Non-conventional operation modes for millimeter wave relativistic magnetrons

The operation of 8-mm band relativistic magnetrons is considered for traditional and inverted-voltage regimes. The results obtained in a series of experiments are discussed.

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Datum:2016
Hauptverfasser: Gadetsky, N.P., Lebedenko, A.N., Magda, I.I., Shtan’ko, A.A., Volovenko, M.V.
Format: Artikel
Sprache:English
Veröffentlicht: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2016
Schriftenreihe:Вопросы атомной науки и техники
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Online Zugang:https://nasplib.isofts.kiev.ua/handle/123456789/115354
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Zitieren:Non-conventional operation modes for millimeter wave relativistic magnetrons / N.P. Gadetsky, A.N. Lebedenko, I.I. Magda, A.A. Shtan’ko, M.V. Volovenko // Вопросы атомной науки и техники. — 2016. — № 3. — С. 35-37. — Бібліогр.: 3 назв. — англ.

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spelling nasplib_isofts_kiev_ua-123456789-1153542025-02-23T18:12:15Z Non-conventional operation modes for millimeter wave relativistic magnetrons Особенности работы релятивистских магнетронов миллиметрового диапазона в нетрадиционных режимах Особливості роботи релятивістських магнетронів міліметрового діапазону в нетрадиційних режимах Gadetsky, N.P. Lebedenko, A.N. Magda, I.I. Shtan’ko, A.A. Volovenko, M.V. Теория и техника ускорения частиц The operation of 8-mm band relativistic magnetrons is considered for traditional and inverted-voltage regimes. The results obtained in a series of experiments are discussed. Работа посвящена исследованию релятивистских магнетронов 8-мм диапазона в традиционных и инвертированных режимах. Обсуждаются результаты, полученные в серии экспериментов. Робота присвячена дослідженню релятивістських магнетронів 8-мм діапазону в традиційному та інвертованому режимах. Обговорюються результати, отримані в серії експериментів. 2016 Article Non-conventional operation modes for millimeter wave relativistic magnetrons / N.P. Gadetsky, A.N. Lebedenko, I.I. Magda, A.A. Shtan’ko, M.V. Volovenko // Вопросы атомной науки и техники. — 2016. — № 3. — С. 35-37. — Бібліогр.: 3 назв. — англ. 1562-6016 PACS: 52.75.Pv; 52.80.Pi https://nasplib.isofts.kiev.ua/handle/123456789/115354 en Вопросы атомной науки и техники application/pdf Національний науковий центр «Харківський фізико-технічний інститут» НАН України
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
language English
topic Теория и техника ускорения частиц
Теория и техника ускорения частиц
spellingShingle Теория и техника ускорения частиц
Теория и техника ускорения частиц
Gadetsky, N.P.
Lebedenko, A.N.
Magda, I.I.
Shtan’ko, A.A.
Volovenko, M.V.
Non-conventional operation modes for millimeter wave relativistic magnetrons
Вопросы атомной науки и техники
description The operation of 8-mm band relativistic magnetrons is considered for traditional and inverted-voltage regimes. The results obtained in a series of experiments are discussed.
format Article
author Gadetsky, N.P.
Lebedenko, A.N.
Magda, I.I.
Shtan’ko, A.A.
Volovenko, M.V.
author_facet Gadetsky, N.P.
Lebedenko, A.N.
Magda, I.I.
Shtan’ko, A.A.
Volovenko, M.V.
author_sort Gadetsky, N.P.
title Non-conventional operation modes for millimeter wave relativistic magnetrons
title_short Non-conventional operation modes for millimeter wave relativistic magnetrons
title_full Non-conventional operation modes for millimeter wave relativistic magnetrons
title_fullStr Non-conventional operation modes for millimeter wave relativistic magnetrons
title_full_unstemmed Non-conventional operation modes for millimeter wave relativistic magnetrons
title_sort non-conventional operation modes for millimeter wave relativistic magnetrons
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
publishDate 2016
topic_facet Теория и техника ускорения частиц
url https://nasplib.isofts.kiev.ua/handle/123456789/115354
citation_txt Non-conventional operation modes for millimeter wave relativistic magnetrons / N.P. Gadetsky, A.N. Lebedenko, I.I. Magda, A.A. Shtan’ko, M.V. Volovenko // Вопросы атомной науки и техники. — 2016. — № 3. — С. 35-37. — Бібліогр.: 3 назв. — англ.
