Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20
In view of the requirements for the new accelerator KUT-20, results of the preoperational test-bench development of electromagnetic scanner characteristics are reported. Urgent tasks are outlined for further improvement of the whole extraction unit.
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
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| Zitieren: | Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 / A.N. Dovbnya, A.E. Tolstoj, V.A. Shendrik, T.A. Semenets // Вопросы атомной науки и техники. — 2001. — № 3. — С. 124-125. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-792532015-03-31T03:02:48Z Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 Dovbnya, A.N. Tolstoj, A.E. Shendrik, V.A. Semenets, T.A. In view of the requirements for the new accelerator KUT-20, results of the preoperational test-bench development of electromagnetic scanner characteristics are reported. Urgent tasks are outlined for further improvement of the whole extraction unit. 2001 Article Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 / A.N. Dovbnya, A.E. Tolstoj, V.A. Shendrik, T.A. Semenets // Вопросы атомной науки и техники. — 2001. — № 3. — С. 124-125. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS nambers: 07.55.+ X http://dspace.nbuv.gov.ua/handle/123456789/79253 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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In view of the requirements for the new accelerator KUT-20, results of the preoperational test-bench development of electromagnetic scanner characteristics are reported. Urgent tasks are outlined for further improvement of the whole extraction unit. |
| format |
Article |
| author |
Dovbnya, A.N. Tolstoj, A.E. Shendrik, V.A. Semenets, T.A. |
| spellingShingle |
Dovbnya, A.N. Tolstoj, A.E. Shendrik, V.A. Semenets, T.A. Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 Вопросы атомной науки и техники |
| author_facet |
Dovbnya, A.N. Tolstoj, A.E. Shendrik, V.A. Semenets, T.A. |
| author_sort |
Dovbnya, A.N. |
| title |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 |
| title_short |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 |
| title_full |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 |
| title_fullStr |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 |
| title_full_unstemmed |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 |
| title_sort |
formation of scanner magnetic-optical characteristics in the nsc kipt new-generation electron linac kut-20 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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2001 |
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http://dspace.nbuv.gov.ua/handle/123456789/79253 |
| citation_txt |
Formation of scanner magnetic-optical characteristics in the NSC KIPT new-generation electron linac KUT-20 / A.N. Dovbnya, A.E. Tolstoj, V.A. Shendrik, T.A. Semenets // Вопросы атомной науки и техники. — 2001. — № 3. — С. 124-125. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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| first_indexed |
2025-07-06T03:17:49Z |
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2025-07-06T03:17:49Z |
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| fulltext |
FORMATION OF SCANNER MAGNETIC-OPTICAL
CHARACTERISTICS IN THE NSC KIPT NEW-GENERATION
ELECTRON LINAC KUT-20
A.N. Dovbnya, A.E. Tolstoj, V.A. Shendrik, T.A. Semenets1
SPC “Accelerator”, National Science Center “Kharkov Institute of Physics and Technology”,
Kharkov, Ukraine
1 Kharkov National University of Radioelectronics,
Kharkov, Ukraine
In view of the requirements for the new accelerator KUT-20, results of the preoperational test-bench development of
electromagnetic scanner characteristics are reported. Urgent tasks are outlined for further improvement of the whole
extraction unit.
PACS numbers: 07.55.+ X
The operating experience of technological electron
accelerators at KIPT gives evidence that these devices
can be used to solve a wide range of applied and re-
search problems. Considerable recent interest has been
shown to this class of electron linacs (ELA) on the radi-
ation medicine side, in particular, for production of
medical radionuclides. At the same time, the calcula-
tions show that an advantageous solution of the prob-
lems is possible if the following conditions are provid-
ed:
- increase in the accelerated electron energy up to E0≥
25-40 MeV and a rise in the average extracted-beam
current up to 1 mA;
- effective high-power beam extraction from vacuum to
the atmosphere into the target-converter;
- formation of linear-angular beam characteristics at the
exit window (long-time reliability) and at the converter
(maximum current density);
- a possibility of prompt accelerated electron energy
control without interrupting the technological process.
The last two conditions impose stricter requirements
on the design, manufacturing methods, arrangement and
calibration of magnetic elements of electron beam for-
mation in the scanner-exit window-target section.
Among other issues, these ones were of crucial impor-
tance in the process of creating a new ELA - KUT-20
[1]. The methods of tackling the arising problems have
been developed and improved during the preopera-
tional-up period and the following service of now-oper-
ating devices [2, 3]. The decisive steps of the work
should be the comprehensive investigations and devel-
opment of magnetic characteristics of the device at
“cold conditions” at the test bench [4].
The main scanner’s unit - sweeping electromagnet
(SEM) - was originally designed for the first ELA to be
operated at E≅10 MeV, ϕmax≈±20°; the reduced field
strength in the magnet gap was required to be Hm
≈ 0.075 T and the sawtooth current amplitude - to be I ≈
±20 A [2]. Similar operating conditions have appeared
acceptable for the following two accelerators of the
same class.
From May to December, 2000, the work on preoper-
ational preparation of electromagnetic equipment for the
KUT-20 and LU-10 exit units was done at the test bench
of the SPC “Accelerator”. The scope and level of inves-
tigations were assigned by the above-given conditions.
First of all, it was necessary to establish the poten-
tialities of the equipment in providing the magnetic field
strength value and the field quality as applied to the
electron energy above 20 MeV. To this end, complying
with the recommendations of [4] and using the NMR-
nutation method we have eliminated several functions
of type H=f(Iexc) in the range Iexc= (0 ... 30) A with a ∆
I=2A step. As a result, the calibration derivative dH/dI =
36.578 Oe/A was obtained, and theinearity of the func-
tion H(Iexc) was established (within the measurement er-
ror) up to Iexc ~30A, this corresponding to Hop = ± 0.11T.
