for diagnostic and monitoring the basic technological parameters of isotope production (energy flux of bremsstrahlung photons and absorbed doze in the target, target activity, temperature and consumption of water cooling the converter and target) is described. The parallel printer port (LPT) of the personal computer is proposed to use as an interface with the measurement channels.
|
| issn |
1562-6016 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/79003 |
| citation_txt |
Subsystem for control of isotope production with linear electron accelerator / S.P.Karasyov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Tenishev, V.L. Uvarov // Вопросы атомной науки и техники. — 2001. — № 5. — С. 144-146. — Бібліогр.: 7 назв. — англ. |
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SUBSYSTEM FOR CONTROL OF ISOTOPE PRODUCTION
WITH LINEAR ELECTRON ACCELERATOR
S.P.Karasyov, R.I. Pomatsalyuk, V.A. Shevchenko, I.N. Shlyakhov, A.Eh. Ten-
ishev, V.L. Uvarov
National Science Center “Kharkov Institute of Physics and Technology”
61108, Kharkov, Ukraine
uvarov@kipt.kharkov.ua
One of advanced ways of isotope production for medicine is using of bremsstrahlung of the electron accelerator [1].
Therewith, this technology requires development of special target units, that can be operated under high radiation
energy flow (up to 10 kW and more) and absorbed doze up to 1010 Gy. The conditions of high efficiency of the nu-
clide production and an isotope purity of them define requirements to the control and diagnostic systems. In this re-
port the high-current LINAC subsystem for diagnostic and monitoring the basic technological parameters of isotope
production (energy flux of bremsstrahlung photons and absorbed doze in the target, target activity, temperature and
consumption of water cooling the converter and target) is described. The parallel printer port (LPT) of the personal
computer is proposed to use as an interface with the measurement channels.
PACS number: 07.05.Bx
1 INTRODUCTION
The main method of isotope production today is the
nuclear reactions initiated by heavy particles (basically
neutrons and protons), generated in the reactors and ac-
celerators. While the cross-sections of these reactions
are considerably higher then photonuclear ones, but a
charged particle interacting with the target looses the
energy very fast and leaves a resonance region. There-
fore an efficiency of the isotopes production (rate of iso-
tope nuclei generation per unit of the beam power) on
heavy particle accelerators is not very high [2]. In case
of reactors the problem is a large amount of the radioac-
tive waste created along with useful isotope production.
For example, if 1 Сi of the 99Мо (parent isotope of 99mTc
– the general nuclide using in medicine diagnostic) is
produced using the reactor then up to 50 Сi of long-
lived waste is produced too [3]. So, taking into account
a constant increase of isotope applying in medicine, a
creation of ecological safety technologies of their pro-
duction becomes more and more actual.
A bremsstrahlung of the electron accelerator can be
used for production of isotope series for biophysical and
medical purpose [4]. In this case, although the specific
activity of a produced isotope is relatively not so high (≤
1Ci/g), the efficiency of their generation is considerably
higher then in the case of using heavy charged particles
and neutrons [5]. Additionally, an isotope production
with using the electron accelerator is considerably lesser
in respect to concurrent production of radioactive iso-
topes then other technologies.
2 TECHNOLOGY OF ISOTOPE PRODUC-
TION ON THE ELECTRON ACCELERATOR
The schematic diagram of the setup for isotope pro-
duction using (γ,n) and (γ,p) reactions with a solid target
is shown in Fig. 1. The electron beam passes through an
accelerating structure AS, swings in line by a scanning
electromagnet SM and outputs to atmosphere through
an exit window. The sweep length and electron energy
are defined by the measurement channel with magne-
toinductive sensor SBPM [6]. Output beam is directed
to the target unit TE that includes: bremsstrahlung con-
verter C, target T and ionization chamber IC.
The converter presents aluminum case that has two
Ta –plates with thickness 1.2mm each (for an electron
energy in the range 20…30 MeV). The target T consists
of a set of the treated plates containing the initial isotope
and enclosed in an Al-casing. Running water continu-
ously cools down the converter plates and target plates.
