Technological measuring channel for bremsstrahlung monitoring
For metrological support of radiation technological processes based on braking radiation (bremsstrahlung) of the electron accelerator necessary is continuous monitoring of next radiation parameters: energy stream and energy of bremsstrahlung (B), density of energy stream and transfer of energy of br...
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| Published in: | Вопросы атомной науки и техники |
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| Date: | 1999 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
1999
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| Cite this: | Technological measuring channel for bremsstrahlung monitoring / A.A. Butenko, S.P. Karasyov, R.I. Pomatsalyuk, A.Eh. Tenishev, V.L. Uvarov, V.A. Shevchenko, I.N. Shlyakhov, I.I. Tsvetkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 49-51. — Бібліогр.: 4 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860107513458851840 |
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| author | Butenko, A.A. Karasyov, S.P. Pomatsalyuk, R.I. Tenishev, A.Eh. Uvarov, V.L. Shevchenko, V.A. Shlyakhov, I.N. Tsvetkov, I.I. |
| author_facet | Butenko, A.A. Karasyov, S.P. Pomatsalyuk, R.I. Tenishev, A.Eh. Uvarov, V.L. Shevchenko, V.A. Shlyakhov, I.N. Tsvetkov, I.I. |
| citation_txt | Technological measuring channel for bremsstrahlung monitoring / A.A. Butenko, S.P. Karasyov, R.I. Pomatsalyuk, A.Eh. Tenishev, V.L. Uvarov, V.A. Shevchenko, I.N. Shlyakhov, I.I. Tsvetkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 49-51. — Бібліогр.: 4 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | For metrological support of radiation technological processes based on braking radiation (bremsstrahlung) of the electron accelerator necessary is continuous monitoring of next radiation parameters: energy stream and energy of bremsstrahlung (B), density of energy stream and transfer of energy of bremsstrahlung, rate of absorbed doze and absorbed doze of bremsstrahlung, in range of energy of braking photons 5..50MeV. For realization of these requirements the technological measuring channel with primary sensor in the form of wide aperture thin-walled ionization chamber was developed by authors. The structure and metrological characteristics of the channel are described in this paper.
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| first_indexed | 2025-12-07T17:32:29Z |
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TECHNOLOGICAL MEASURING CHANNEL FOR BREMSSTRAHLUNG
MONITORING
A.A.Butenko, S.P.Karasyov, R.I. Pomatsalyuk, A.Eh.Tenishev, V.L.Uvarov, V.A.Shevchenko,
I.N.Shlyakhov, I.I.Tsvetkov*
NSC KIPT, Kharkov, Ukraine, *D.I.Mendeleyev Institute (VNIIM), St.Petersburg, Russia
INTRODUCTION
For metrological support of radiation
technological processes based on braking radiation
(bremsstrahlung) of the electron accelerator necessary is
continuous monitoring of next radiation parameters:
energy stream and energy of bremsstrahlung (B) ,
density of energy stream and transfer of energy of
bremsstrahlung,
rate of absorbed doze and absorbed doze of
bremsstrahlung,
in range of energy of braking photons 5..50MeV.
For realization of these requirements the
technological measuring channel with primary sensor in
the form of wide aperture thin-walled ionization
chamber was developed by authors. The structure and
metrological characteristics of the channel are described
in this paper.
1. THE MEASURING CHANNEL STRUCTURE
The measuring channel of bremsstrahlung
parameters includes primary measuring sensor – freeair
ionization chamber IC-W and signal processing system.
The choice of geometrical characteristics of the
IC-W is determined by conditions of bremsstrahlung
generation in modern electron accelerators.
Bremsstrahlung is produced by conversion of primary
high power electron beam (>10kW). The primary
electron beam of large intensity is scanned before it
bring out to atmosphere, that determines magnification
of geometric sizes of a field both primary and secondary
radiation.
In conditions of radiation technological setups
using bremsstrahlung the continuous not disturbing
monitoring of its parameters is necessary. Taking into
account reduced circumstances, as the primary
measuring sensor the plane-parallel wide-aperture
ionization chamber (IC) with a size of sensing area 220⋅
555(sm2) was developed. The chamber is made from
aluminum and its effective thickness is 0.6 g/ sm2.
For signal processing of IC-W sensor the
measuring tract was created (Fig.1)
Fig. 1. The block diagram of the measuring channel for
bremsstrahlung
The measuring channel is constructed on a
modular principle, namely, for its operation are
necessary only to apply voltage on IC (+250 V) and
feed on the elements of the measuring tract (~220 V).
For a feed of the chamber, which works in a
current condition, the power supply (PS) with stability
not worse 10-5 is developed. The measuring resistor R is
the load of the chamber IC-W. From the resistor R the
signal, which is proportional to the value of energy
stream through the chamber or to an average absorbed
doze rate in the point of interaction of breamsstrahlung
and irradiated object, arrives on input amplifier (IA) .
