Measurement of distribution function of REB, used in collective ion accelerator

The parameters of the intense relativistic electron beam (REB), being a base element of the ion accelerator concept, were measured at the exit of the first section of a collective ion accelerator. The experimental studies of a REB current passing through metal foils of a different thickness were c...

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Опубліковано в: :Вопросы атомной науки и техники
Дата:2004
Автори: Chupikov, P.T., Medvedev, D.V., Onishchenko, I.N., Panasenko, B.D., Prokopenko, Yu.V., Pushkarev, S.S.
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Опубліковано: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2004
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Цитувати:Measurement of distribution function of REB, used in collective ion accelerator / P.T. Chupikov, D.V. Medvedev, I.N. Onishchenko, B.D. Panasenko, Yu.V. Prokopenko, S.S. Pushkarev // Вопросы атомной науки и техники. — 2004. — № 1. — С. 38-40. — Бібліогр.: 6 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-78481
record_format dspace
spelling Chupikov, P.T.
Medvedev, D.V.
Onishchenko, I.N.
Panasenko, B.D.
Prokopenko, Yu.V.
Pushkarev, S.S.
2015-03-18T14:12:46Z
2015-03-18T14:12:46Z
2004
Measurement of distribution function of REB, used in collective ion accelerator / P.T. Chupikov, D.V. Medvedev, I.N. Onishchenko, B.D. Panasenko, Yu.V. Prokopenko, S.S. Pushkarev // Вопросы атомной науки и техники. — 2004. — № 1. — С. 38-40. — Бібліогр.: 6 назв. — англ.
1562-6016
PACS: 29.27.-a
https://nasplib.isofts.kiev.ua/handle/123456789/78481
The parameters of the intense relativistic electron beam (REB), being a base element of the ion accelerator concept, were measured at the exit of the first section of a collective ion accelerator. The experimental studies of a REB current passing through metal foils of a different thickness were carried out. Using the obtained dependence of beam current attenuation on the foil thickness and the calibration curves (tables) of the dependence of penetration lengths on the particle energy, the energy distribution function of REB electrons was determined and it is represented as a histogram. The kind of plasma resulting in a short circuit of the magnetically-insulated diode was determined.
В першій секції двохсекційного колективного прискорювача іонів проведені вимірювання параметрів сильнострумового релятивістського електронного пучка (РЕП), який є головним елементом концепції прискорення іонів. Проведені експериментальні дослідження проходження струму РЕП через металевіфольги різної товщини. По отриманій залежності ослаблення струму пучка від товщини фольги і каліброваним кривим (таблицям) залежності довжини гальмування від енергії часток, виявлена функція розподілу електронів РЕП по енергії в вигляді гістограми. Вияснений вид плазми, яка приводить до закорачення магнітно-ізольованого діода.
В первой секции двухсекционного коллективного ускорителя ионов проведены измерения параметров сильноточного релятивистского электронного пучка (РЭП), являющегося главным элементом концепции ускорителя ионов. Проведены экспериментальные исследования прохождения тока РЭП через металлические фольги различной толщины. По полученной зависимости ослабления тока пучка от толщины фольги и калибровочных кривых (таблиц) зависимости длин торможения от энергии частиц, определена функция распределения электронов РЭП по энергии в виде гистограммы. Определен вид плазмы, приводящей к закорачиванию магнитно-изолированного диода.
This work was supported by STCU (project № 1569).
en
Національний науковий центр «Харківський фізико-технічний інститут» НАН України
Вопросы атомной науки и техники
Сильноточные импульсные ускорители
Measurement of distribution function of REB, used in collective ion accelerator
Вимірювання функції розподілу РЕП, який використовується в колективному прискорювачі іонів
Измерение функции распределения РЭП, используемого в коллективном ускорителе ионов
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Measurement of distribution function of REB, used in collective ion accelerator
spellingShingle Measurement of distribution function of REB, used in collective ion accelerator
Chupikov, P.T.
Medvedev, D.V.
Onishchenko, I.N.
Panasenko, B.D.
Prokopenko, Yu.V.
Pushkarev, S.S.
Сильноточные импульсные ускорители
title_short Measurement of distribution function of REB, used in collective ion accelerator
title_full Measurement of distribution function of REB, used in collective ion accelerator
title_fullStr Measurement of distribution function of REB, used in collective ion accelerator
title_full_unstemmed Measurement of distribution function of REB, used in collective ion accelerator
title_sort measurement of distribution function of reb, used in collective ion accelerator
author Chupikov, P.T.