AS
BM
SM
BP IB IM
e-
e-
U
SBPM
H2O
IIC
IC
TE
tC° NC
C T
tT° NT
Fig. 1. Schematic diagram of the setup for isotope pro-
duction with the electron accelerator.
A control subsystem of the target unit monitors con-
tinuously the water temperature at the converter (t°C)
and the target (t°T) output and output value of water
consumption NC and NT in these units. The copper ther-
mistors are used as temperature sensors, and the turbine
converters are used as water consumption sensors [6].
3 OPERATION CONTROL OF
BREMSSTRAHLUNG AND TARGET AC-
TIVITY
3.1. The technological measurement channel for
metrological accompaniment of the radionuclide pro-
duction process using the electron accelerator is devel-
oped. It controls the following parameters:
- bremsstrahlung energy flux,
144
mailto:uvarov@kipt.kharkov.ua
- absorbed dose rate and absorbed doze of
bremsstruhlung in the target,
- target activity,
- converter and target cooling water temperature and
its consumption.
3.2. For the continuous monitoring and control of
bremsstrahlung parameters a sensor low disturbing a ra-
diation field is needed. Considering above-mentioned
circumstances, the plane-parallel wide-aperture ioniza-
tion chamber IC with a sensitive region size
220х550 mm was developed and constructed as a mea-
surement probe. The chamber is made from aluminum
and its effective thickness is 0.6 g/sm2 [7].
The choice of geometrical parameters of the IC is
defined by conditions of bremsstrahlung generation
(BR). The BR in modern electron accelerators is pro-
duced by conversion of the initial high-power electron
beam (10 kW). Since such beam swings into the line be-
fore output to the atmosphere, this defines increasing of
a geometrical size both in initial electron beam and
bremsstrahlung too.
3.3. The automate system for input and signal pro-
cessing from the ionization chamber, temperature chan-
nel and water flowmeter is constructed (Fig. 2). The
system is modularized and has four measurement chan-
nels.
Linear
commutator
ADG608
Inp.1
FromLPT
In LPT
Water flux sensor Convert. f/U
Thermoresistor 1 Preamplifier
ADC
AD7895
Norm.ampl.
IC
Varying
preamplifier+U Integrator
Current
generator
Thermoresistor 2 Preamplifier
Inp.2
Inp.3
Inp.4
FromLPT
Ustandard
R
Fig. 2. Block-diagram of the control-measurement
channel using LPT-port.
The power supply +250 V with a stability about
10-3% is developed for a chamber feed that works in the
current mode. The load of the chamber IC is the mea-
surement resistor R. A potential from this resistor (that
is proportional to the amount of energy stream through
the chamber or absorbed doze rate of bremsstrahlung in
point of its interaction with an irradiated object) goes to
the input of the preamplifier. The latter is an inverter
with various gain coefficients and made using the ana-
log IC AD711. From the output of the preamplifier the
amplified signal goes to the integrator with a time con-
stant τ ≈1.5 sec, that is much more than the period of the
accelerator pulse rate and beam scanning. In other
words, the signal at the integrator output is proportional
to the IC current, averaged over the period τ. Then the
signal going to the input of the linear commutator is
controlled by the computer.
The beam is turned off in the mode of activity mea-
surement and the tract of activity measurement is con-
nected to the ionization chamber. This tract is similar to
the measurement tract of absorbed radiation doze rate
and a difference is only the preamplifier gain. The
changing of the preamplifier gain is provided by the re-
sistor connection to the feedback of the preamplifier
through the commutator controlled by the computer.
The temperature tract consists of two identical chan-
nels that make measurement of temperature water, cool-
ing converter and target. The copper termistors with a
resistance R0 =50 Ω are used as the primary sensors and
connected as is shown in Fig. 2. The preamplifiers of
DC current use analog IC type of AD623 and have gain
~ 103. The current generator has stability better than 10-4
%. A signal from the preamplifier output is going to the
linear commutator and digitized by 12-bits ADC. The
accuracy of measurement is about 0.010С with noted
channel parameters.
3.4. The standard water flowmeter ТПР-10-1-1В
was chosen as primary probe for the water consumption
measurement. An output voltage (that is proportional to
the water flow in system) from the flowmeter is applied
to the input of the linear commutator.