The IA is an inverter with gain about 10 and it is
implemented on OA type 544UD2. From the exit of the
IA an amplified signal arrives on the active integrator
(I). Its a time constant is τ=1.5s, that is much more than
inversed frequencies of the accelerator and scanning of
beam. Or else, the signal on the I exit is proportional to
a current of IC-W, averaged by period τ. From the exit
of the I the signal arrives on input of normalizing
amplifier (NA). The NA is non inverting amplifier with
high input resistance and gain 20, it is implemented on
OA type 544UD2. From the exit of NA the signal goes
to the input of the converter "voltage-to-frequency"
(VFC). The converter is carried out on basis of the
integrated circuit KP110PP1 (analog ICL8068). The
nonlinearity of transformation does not exceed 0.01 %
in a frequency band 0... 10kHz. The signal produced by
VFC in digital forms arrives to the microcontroller unit
(MC). The latter makes accounts of input pulses and it
has a panel D for display of an information (matrix of
LED indicators) and keyboard K for the set up one from
the following operational modes of MC:
1 -definition and indication of an energy stream of
bremsstrahlung;
2 -definition and indication of an energy value
(absorbed doze) of bremsstrahlung;
3 -definition and indication of exposition time;
MC unit outputs control signal for alarm, when
the setting exposition doze is reached. It is implemented
on base of IC type 1816VE31 (analog Intel 8031).
Executing program in volume 2kB is store in external
ROM type K573RF5.
2.THE METHODS FOR MEASURING CHANNEL
RESEARCH
2.1. For metrological research of measuring
channel on base of IC-W sensor the method of computer
simulation with software package ‘GEANT’ and with
real geometric conditions of system (electron radiation-
cooling by water converter of bremsstrahlung-air gap-
collimator) was used (Fig.2). The dependence of the
bremddtrahlung (B) energy stream on the output of
collimator from electron energy was studied. Besides,
the comparator methods using the standard ionization
chamber IKV-6 from Standard 72-90 developed in
VNIIM was used.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 49-51.
49
2.2. For measuring energy stream of B the next
expression was used:
ΦE=k1(Eγ)⋅n, (1)
where n is count rate of pulse in measuring tract(c-1);
k1 is coefficient, depended from energy of γ-quantums
of B and defined in result of calibration.
For measuring of B density of energy stream the
next expression is used:
ϕE= ΦE /S, (2)
where S is area of input collimator placed in front of the
IC-W sensor.
For measuring of energy of B the next expression
is used:
∑ ⋅=
T
E nEkW ,)(1 τγ (3)
where T is exposition time of the IC-W in field of B.
The energy transfer of B is obtained from the
formula
∑ ⋅=
T
E n
S
Ek
w ,
)(1 τγ
(4)
The absorbed dose rate of B is obtained from the
formula:
,)()( ,
d
d
dm n
n
t
D
ESED ⋅
∆
⋅=
•
γγ (5)
where Dd is value of absorbed doze measured by the
dosimeter’s absorber for time exposition ∆t,
Sm,d(Eγ) is relationship between mass stopping power
coefficients of absorber and dosimeter,
nd is count rate of pulses in measuring channel during
calibration .
The absorbed dose of B is obtained from the next
expression:
,)()( ,
d
Td
dm n
n
t
D
ESED
∑ ⋅
⋅
∆
⋅=
τ
γγ
(6)
3. METHOD OF MEASUREMENT
3.1. For metrological research of measuring
channel the scheme on Fig.2 was used.
Fig.2. Scheme of measurement (not scanned
electron beam): A-accelerator LINAC-10;
C-converter; Cl- collimator (Pb, 200mm).
The construction of the converter C provides its a
galvanic isolation to ground, that allows using the
converter as the Faraday cup for additional monitoring
of electrons a stream during measurements
Before the beginning of the measurements of the
B parameters the following characteristics of the
electron beam were measured. In this case the next
parameters were monitored:
• Magnitude of a stream of electrons (by the built-in
Faraday cup FC-2),
• Power spectrum (by the magnetic analyzer),
• Amplitude of a current in impulse (by built-in
Rogovsky coil),
• Geometric performances (by mark on a irradiated
glass).
For measurements in conditions of a not scanned
electron beam the following parameters were
monitored:
• the account rate of pulses n (s-1) in a measuring
tract IC-W,
• average current of the primary ionization chamber
IKV-6 (by device В-7-40),
• average current of the converter (by device В3-
27).
3.2. For metrological research of measuring
channel in conditions of power scanned electron and
brake radiation the scheme of measurement shown on
Fig.3 was used.
Fig.3. Scheme of measurement
(scanned electron beam): A-accelerator
LINAC-20; C-converter;
F- filter (Al with thickness 45mm).
• the account rate of pulses n (s-1) in a measuring tract
IC-W, Pγ;
• electron beam pulse current I (by Rogovsky coil and
converter current);
• electron energy (probable value) by electron beam
length in scanning device;
• frequency of accelerator repetitions (by frequency-
meter );
• geometrical size of brake radiation field (by mark on
a glass placed after filter F).
