Prediction and suppression of two-point 1st order multipacting

Zheng, Zhixue; Facco, A.; Liu, Z.; Popielarski, John; Saito, Kenji; Wei, Junhao; Zhang, Y.

doi:10.1016/j.nima.2013.09.052

Cited by 10 publications

(5 citation statements)

References 4 publications

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“…in which m and e are the mass and electric charge of the electron respectively, B 0 is the approximately uniform magnetic field magnitude near the short plate and K impact is the impact energy of the electron [7,8]. To further interpret K impact in terms of electric and magnetic field, E 0 of the approximately uniform electric field magnitude near the short plate is introduced and the kinetic energy which can be obtained from one time resonant motion by the electron is:…”

Section: Discussionmentioning

confidence: 99%

Multipacting analysis for half wave resonators in the China ADS

Zhang¹,

Zhang²,

He³

et al. 2015

Chinese Phys. C

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Section: Discussionmentioning

confidence: 99%

Multipacting analysis for half wave resonators in the China ADS

Zhang¹,

Zhang²,

He³

et al. 2015

Chinese Phys. C

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“…The new cryomodules with 322 MHz cavities will be assembled with multipactorfree RF couplers as was discussed in ref. [1,2]. Perhaps, the bias Tees will not be required for new cryomodules.…”

Section: Off-line Conditioning Of Sc Cavities In Cryomodule With DC Bmentioning

confidence: 99%

“…The first cryomodule comprising eight superconducting β OPT =0.53 HWRs for the FRIB Linac has been assembled recently and it is undergoing off-line cold and RF testing. The SC cavities have been equipped with original RF couplers [1] shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Suppression of multipacting in high power RF couplers operating with superconducting cavities

Ostroumov

Kazakov

Morris

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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Capacitive input couplers based on a 50  coaxial transmission line are frequently used to transmit RF power to superconducting (SC) resonators operating in CW mode. It is well known that coaxial transmission lines are prone to multipacting phenomenon in a wide range of RF power level and operating frequency. The Facility for Rare Isotope Beams (FRIB) being constructed at Michigan State University includes two types of quarter wave SC resonators (QWR) operating at 80.5 MHz and two types of half wave SC resonators (HWR) operating at 322 MHz. As was reported in ref. [1] a capacitive input coupler used with HWRs was experiencing strong multipacting that resulted in a long conditioning time prior the cavity testing at design levels of accelerating fields. We have developed an insert into 50  coaxial transmission line that provides opportunity to bias the RF coupler antenna and protect the amplifier from the bias potential in the case of breakdown in DC isolation. Two of such devices have been built and are currently used for the off-line testing of 8 HWRs installed in the cryomodule.

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“…It should be noted that geometrical scaling and changing of rf frequency in a coupler can change also the multipacting modes characteristics, thus the probability of developing multipacting during operation and the coupler conditioning time. To solve a similar problem in a 322 MHz, 20 kW coupler scaled from a higher frequency SNS model, an equally sized design based on a λ/4 impedance transformer (called 'multipacting free') was successfully developed and tested [109]. This coupler design could eliminate most of the multipacting levels in the required power range, considerably reducing the conditioning time, and became the new project baseline for the FRIB HWRs (see figure 34).…”

Section: Rf Couplingmentioning

confidence: 99%

Low- to medium-β cavities for heavy ion acceleration

Facco¹

2016

Supercond. Sci. Technol.

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Acceleration of low- and medium-β heavy ions by means of superconducting (SC) linear accelerators (linacs) was made possible by the development, during four decades, of a particular class of cavities characterized by low operation frequency, several different shapes and different electromagnetic modes of operation. Their performance, initially rather poor in operating accelerators, have steadily increased along with the technological progress and nowadays the gap with the high-β, elliptical cavities is close to be filled. Initially confined to a very small number of applications, this family of cavities evolved in many directions becoming one of the most widespread in linacs. Nowadays it is present in the majority of superconducting radio-frequency ion linac projects worldwide. An overview of low- and medium-β SC cavities for heavy ions, focused on their recent evolution and achievements, will be given.

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Prediction and suppression of two-point 1st order multipacting

Cited by 10 publications

References 4 publications

Multipacting analysis for half wave resonators in the China ADS

Multipacting analysis for half wave resonators in the China ADS

Suppression of multipacting in high power RF couplers operating with superconducting cavities

Low- to medium-β cavities for heavy ion acceleration

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