Medvedev, D.V.
Onishchenko, I.N.
Panasenko, B.D.
Prokopenko, Yu.V.
Pushkarev, S.S.
author_facet Chupikov, P.T.
Medvedev, D.V.
Onishchenko, I.N.
Panasenko, B.D.
Prokopenko, Yu.V.
Pushkarev, S.S.
topic Сильноточные импульсные ускорители
topic_facet Сильноточные импульсные ускорители
publishDate 2004
language English
container_title Вопросы атомной науки и техники
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
format Article
title_alt Вимірювання функції розподілу РЕП, який використовується в колективному прискорювачі іонів
Измерение функции распределения РЭП, используемого в коллективном ускорителе ионов
description The parameters of the intense relativistic electron beam (REB), being a base element of the ion accelerator concept, were measured at the exit of the first section of a collective ion accelerator. The experimental studies of a REB current passing through metal foils of a different thickness were carried out. Using the obtained dependence of beam current attenuation on the foil thickness and the calibration curves (tables) of the dependence of penetration lengths on the particle energy, the energy distribution function of REB electrons was determined and it is represented as a histogram. The kind of plasma resulting in a short circuit of the magnetically-insulated diode was determined. В першій секції двохсекційного колективного прискорювача іонів проведені вимірювання параметрів сильнострумового релятивістського електронного пучка (РЕП), який є головним елементом концепції прискорення іонів. Проведені експериментальні дослідження проходження струму РЕП через металевіфольги різної товщини. По отриманій залежності ослаблення струму пучка від товщини фольги і каліброваним кривим (таблицям) залежності довжини гальмування від енергії часток, виявлена функція розподілу електронів РЕП по енергії в вигляді гістограми. Вияснений вид плазми, яка приводить до закорачення магнітно-ізольованого діода. В первой секции двухсекционного коллективного ускорителя ионов проведены измерения параметров сильноточного релятивистского электронного пучка (РЭП), являющегося главным элементом концепции ускорителя ионов. Проведены экспериментальные исследования прохождения тока РЭП через металлические фольги различной толщины. По полученной зависимости ослабления тока пучка от толщины фольги и калибровочных кривых (таблиц) зависимости длин торможения от энергии частиц, определена функция распределения электронов РЭП по энергии в виде гистограммы. Определен вид плазмы, приводящей к закорачиванию магнитно-изолированного диода.
issn 1562-6016
url https://nasplib.isofts.kiev.ua/handle/123456789/78481
citation_txt Measurement of distribution function of REB, used in collective ion accelerator / P.T. Chupikov, D.V. Medvedev, I.N. Onishchenko, B.D. Panasenko, Yu.V. Prokopenko, S.S. Pushkarev // Вопросы атомной науки и техники. — 2004. — № 1. — С. 38-40. — Бібліогр.: 6 назв. — англ.
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first_indexed 2025-11-27T08:20:45Z
last_indexed 2025-11-27T08:20:45Z
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fulltext MEASUREMENT OF DISTRIBUTION FUNCTION OF REB, USED IN COLLECTIVE ION ACCELERATOR P.T. Chupikov, D.V. Medvedev, I.N. Onishchenko, B.D. Panasenko, Yu.V. Prokopenko, S.S. Pushkarev NSC KIPT, 1, Akademicheskaya st., Kharkov, 61108, Ukraine; E-mail: onish@kipt.kharkov.ua The parameters of the intense relativistic electron beam (REB), being a base element of the ion accelerator concept, were measured at the exit of the first section of a collective ion accelerator. The experimental studies of a REB current passing through metal foils of a different thickness were carried out. Using the obtained dependence of beam current atten- uation on the foil thickness and the calibration curves (tables) of the dependence of penetration lengths on the particle en- ergy, the energy distribution function of REB electrons was determined and it is represented as a histogram. The kind of plasma resulting in a short circuit of the magnetically-insulated diode was determined. PACS: 29.27.