series Вопросы атомной науки и техники
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last_indexed 2025-11-24T06:13:10Z
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fulltext ISSN 1562-6016. ВАНТ. 2016. №3(103) 35 NON-CONVENTIONAL OPERATION MODES FOR MILLIMETER WAVE RELATIVISTIC MAGNETRONS N.P. Gadetsky, A.N. Lebedenko, I.I. Magda, A.A. Shtan’ko, M.V. Volovenko National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine E-mail: magda@kipt.kharkov.ua The operation of 8-mm band relativistic magnetrons is considered for traditional and inverted-voltage regimes. The results obtained in a series of experiments are discussed. PACS: 52.75.Pv; 52.80.Pi INTRODUCTION The paper is a continuation of our previous studies of millimeter wave relativistic magnetrons (RM) [1, 2]. According to the existing terminological convention, magnetrons are categorized within two principal type groups, 1) conventional devices where electrons are provided either by a thermionic or a secondary-emission cathode, while the anode is united with a slow wave structure (SWS), and 2) inverted magnetrons where the anode block lies inside an annular cathode. We will discuss here millimeter wave RMs which operate in the explosive emission regime, with electric field strengths near the SWS reaching (1…5)·107 V/m. Such electric parameters are unique, in the sense that they enable RM operation both with the ‘properly’ con- nected driving source (the cathode is at a lower potential than the anode block) and with a reverse polarity. In the latter case, it is the SWS that becomes the source of electrons. EXPERIMENT The experiments involved RMs of the two above mentioned configurations, the conventional and the in- verted design. The conventional type was represented by a device with a 48-cavity SWS: the anode and cat- hode of respective diameters dA=22 mm and dc=14 mm; cavity height 1.65 mm, and axial extent Z=6 mm. The operating regimes under study were specified by the range of applied voltages, U0=150 to 320 kV, and mag- netic field strengths Н0= 3 to 11 kOe. The inverted RM possessed a 24 cavity SWS, with dA = 18 mm and dc = 28 mm; cavity height of 0.5 mm, and axial extent of the structure Z=7 mm. The operating modes of RM-24 corresponded to U0 = 150 to 320 kV and H0 = 3 to 11 kOe. In fact, the RM of inverted design could operate at higher magnetic fields. Fig. 1 shows typical waveform records from the conventional RM-48, obtained for a ‘proper’ (panel a) and reverse (panel b) connection of the driving voltage. As seen from the Figure, the length of the microwave pulse (3) was about 20 ns in the case of a ‘properly’ connected driving voltage. With a reversely applied voltage the microwave pulse length increased to 30 ns or more. In Fig. 2 the magnitude of the microwave sig- nal from the conventional magnetron is shown in depen- dence on the magnetic field strength for the cases of ‘proper’ (curve 1) and reverse (curve 2) polarity of the applied voltage. With the reverse polarity the range of microwave generation has diminished by nearly a factor of two. Indeed, the generated frequency lay between 37 and 37.8 GHz in the ‘properly’ connected device and dropped down to 36.7…37 GHz when the applied volt- age was reversed. The radiated power remained practi- cally the same in the both operation modes. a b Fig. 1. Characteristic waveforms of the conventional RM-48 operating with: a – „proper‟ polarity of the driving voltage and b – with a reverse connection. Curve 1 – is the anode voltage; curve 2 – represents total current, and 3 – is the response of a microwave sensor 4 6 8 10 0 100 200 300 400 In te n s it y , a u H 0 , kOe 1 2 Fig. 2. Microwave generation levels of RM-48 with „properly‟ (1), and reversely (2) connected driving voltage mailto:magda@kipt.kharkov.ua ISSN 1562-6016. ВАНТ. 2016. №3(103) 36 a b Fig. 3. Characteristic waveforms of the inverted RМ-24 operating with: а – „proper‟ polarity of the driving voltage and b – with a reverse connection. Curve 1 – is the anode voltage; curve 2 – represents total current, and 3 – is the response of a microwave sensor Similar investigation was carried out with the invert- ed RM. Shown in Fig. 3 are typical oscillograms of the inverted RМ-24 for the cases of proper (panel a), and reversely (panel b) applied driving voltage. As can be seen from the oscillograms, the inverted RM-24 showed practically invariant radiated pulse lengths in all the operation modes under study. Also, it seems worth not- ing that the inverted magnetron, when connected in the reverse manner, demonstrated microwave generation for a ‘proper’ polarity of the driving voltage (i.e. during the second half-wave of the applied pulse). The generated frequency was greater than 42.3 GHz when the device was ‘properly’ connected, and dropped down to 37…37.3 GHz for the reversely applied driving pulse. 