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Author |
Mata, R.; Cros, A.; Gimeno, B.; Raboso, D. |
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Title |
Secondary electron emission yield in thick dielectric materials: a comparison between Kelvin probe and capacitive methods |
Type |
Journal Article |
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Year |
2024 |
Publication |
Journal of Physics D |
Abbreviated Journal |
J. Phys. D |
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Volume |
57 |
Issue |
40 |
Pages |
405302 - 9pp |
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Keywords |
dielectrics; secondary electron emission yield; Multipactor in space devices |
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Abstract |
The recent high demand of secondary electron emission yield (SEY) measurements in dielectric materials from space industry has driven SEY laboratories to improve their facilities and measurement techniques. SEY determination by the common capacitive method, also known as pulsed method, is well accepted and has given satisfactory results in most cases. Nevertheless, the samples under study must be prepared according to the experimental limitations of the technique, i.e. they should be manufactured separated from the devices representing faithfully the surface state of the own device and be as thin as possible. A method based on the Kelvin probe (KP) is proposed here to obtain the SEY characteristics of electrically floating Platinum, Kapton and Teflon placed over dielectric spacers with thicknesses ranging from 1.6 to 12.1 mm. The results are compared with those of the capacitive method and indicate that KP SEY curves are less sensitive to spacer thickness. An explanation based on the literature is also given. In all, we have established that KP is better suited for the analysis of dielectric samples thicker than 3 mm. |
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Address |
[Mata, R.; Gimeno, B.] Ciudad Politecn Innovac, Val Space Consortium, Edificio 8G,Acceso B,Planta B, Valencia 46022, Spain, Email: rafael.mata@uv.es |
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Publisher |
IOP Publishing Ltd |
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English |
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ISSN |
0022-3727 |
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Conference |
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Notes |
WOS:001269188200001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6203 |
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Author |
Gonzalez-Iglesias, D.; Gimeno, B.; Esperante, D.; Martinez-Reviriego, P.; Martin-Luna, P.; Fuster-Martinez, N.; Blanch, C.; Martinez, E.; Menendez, A.; Fuster, J.; Grudiev, A. |
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Title |
Non-resonant ultra-fast multipactor regime in dielectric-assist accelerating structures |
Type |
Journal Article |
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Year |
2024 |
Publication |
Results in Physics |
Abbreviated Journal |
Results Phys. |
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Volume |
56 |
Issue |
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Pages |
107245 - 12pp |
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Keywords |
Multipactor; Dielectric accelerating structures; RF particle accelerators; Plasma discharge |
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Abstract |
The objective of this work is the evaluation of the risk of suffering a multipactor discharge in an S-band dielectric-assist accelerating (DAA) structure for a compact low-energy linear particle accelerator dedicated to hadrontherapy treatments. A DAA structure consists of ultra-low loss dielectric cylinders and disks with irises which are periodically arranged in a metallic enclosure, with the advantage of having an extremely high quality factor and very high shunt impedance at room temperature, and it is therefore proposed as a potential alternative to conventional disk-loaded copper structures. However, it has been observed that these structures suffer from multipactor discharges. In fact, multipactor is one of the main problems of these devices, as it limits the maximum accelerating gradient. Because of this, the analysis of multipactor risk in the early design steps of DAA cavities is crucial to ensure the correct performance of the device after fabrication. In this paper, we present a comprehensive and detailed study of multipactor in our DAA design through numerical simulations performed with an in-house developed code based on the Monte-Carlo method. The phenomenology of the multipactor (resonant electron trajectories, electron flight time between impacts, etc.) is described in detail for different values of the accelerating gradient. It has been found that in these structures an ultra-fast non-resonant multipactor appears, which is different from the types of multipactor theoretically studied in the scientific literature. In addition, the effect of several low electron emission coatings on the multipactor threshold is investigated. Furthermore, a novel design based on the modification of the DAA cell geometry for multipactor mitigation is introduced, which shows a significant increase in the accelerating gradient handling capabilities of our prototype. |
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Address |
[Gonzalez-Iglesias, Daniel; Gimeno, Benito; Esperante, Daniel; Martinez-Reviriego, Pablo; Martin-Luna, Pablo; Fuster-Martinez, Nuria; Blanch, Cesar; Martinez, Eduardo; Menendez, Abraham; Fuster, Juan] CSIC UV, Inst Fis Corpuscular IF, c Catedrat Jose Beltran 2, Paterna 46980, Spain, Email: daniel.gonzalez-iglesias@uv.es |
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Publisher |
Elsevier |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2211-3797 |
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Expedition |
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Conference |
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Notes |
WOS:001133850600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5866 |
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Permanent link to this record |
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Author |
Zhang, X.; Xiao, Y.T.; Gimeno, B. |
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Title |
Multipactor Suppression by a Resonant Static Magnetic Field on a Dielectric Surface |
Type |
Journal Article |
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Year |
2020 |
Publication |
IEEE Transactions on Electron Devices |
Abbreviated Journal |
IEEE Trans. Electron Devices |
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Volume |
67 |
Issue |
12 |
Pages |
5723-5728 |
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Keywords |
Radio frequency; Dielectrics; Magnetic resonance; Discharges (electric); Surface discharges; Surface waves; Electrostatics; Monte Carlo simulation; multipactor discharge; orthogonal waves; resonant static magnetic field; secondary electron yield |
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Abstract |