-a The purpose of investigations is the determination of the energy distribution function of electrons of REB used in the collective ion accelerator. It was made by measuring the REB current decreasing with metal foil thickness increasing. Along with cutting off the plasma from REB by means of metal foils we clarified the ori- gin of plasma that carried out a short circuit of magneti- cally-insulated diode and caused a long duration signal of the electron current observed at the collector. 1. DETERMINATION OF PLASMA ORIGIN In the course of the REB current registration by means of the Faraday cup (FC) and Rogovsky coil a negative unidirectional signal of long duration ≈τ 5 µs (tail) is observed. Its duration considerably exceeds the time of a short circuit of the anode-cathode gap rated by the plasma extension velocity Tv =(2…5)·106 cm/s [1] and value of gap d =11 mm and, therefore, it is much more than the pulse duration of REB. On this time inter- val the oscillogram of a current from the Marx generator through the short circuitited diode looks like a damped sinusoid unlike the unidirectional signal from FC (Fig.1,a). It means that the signal from FC has not rela- tion with circuit currents of the Marx generator. For ex- planation of such a signal, the hypothesis about pres- ence of plasma in the REB drift liner is natural. This plasma causes the negative FC signal corresponding to the electron current SenvI T= with thermal velocity Tv . Here n is the plasma density, S is the receiving square of FC. For available plasma parameters ( n ≈ 1013 cm-3) and FC (diameter 4.5 cm) the electron FC current is I ≈3 kA that is comparable to the REB cur- rent and corresponds to the amplitude of the tail of sig- nal. In addition to the plasma with a density dn that is formed at a breakdown of the diode gap and propagates freely along the external magnetic field, the plasma with a density gn can be generated because of poor vacuum at ionization of residual gas by REB. With the purpose for cutting off the plasma from REB and receiving of the FC signal corresponding only to the REB current the aluminum foils were used. To determine which of the indicated plasmas is present in the plant and forms the FC signal, the foils were placed in different places: immediately after the diode (for overlapping only the diode plasma nd) or at the end of drift channel before FC (for cutting off both the diode plasma dn and the plasma of the ionized gas gn ). -1,0µ 0,0 1,0µ 2,0µ 3,0µ 4,0µ -4 -2 0 2 4 2 1 B  1 2 3 5 4 C ur re nt , k A Time, s a - 8 µm foil at the exit of the chamber -1,0µ 0,0 1,0µ 2,0µ 3,0µ 4,0µ -4 -2 0 2 4 2 1 B  1 2 3 5 4 C ur re nt , k A Time, s b - 40 µm foil at the entrance of the chamber Fig.1. The oscillograms of the input current of the magnetically-isolated diode (1) and the current of the electron beam on the Faraday cup passing through the foil (2). The denotations on the trans- porting scheme of electron flow: 1 - cathode; 2 - anode; 3 - foil; 4 – electron beam; 5 - Faraday cup In addition for definition of the presence and role of the plasma of ionized gas we have made experiments with finer vacuum obtained using the trap with liquid nitrogen. The coincidence of results for poor and fine vacuum demonstrated the absence of the plasma of ion- ized residual gas. When realizing these experiments it turned out that the foils being evaporated and ionized by REB generate ___________________________________________________________ PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1. Series: Nuclear Physics Investigations (42), p.38-40.38 mailto:onish@kipt.kharkov.ua the plasma with a density fn and cause the FC signal- tail. This phenomenon depends on the foil thickness and REB energy. The outbreak of plasma is not also exclud- ed if the time of foil combustion is not enough. In view of mentioned considerations, a series of ex- periments was made for explanation of the origin of the signal-tail on FC and the problem – which plasma of considered ones is responsible for such kind of signal? The experiments performed and shown in Fig.1 repre- senting the diode current (1) and FC current (2) in de- pendence on the foil location (at entrance and at exit of the drift tube or at both places simultaneously) and its thickness (8 and 40 µm), are gathered in the Table. In the Table the results of the experiment taken from Fig.1 are given together with answers: i) is or is not there the signal-tail, and ii) logical conclusion about the presence and role of corresponding plasma. N um be r o f