4. RESULTS OF MEASUREMENTS
For realization of measurements in conditions of
not scanned electron beam of the accelerator LINAC-10
the energy of electrons in a maximum of a spectrum was
in range 10...16 MeV. The results of measurements are
demonstrated in Fig.4.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 49-51.
49
For realization of measurements in conditions of
the scanned electron beam (accelerator LINAC-20) the
energy of electrons in a maximum of a spectrum was
21MeV. The geometrical size of the brake radiation
field after filter F as~200x500mm2. The results of
measurements are shown in Fig.5.
Fig.4. Bremstrahlung power dependence on pulse
current amplitude
Fig.5. Bremstrahlung power dependence of beam pulse
repetition rate
SUMMARY
1.Thus as result the technological measuring
channel of was created and investigated for measuring
of next physical parameters and values range of
bremsstrahlung:
energy stream of bremsstrahlung (B), W
1.0⋅10-1…1.0⋅104,
density of energy stream of B, W⋅m-2
1.0⋅101…1.0⋅106,
energy transfer of B, J⋅m-2
1.0⋅10-2…1.0⋅109,
absorbed dose rate of B, Gr⋅s-1
1.0⋅10-3…1.0⋅1010,
absorbed dose of B, Gr
1.0⋅103…1.0⋅1011,
with next metrological characteristics:
main error in measurement of energy stream and density
of energy stream, energy and energy transfer of B
with confidence interval 0.95
-not more than 10%;
additional error connected with energy range of
radiation - not more than 2%
additional error connected with measurement range
- not more than 3%;
error in measurement of the absorbed dose rate and
absorbed dose of bremsstrahlung
– not more than 20%;
coefficient of conversion for measurement of energy
stream, density of energy stream, energy and energy
transfer of the B
K1=2.42⋅10-1 J/pulse.
2. The measuring channel on base of the
ionization chamber IC-W has passed the metrological
certification in VNIIM and can be used as operation
instrument including the radiation technological setups
with electron accelerators.
REFERENCES
1. Beloglazov V.I. et al. // Ser. Fiz. Rad. povrezhd. i radiaz.
materialoved. Kharkov, 1986, N 1(98), s.89-91.
2. Avdeev Yu.V. et al. Metrological investigation of electron-
radiation measuring devices for LU-10 and LU-40
accelerators.// Prepr. KIPT. 91-6, Kharkov, Kipt, 1991.
3. A.N.Dovbnya et al. Electron Linacs Based Radiation
Facilities of Ukrainian National Science Center “KIPT” //
Bull. of Amer. Phys. Soc., 1997, v.42, N 3, p.1391.
4. Eran L.V. et al. Automatic magnet analyzer for electron
flux energetic spectrum. See Proc. of this Conference
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 1999. № 4.
Серия: Ядерно-физические исследования (35), с. 49-51.
49
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| id | nasplib_isofts_kiev_ua-123456789-81529 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T17:32:29Z |
| publishDate | 1999 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Butenko, A.A. Karasyov, S.P. Pomatsalyuk, R.I. Tenishev, A.Eh. Uvarov, V.L. Shevchenko, V.A. Shlyakhov, I.N. Tsvetkov, I.I. 2015-05-17T16:46:33Z 2015-05-17T16:46:33Z 1999 Technological measuring channel for bremsstrahlung monitoring / A.A. Butenko, S.P. Karasyov, R.I. Pomatsalyuk, A.Eh. Tenishev, V.L. Uvarov, V.A. Shevchenko, I.N. Shlyakhov, I.I. Tsvetkov // Вопросы атомной науки и техники. — 1999. — № 4. — С. 49-51. — Бібліогр.: 4 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/81529 For metrological support of radiation technological processes based on braking radiation (bremsstrahlung) of the electron accelerator necessary is continuous monitoring of next radiation parameters: energy stream and energy of bremsstrahlung (B), density of energy stream and transfer of energy of bremsstrahlung, rate of absorbed doze and absorbed doze of bremsstrahlung, in range of energy of braking photons 5..50MeV. For realization of these requirements the technological measuring channel with primary sensor in the form of wide aperture thin-walled ionization chamber was developed by authors. The structure and metrological characteristics of the channel are described in this paper. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Technological measuring channel for bremsstrahlung monitoring Технологический измерительный канал для мониторинга тормозного излучения Article published earlier |
| spellingShingle | Technological measuring channel for bremsstrahlung monitoring Butenko, A.A. Karasyov, S.P. Pomatsalyuk, R.I. Tenishev, A.Eh. Uvarov, V.L. Shevchenko, V.A. Shlyakhov, I.N. Tsvetkov, I.I. |
| title | Technological measuring channel for bremsstrahlung monitoring |
| title_alt | Технологический измерительный канал для мониторинга тормозного излучения |
| title_full | Technological measuring channel for bremsstrahlung monitoring |
| title_fullStr | Technological measuring channel for bremsstrahlung monitoring |
| title_full_unstemmed | Technological measuring channel for bremsstrahlung monitoring |
| title_short | Technological measuring channel for bremsstrahlung monitoring |
| title_sort | technological measuring channel for bremsstrahlung monitoring |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/81529 |
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