From the commutator the signal goes to the input of
the buffer amplifier, that is made as non-inverting volt-
age amplifier with a high input impedance and then sig-
nal goes to the ADC input. The selection of the mea-
surement channel is controlled by commands from the
computer.
In the course of system operation the following pa-
rameters are measured and output to the display:
1 – bremsstrahlung energy flux,
2 – absorbed doze of bremsstrahlung in the target,
3 – target activity,
4 – time of target exposure,
5 – temperature and consumption of cooling water.
After achievement of target activity preset, the sys-
tem generates a control signal for beam accelerator
switch off.
4 INTERFACE BETWEEN CONTROL SYS-
TEM AND COMPUTER
A traditional use of known standards like IEEE-488,
CAMAC is unreasonably expensive and in many cases
controller interface cards are not supported by modern
personal computers (P-II, P-III) because of the high
CPU speed and mode Plug and Play.
The parallel printer port (LPT) is proposed to use as
an alternative variant of the interface between the mea-
surement equipment and personal computer. This port is
supported by all IBM personal computers and does not
require building of additional interfaces.
Three registers (Fig. 3) control a printer port in the
computer. 12 lines are used for the data sending to the
printer and printer control as output and 5 lines are used
as an input for the data sending to the computer.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №5.
Серия: Ядерно-физические исследования (39), с. 145-146.
145
Parallel Port
Connector
Pa
ra
lle
l
D
ev
ic
e
Pin Signal Name
1 - Store
2 + Data Bit 0
3 + Data Bit 1
4 + Data Bit 2
5 + Data Bit 3
6 + Data Bit 4
7 + Data Bit 5
8 + Data Bit 6
9 + Data Bit 7
10 - Acknowledge
11 + Busy
12 + Paper End
13 + Select
14 - Auto Feed
15 - Error
16 - Initialise Printer
17 - Select Input
18-25 Ground
All outputs are generated by software;
all inputs are real-time (nonlatched) signals
Fig. 3. Signals assignment of the LPT-port.
This number of lines is enough for the control mea-
surement system and acceptance of data from it. The use
of a serial ADC AD7895 allows to provide data stream
rate up to 120kbod, that is sufficiently for the systems
with low and medium data stream rates.
Because a modern printer port uses a bidirectional
data bus, it allows to use the parallel ADC and increase
the exchange data rate about up to 10 times.
The drivers for system control were written with the
high-level language Pascal, that allows to simplify pro-
gramming significantly without lose of the response
speed.
5 ACKNOWLEDGMENTS
Work is supported by STCU under contract N 2185.
REFERENCES
1. M.H. Mac Gregor. Linear Accelerators as Ra-
dioisotope Producers. Nucleonics.
2. M.C.Lagunas-Solar et al. Cyclotron Production of
Molibdenum-99 via Proton-Induced Uranium-238
Fission // Trans. Amer. Nucl. Soc. 1996, v. 74,
p. 134-135.
3. W.van Z. Villiers. Proc. Nucl. and Hazardous
Waste Managem. Inter. Topical Meet. 14-18 Aug.
1994, Atlanta, USA, p. 2190-2192.
4. N.P.Dikiy, A.N.Dovbnya, S.V.Maryokhin,
V.L.Uvarov. On Production Efficiency of Medical
& Biophysical Isotopes Using the Electron Acceler-
ator // Problems of Atomic Science and Technology.
Issue: Nuclear-Physics Research (34). 1999, v. 3,
p. 91.
5. R.G.Bennett et al. A System of 99mTc Production
Based on Distributed Electron Accelerators and
Thermal Separation // Nucl. Technol. 1999, v. 126,
p. 102-121.
6. V.L.Uvarov, V.N.Boriskin, S.P.Karasyov et al.
Electron Linac Controlling Subsystem for Isotopes
Production Technologies // Proc. of Workshop on
Personal Computer and Particle Accelerator Con-
trols PCaPAC 2000, Oct. 9-12, 2000, DEZY, Ham-
burg, Germany, p. 127.
7. A.A.Butenko, S.P.Karasyov, R.I.Pomatsalyuk et al.
Technological Measuring Channel for
Bremsstrahlung Monitoring // Problems of Atomic
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