ex pe rim en t Fo il th ic kn es s, µm Place of foil (be- fore or af- ter drift liner) Experiment result. Is there a signal tail? (Yes or No) Po ss ib le p la sm a C on cl us io n 1 8 before Yes gn , fn fn 2 8 after Yes fn fn 3 8+8 before and after Yes fn fn 4 40 before No gn , fn none 5 40 after Yes fn fn 6 40+40 before and after No fn none 7 40+8 before and after Yes fn fn As it follows from the Table and taking into account that the high vacuum has eliminated the presence of gn , in experiment №1 from two possible kinds of plasmas ( gn and fn ), it is necessary to conclude that the signal- tail is caused by only foil plasma with fn density. In experiment №2 the signal-tail on FC is caused by only foil plasma ( fn ). From experiment №3 it follows that the plasma of the evaporated and ionized foil ( fn ) is only responsible for the tail of a signal on FC, and oth- ers are separated. And two foils have noticeably attenu- ated the REB current. In experiments №4 and 6 the foil thick of 40 µm in thick (or two thin ones) cuts off the plasmas with a density of dn and gn and does not pro- duce a foil plasma ( fn ). In these cases, the REB cur- rent is noticeably decreased that is naturally. In experi- ment №5 with the thick foil after the drift tube the ob- servable signal-tail is probably caused by the plasma with fn density in the case of sputtering the thick foil by REB which is not decelerated, as it takes place in ex- periment №6. In experiment №4 unlike №5 the foil is at a large distance from FC and the foil plasma ( fn ) reaches FC with a large delay that is not registered at a working scan of the oscilloscope. And at last, in experi- ment №7 the foil plasma ( fn ) arises since the second foil is thin as compared with experiment № 6. It should be noted that in experiments № 4 and 6 the duration of the collector current pulse corresponded to the duration of the REB pulse that was confirmed by measurements of X-radiation. Summarizing the analysis performed it is possible to conclude that in all versions the foils either the signal- tail is eliminated, or such a signal is produce only by the foil plasma with fn density. Thus, as the plasma of ionized residual gas is absent that is shown in experi- ments with the high vacuum, it is possible to declare that at the absence of foils the signal-tail on FC is caused only by the diode plasma with dn density. 2. ENERGY DISTRIBUTION FUNCTION OF RELATIVISTIC ELECTRON BEAM The experimental studies with using the aluminum foils allowed us to determine the electron energy distri- bution function of REB. The method basing on attenua- tion of the electron flow by metal foils of a different thickness was used for this purpose [2]. According to the technique introduced in paper [2] the current value jI of REB, registered by the Faraday cup after REB passing the foil with a thickness ρσδ /jj = , where jσ is normalized foil thickness in g/cm2 and ρ is the foil density in g/cm3, is determined by the expression ∑ = == n i iijij njEKII 1 0 ,...,1),(ϕ . (1) Here n is the number of foils with different thick- ness jδ ; 0I is the electron beam current at the en- trance in the foil; )( ii Eϕ is the value of a distri- bution function of electrons with energy ],[ 1 iii EEE −∈ . An energy interval ],0[ 0E under consideration, where 0E is the upper bound of the energy interval of REB (in our experiments it is de- termined by the maximum value of voltage between the cathode and anode), is divided on equal inter- vals n so the energy width of each interval is equal to nEEEE ii /01 =−=∆ − . The value of nEiEi 2/)12( 0−= is the energy in the middle of i - th interval. The jiK factors are determined as EERKK ijji ∆≈ ))(/(δ , where ))(/( ij ERK δ is the transmission factor of elec- ___________________________________________________________ PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1. Series: Nuclear Physics Investigations (42), p.38-40.39 trons with iE energy that passed through the foil with jδ thickness. The transmission factor is deter- mined from the universal curve for relativistic elec- trons passed through aluminum [2, 3]. The )( iER is the penetration depth of electrons with iE energy in aluminum media (up to total absorption) that is determined by the formula [2, 4] )]83.31/(9878.01[661.0)( iii EEER +−= or by the tables of [5]. The values of )( ii Eϕ are the solution of the system of simple equations (1). The energy distribution function of electrons )(Eϕ is represented as the histogram )( ii Eϕ . In our experiments 0I =4.4 kA and maximum volt- age value between the cathode and anode of the acceler- ator was equal to 280 kV. In Fig. 2 the experimental dependence of electron current passed through an aluminum foil upon nor- malized foil thickness ( jσ ) is shown. The experi- mental points are corresponding to maximum val- ues of the pulsed electron beam current on the Fara- day cup. 0 50 100 150 200 250 1,0 1,5 2,0 2,5 3,0 3,5 C ur re nt , k A Normalized foil thickness (σ )*104, g/cm2 Fig. 2 Experimental collector current dependence upon foil thickness Using measured currents of electron beam passed through foils of different thickness and above men- tioned technique the energy distribution function of electrons was determined that is shown as a histogram in Fig.3. It is seen that almost 50% of electrons has a value of (210±30) keV. Energy of the main quantity of electrons is distributed within 60...240 keV. 0 50 100 150 200 250 300 0,0 0,1 0,2 0,3 0,4 0,5 0,6 E ne rg y di st ri bu tio n fu nc tio n Energy, keV Fig.3 The histogram of electron en- ergy distribution Thus, the technique for measuring the energy distri- bution function of relativistic electrons based on passing REB through aluminum foils of different thickness was perfected. In our experiment, the measurements of the REB energy distribution function by this technique are satisfactorily coincident with the earlier obtained results based on determination of the voltage on the diode [6]. This work was supported by STCU (project № 1569). REFERENCES 1. Yu.V.Tkach., Ya.B.Fainberg, N.P.Gadetskiy et al.// Pribori i technika ehksperimenta. 1976, № 2, p.129. (in Russian) 2. A.V.Azharenkov, V.T.Astrelin, V.P.Dragunov // Preprint INP, AS USSR. 1977, 21 p. (in Russian). 3. H.H. Seliger // Phys. Rev. 1955, v.100, p.1029. 4. K.H. Weber // Nucl. Meth. 1964, v.25, p.261. 5. A.P.Komarov, S.P.Kruglov, I.V.Lopatin. Measure- ment of total energy of beams of Bremsstrahlung from electron accelerators. L.: “Nauka”, 1972 (in Russian). 6. P.T.Chupikov, D.V.Medvedev, I.N.Onishchenko, et al. // Problems of Atomic Science and Technology. Series: Plasma Physics (7). 2002, № 4, p.132. ИЗМЕРЕНИЕ ФУНКЦИИ РАСПРЕДЕЛЕНИЯ РЭП, ИСПОЛЬЗУЕМОГО В КОЛЛЕКТИВНОМ УСКОРИТЕЛЕ ИОНОВ П.Т. Чупиков, Д.В. Медведев, И.Н. Онищенко, Б.Д. Панасенко, Ю.В. Прокопенко, С.С. Пушкарев В первой секции двухсекционного коллективного ускорителя ионов проведены измерения параметров сильноточного релятивистского электронного пучка (РЭП), являющегося главным элементом концепции ускорителя ионов. Проведены экспериментальные исследования прохождения тока РЭП через металличе- ские фольги различной толщины. По полученной зависимости ослабления тока пучка от толщины фольги и калибровочных кривых (таблиц) зависимости длин торможения от энергии частиц, определена функция рас- пределения электронов РЭП по энергии в виде гистограммы. Определен вид плазмы, приводящей к закора- чиванию магнитно-изолированного диода. ВИМІРЮВАННЯ ФУНКЦІЇ РОЗПОДІЛУ РЕП, ЯКИЙ ВИКОРИСТОВУЄТЬСЯ В КОЛЕКТИВНОМУ ПРИСКОРЮВАЧІ ІОНІВ П.Т. Чупіков, Д.В. Медведєв, І.М. Оніщенко, Б.Д. Панасенко, Ю.В. Прокопенко, С.С. Пушкарьов В першій секції двохсекційного колективного прискорювача іонів проведені вимірювання параметрів сильнострумового релятивістського електронного пучка (РЕП), який є головним елементом концепції прискорення іонів. Проведені експериментальні дослідження проходження струму РЕП через металеві 40 фольги різної товщини. По отриманій залежності ослаблення струму пучка від товщини фольги і каліброваним кривим (таблицям) залежності довжини гальмування від енергії часток, виявлена функція розподілу електронів РЕП по енергії в вигляді гістограми. Вияснений вид плазми, яка приводить до закорачення магнітно-ізольованого діода. ___________________________________________________________ PROBLEMS OF ATOMIC SIENCE AND TECHNOLOGY. 2004. № 1. Series: Nuclear Physics Investigations (42), p.38-40.41 ВИМІРЮВАННЯ ФУНКЦІЇ РОЗПОДІЛУ РЕП, ЯКИЙ ВИКОРИСТОВУЄТЬСЯ В КОЛЕКТИВНОМУ ПРИСКОРЮВАЧІ ІОНІВ П.Т. Чупіков, Д.В. Медведєв, І.М. Оніщенко, Б.Д. Панасенко, Ю.В. Прокопенко, С.С. Пушкарьов