2 4 6 8 10 12 0 100 200 300 400 500 2 1 In te n s it y , a u H, kOe Fig. 4. Microwave generation levels of RM-24 with „properly‟ (1), and reversely (2) connected driving voltage Fig. 4 shows microwave intensities from the RM-24 versus applied magnetic field, for the cases of ‘proper’ (curve 1) and reverse (curve 2) polarity of the driving voltage. Similar as with the conventional RM, the range of magnetic field strengths where microwave generation occurs is wider for the ‘proper’ driving polarity. Mean- while, the radiated intensity observable during the se- cond (‘correct’) half-wave of a reversely connected driving voltage happened to be much higher, despite the lower amplitude of that half-wave. Most probably, the effect is due to the greater .emission current during the second half-wave which owes to plasma effects near the cathode. In a number of tests microwave generation of no- ticeable intensity was observed during subsequent half- waves of the driving voltage (that followed the principal one), in ‘correctly’ connected magnetrons of both con- ventional and inverted design. The amplitudes were of comparable size. A typical record for the inverted mag- netron is shown in Fig. 5. Apparently, these anomalies require further investigation. Fig. 5. Characteristic waveforms to describe microwave gen- eration in the inverted RМ-24 with different signs of subsequent half-waves of the driving voltage. Curve 1 – is the anode voltage; curve 2 – represents total current, and 3 – is the response of a microwave sensor CONCLUSIONS Peculiar operation modes of relativistic magnetrons have been studied for the first time, such that are fun- damentally impossible in non-relativistic cross-field devices. Among the results obtained for the convention- al-type relativistic magnetron, note the following. By reversing the polarity of the driving voltage the micro- wave pulse length was increased by almost a factor of two, however the active range of magnetic field strengths diminished. The frequency generated by the magnetron of traditional design varied but slightly both with the classic and reversed polarity of the driving voltage. In the inverted magnetron, the rf pulse length re- mained essentially unchanged with either polarity of the driving voltage. Similar as with the conventional design, the active range of the magnetic field diminished as the applied voltage was reversed in the inverted device. The generation frequency of the inverted magnetron suffered a noticeable change with reversal of the driving voltage, which is in a contrast to the traditional design. Thus, the feasibility of ‘cathode priming’ of the operation mode [3] can be recognized as an unusual function of the SWS when used in the capacity of a cathode. ISSN 1562-6016. ВАНТ. 2016. №3(103) 37 REFERENCES 1. S.A. Berdin, K.V. Chizhov, N.P. Gadetski, V.G. Korenev, A.N. Lebedenko, M.I. Marchenko, I.I. Magda, O.G. Melezhik, V.G. Sinitsin, V.A. Soshenko. Special traits of the millimeter wave relativistic magnetron // Problems of Atomic Science and Tech- nology. Series “Nuclear Physics Investigations”. 2014, № 3, p. 54-59. 2. I.I. Magda, N.P. Gadetski, E.I. Kravtsova, V.D. Naumenko, S.S. Pushkaryov, S.N. Terekhin, A.S. Tischenko. Relativistic magnetron of 8 mm waveband // Problems of Atomic Science and Tech- nology. Series “Plasma Electronics” (6). 2008, № 4, p. 18-20. 3. M.C. Jones, V.B. Neculaes, Y.Y. Lau, R.M. Gilden- bach, W.M. White. Cathode priming of a relativistic magnetron // Applied physics letter. 2004, v. 85, № 26, p. 6332-6334. Article received 29.01.2016 ОСОБЕННОСТИ РАБОТЫ РЕЛЯТИВИСТСКИХ МАГНЕТРОНОВ МИЛЛИМЕТРОВОГО ДИАПАЗОНА В НЕТРАДИЦИОННЫХ РЕЖИМАХ Н.П. Гадецкий, А.Н. Лебеденко, И.И. Магда, А.А. Штанько, H.В. Воловенко Работа посвящена исследованию релятивистских магнетронов 8-мм диапазона в традиционных и инвер- тированных режимах. Обсуждаются результаты, полученные в серии экспериментов. ОСОБЛИВОСТІ РОБОТИ РЕЛЯТИВІСТСЬКИХ МАГНЕТРОНІВ МІЛІМЕТРОВОГО ДІАПАЗОНУ В НЕТРАДИЦІЙНИХ РЕЖИМАХ М.П. Гадецький, О.М. Лебеденко, І.І. Магда, А.О. Штанько, М.В. Воловенко Робота присвячена дослідженню релятивістських магнетронів 8-мм діапазону в традиційному та інверто- ваному режимах. Обговорюються результати, отримані в серії експериментів.