In this article, we study the suppression of the multipactor phenomenon on a dielectric surface by a resonant static magnetic field. A homemade Monte Carlo algorithm is developed for multipactor simulations on a dielectric surface driven by two orthogonal radio frequency (RF) electric field components. When the static magnetic field is perpendicular to the tangential and normal RF electric fields, it is shown that if the normal electric field lags the tangential electric field by pi/2, the superposition of the normal and tangential electric fields will trigger a gyro-acceleration of the electron cloud and restrain the multipactor discharge effectively. By contrast, when the normal electric field is in advance of the tangential electric field by pi/2, the difference between the normal and tangential electric fields drives gyro-motion of the electron cloud. Consequently, two enhanced discharge zones are inevitable. The suppression effects of the resonant static magnetic field that is parallel to the tangential RF electric field or to the normal RF electric field are also presented. |
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Address |
[Zhang, Xue; Xiao, Yuting] Xiangtan Univ, Sch Automat & Elect Informat, Xiangtan 411105, Hunan, Peoples R China, Email: zhangxue.iecas@yahoo.com; |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9383 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000594337700064 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4627 |
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Permanent link to this record |
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Author |
Monerris-Belda, O.; Cervera Marin, R.; Rodriguez Jodar, M.; Diaz-Caballero, E.; Alcaide Guillen, C.; Petit, J.; Boria, V.E.; Gimeno, B.; Raboso, D. |
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Title |
High Power RF Discharge Detection Technique Based on the In-Phase and Quadrature Signals |
Type |
Journal Article |
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Year |
2021 |
Publication |
IEEE Transactions on Microwave Theory and Techniques |
Abbreviated Journal |
IEEE Trans. Microw. Theory Tech. |
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Volume |
69 |
Issue |
12 |
Pages |
5429-5438 |
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Keywords |
Radio frequency; Microwave theory and techniques; Electric breakdown; Discharges (electric); Noise measurement; Sensitivity; RF signals; Corona; microwave devices; multipactor; radio frequency (RF) breakdown; RF high power |
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Abstract |
High power radio frequency (RF) breakdown testing is a subject of great relevance in the space industry, due to the increasing need of higher transmission power and smaller devices. This work presents a novel RF breakdown detection system, which monitors the same parameters as the microwave nulling system but with several advantages. Where microwave nulling-a de facto standard in RF breakdown testing-is narrowband and requires continuous tuning to keep its sensitivity, the proposed technique is broadband and maintains its performance for any RF signal. On top of that, defining the detection threshold is cumbersome due to the lack of an international standardized criterion. Small responses may appear in the detection system during the test and, sometimes, it is not possible to determine if these are an actual RF breakdown or random noise. This new detection system uses a larger analysis bandwidth, thus reducing the cases in which a small response is difficult to be classified. The proposed detection method represents a major step forward in high power testing as it runs without human intervention, warning the operator or decreasing the RF power automatically much faster than any human operator. |
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Address |
[Monerris-Belda, Oscar; Cervera Marin, Raul; Rodriguez Jodar, Miguel; Petit, John] Val Space Consortium, Valencia 46022, Spain, Email: oscar.monerris@val-space.com |
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Corporate Author |
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Thesis |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9480 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000725804500027 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5042 |
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Permanent link to this record |
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Author |
Zhang, X.; Chang, C.; Gimeno, B. |
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Title |
Multipactor Analysis in Circular Waveguides Excited by TM01 Mode |
Type |
Journal Article |
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Year |
2019 |
Publication |
IEEE Transactions on Electron Devices |
Abbreviated Journal |
IEEE Trans. Electron Devices |
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Volume |
66 |
Issue |
11 |
Pages |
4943-4951 |
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Keywords |
Circular waveguide; multipactor; ponderomotive force; TM01 mode |
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Abstract |
A series of detailed numerical simulations are used to investigate the properties ofmultipactor breakdown in circularwaveguidespropagating the TM01 mode. AMonte Carlo model is constructed to track the motion of the electrons, study the multipactor scenarios, and predict the multipactor thresholds. The theoretical and numerical analyses indicate that the product of the frequency and the gap (f . D) affects both the intensity of the ponderomotive force and its spatial distribution, which results from the nonuniformity of the radio frequency (RF) field and significantly influences the electrons' trajectoriesandmultipactor trends. The decrease in f . D results in a remarkable enhancement in the magnitude of the ponderomotive force, while the maximal intensity gradually moves toward the half radius R/2 area. Low values of f . D correspond to high ponderomotive potential, which sustains the short-range electrons and triggers the single-sidedmultipactor. In contrast, high values of f . D correspond to low ponderomotive potential, contributing to long-range electrons and exciting the double-sided multipactor. Fitting to the susceptibility diagram produces the border line and a modified f . D threshold of (f . D) th approximate to 338.4 GHz mm, which separates the susceptibility diagram into single-sided, double-sided, andmixed-sided zones. The initial electron energy influences their trajectories at high f . D and low RF power. This effect tends to dominate the multipactor behavior in the mixed-sided region. |
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Address |
[Zhang, Xue] Xiangtan Univ, Coll Informat Engn, Xiangtan 411105, Hunan, Peoples R China, Email: zhangxue.iecas@yahoo.com; |
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Corporate Author |
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Thesis |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9383 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000494419900066 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4191 |
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Permanent link to this record |