To determine the spatial characteristics of the mag-
netic field (nonlinearity in radius dH/dr, effective angle
of particle rotation in the magnet ∫
+ ∞
∞−
Η
ρH
1
z dl), the
field measurements were made on the graticule with a ∆
lx∆r=1sm step along the principal trajectories of elec-
tron beam sweep with an exact reference to the input
and output boundaries.
The integration and processing of the measurements
have given Ln =164.12 mm; dH/H≤10-3.
The studies into magnetic characteristics of the a.c.
scanner have called for the development and use of new
measuring and calibrating means: induction monitors
(IM) and Helmholtz coils (HC). A number of induction
coils were developed and created as applied to our con-
ditions. The one-layered IM with a total area of turns
SW=0.08148 m2 has appeared the most acceptable. The
monitor in combination with the oscillograph S8-17
provided measurements in a wide range of current and
frequency values (Iexc and fI) in both the scanner electro-
magnet and the HC.
Recall that the extracted electron beam energy is
controlled at our conditions with the use of the standard
electromagnet of scanner. In this case, the excitation
current value (Iexc, formula in [4]) is determined from
the signal read from the calibrated shunt (S) in the exci-
tation circuit. Considering that the electromagnet with
iron for alternating current is the reactive load, one
would expect first a voltage-current phase shift, and sec-
ondly, the losses in the iron of the magnetic circuit.
These phenomena are strongly dependent on the Iexc fre-
quency and the ferromagnetic core structure.
ВОПРОСЫ АТОМНОЙ НАУКИ И ТЕХНИКИ. 2001. №3.
Серия: Ядерно-физические исследования (38), с. 124-125.
124
For quantitative studies of the effects, the measure-
ment scheme had to be complicated and improved. It
was decided to measure the magnetic field strength in
the SEM clearance (spatial homogeneity region) by
three methods simultaneously: by the current shunt sig-
nal, the induction monitor and the NMR signal (for
f = 3Hz). The same was done at f = 50 Hz (except for
the NMR).
Similar measurements were also performed for the
HC, the other conditions being the same. The final re-
sults of all the mentioned measurements are, in our
opinion, of more than a special interest.
SEM
(f=50Hz, S+IM) →
Η
∆ Η
=2
IMS
IMS
Η+Η
Η−Η
_+6.5⋅10-2
HC
(f=50Hz, S+IM) →
Η
∆ Η
=2
IMS
IMS
Η+Η
Η−Η
_+2.5⋅10-2
SEM
(f=3 Hz, S + NMR) →
Η
∆ Η
≤+1⋅10-2.
So, in all the cases, the H value measured by the “di-
rect method” (NMR, IM) turns out smaller than the one
measured with the shunt, i.e., the above-mentioned ef-
fects do take place. The values averaged over 3 to 4
measurements (in percentage, 6.5, 2.5 and 1%) give an
idea about the contributions of the current frequency
and the ferromagnetic core to the measurement error of
the effective magnetic field Hm, i.e., eventually, the
electron energy E.
To summarize, the following conclusions recom-
mendations can be suggested:
- electromagnetic scanner for the new accelerator
KUT-20 can operate at long-time operation conditions
at an excitation current I ≅ ± 30A, f = 3 Hz (“saw”);
- for E ≥ 25 MeV, the beam sweep angle will be ϕ
m ≅ ± 12.5°, this corresponding to ∆r ≅ ± 12 cm at the
exit window;
- as preliminary tests show, the homogeneity of the irra-
diation zone meets strict requirements;
- prompt control over the electron energy on the basis of
I exc measurements using the shunt signal in the SEM
(technique used up to the present day) can be employed
up to f ≤ 3 Hz with the energy measurement error
∆ E/E ≤ 1% (towards overestimation);
- to provide the steady-state operation of the scanner at
Iexc ≥± 30 A and E ≥ 25 MeV, the existing “saw” source
must be improved (its power must be raised), or a new
source with I ≥ ± 30 A must be created;
- to improve the accuracy of electron energy measure-
ments, new methods of prompt field strength measure-
ment at operating accelerator conditions must be devel-
oped, as well as the accuracy in determining the beam
coordinate (∆r) at the moment of measurement must be
substantially increased.
The authors are thankful to V.I.Tatanov for his par-
ticipation in test bench measurements.
REFERENCES
1. V.Mitrochenko, V.Krasnogolovets, Yu.Volkolu-
pov, et al. High-Power Electron Linac for Irradia-
tion Applications // Abstracts PAC 2001, June
18-22, 2001. Chicago, USA, p.169.
2. A.N.Dovbnya, A.I.Kosoj, A.E.Tolstoj, V.A.Shend-
rik. The Output Beam Scanning and Forming in the
Multipurpose Electron Accelerators of KIPT //
Problems of Atomic Science and Technology. Is-
sue: Nuclear-Physics Research (28). 1997, v. 1,
p. 114-121. (in Russian).
3. V.N.Boriskin, A.E.Tolstoj, V.L.Uvarov et al. An
automated control of electron energy in technologi-
cal electron linacs // Proc. of XIV Accelerator
Meeting, Protvino, 1994, v. 2, p. 97-98. (in Rus-
sian).
4. A.E.Tolstoj, V.A.Shendrik. Measurements of ELA
energy characteristics with electromagnetic scan-
ning // Proc. of XVII Meeting on Charged Particle
Accelerators. Protvino, 17-20 October, 2000.
p. 55-56. (in Russian).
125
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