arXiv subjects

Ilan Ben-Zvi

Publications and source records attributed to Ilan Ben-Zvi.

15 recordsLinked to original sources

arXiv2026

Design Study of an Endless RF Phase Shifter Using Ferroelectric Capacitors

An endless radio-frequency (RF) phase shifter is designed using ferroelectric capacitors. An endless phase winds continuously and without bound while every control voltage executes a bounded periodic cycle. A new scheme for an endless RF phase shifter is proposed and studied in the framework of an equivalent circuit. Besides the endless property, this phase shifter offers an exceptionally low insertion-loss, high-speed and high-power capability. The device may perform as an exact frequency translator whose offset is locked to the bias repetition frequency. Optimized realizations are given at 400 and 800 MHz with full conductor-loss accounting: 0.19 and 0.28 dB average insertion loss. A phase advance rate of a few microseconds per turn is limited only by the bias electronics, and power capability on the order of 100 kW may be achieved through stacked-wafer construction. An instantaneous bandwidth of approximately 2.5% is loss-limited rather than mechanism-limited. The design surpasses the best endless phase shifter in the literature, the rotary-field ferrite device, in speed, loss, and power, and improves on the serrodyne ferroelectric frequency translator in efficiency and drive electronics requirements.

physics.acc-ph↗

arXiv2025

Design of a High-Average-Power Ferroelectric Phase Shifter

This paper describes performance of a voltage controlled phase shifter designed for a high average power and a high figure of merit. The device is a reflection-type, resonant phase shifter that utilizes ferroelectric capacitors and impedance matching to the port impedance. With state-of-the-art ferroelectric materials, the device achieves a high Figure of Merit of nearly a thousand degrees phase shift per dB insertion loss at 800 MHz, along with sub-microsecond response. This phase shifter is capable of handling average power up to a megawatt. Its application is expected to enhance the electrical efficiency of particle accelerators, reducing both capital and operating costs.

physics.acc-ph↗

arXiv2025

Design of a Fast Reactive Tuner for 1.3 GHz TESLA cavities at MESA

This work presents a state-of-the-art design of a Ferroelectric Fast Reactive Tuner (FE-FRT), capable of modulating high reactive power in TESLA type cavities on a microsecond time scale. The Mainz Energy-Recovering Superconducting Accelerator employs superconducting radio frequency cavities operating at 1.3 GHz, achieving quality factors on the order of $10^{10}$. However, detuning of $\pm$25 Hz induced by microphonics have led to the use of strong coupling for the fundamental power coupler, requiring high-power amplifiers, orders of magnitude above the intrinsic dissipation. Current solutions to mitigate microphonics rely on piezoelectric tuners, which are not fast enough for the spectral range of the microphonics. A novel alternative is the FE-FRT, a technology made possible by the development of low-loss ferroelectric materials, which offer sub-microsecond response times. Analytical results are provided along with their validation through finite-element simulations. The FE-FRT is expected to handle substantial reactive power while offering a tuning range of 50 Hz in these type of cavities, resulting in a reduction in peak forward RF power by about an order of magnitude.

physics.acc-ph↗

arXiv2025

Detailed Design and Optimization of Ferro-Electric Tuners

A detailed, step-by-step design methodology of a Ferroelectric Fast Reactive Tuner (FE-FRT) capable of modulating Mega VAR reactive powers on a sub-microsecond time scale is given. Closed expressions of values for all the components of the tuner are detailed, and tuner performance optimization is addressed, resulting in a Figure of Merit measure of FE-FRT tuner performance and use case applicability over a wide range of RF frequencies and reactive power levels. This enables addressing feasibility and rapid assessment of design parameters given an FE-FRT tuning scenario defined by required tuning range, cavity operating frequency a cavity stored energy.

physics.acc-ph↗

arXiv2025

High Power Fast Frequency Modulation

A fast and highly efficient frequency modulation at a high power level is described. The system incorporates ferroelectric phase shifters and a magic-T or a circulator. A magnetron may be considered as a potential application. The magnetron output may be converted to a selected reference frequency with negligible insertion loss. The method also allows simultaneous amplitude and phase control.

physics.acc-ph↗

arXiv2025

Magnetron Stabilization using Frequency Modulation

An unstable magnetron RF source for driving an accelerator cavity at high power is stabilized using ferroelectric fast reactive tuning. The magnetron output is converted to a selected reference frequency with negligible insertion loss. The conversion is achieved by modulating the magnetron's frequency, such that the modulation converts the magnetron's output to the exact reference frequency. The method also allows simultaneous amplitude and phase control.

physics.acc-ph↗

arXiv2021

Lasing in 15 atm CO2 cell optically pumped by a Fe:ZnSe laser

10 μm lasing is studied in a compact CO2-He cell pressurized up to 15 atm when optically pumped by a ~50 mJ Fe:ZnSe laser tunable around 4.3 μm. The optimal pump wavelength and partial pressure of CO2 for generating 10 μm pulses are found to be ~4.4 μm and 0.75 atm, respectively. Without cavity optimization, the optical-to-optical conversion efficiency reached ~10% at a total pressure of 7 atm. The gain lifetime is measured to be ~1 μs at pressures above 10 atm, indicating the feasibility of using high-pressure optically pumped CO2 for the efficient amplification of picosecond 10 μm pulses.

physics.optics↗

arXiv2021

High-Power Ferro-Electric Fast Reactive Tuner

We present a novel design of a FerroElectric Fast Reactive Tuner (FE-FRT) capable of modulating Mega VAR reactive power on a sub-microsecond time scale. We show detailed analytical estimates of the performance of this device and benchmark these estimates against finite element method eigenmode and frequency domain electromagnetic simulations.

physics.acc-ph↗

arXiv2021

Resonant noninear refraction of 4-5 $μ$m light in CO and CO$_2$ gas

The resonant nonlinear refraction of 4-5 $μ$m light in CO and CO$_2$ gas at a peak intensity of 15 MW/cm$^2$ was demonstrated using time- and frequency-resolved measurements of self-focusing and self-defocusing. The nonlinearity of these molecular gases exhibits intensity-dependent sign reversals and a < 4 ns response time. A change from self-focusing to self-defocusing or vice-versa was observed to occur for Rabi frequencies that are comparable to the collisional linewidth. A density matrix model for the nonlinear susceptibility of a strongly driven two-level system provides a qualitative explanation for these results.

physics.optics↗

arXiv2020

Demonstration of Planar Ultrananocrystalline Diamond Field Emission Source Operating in SRF Injector at 2 Kelvin

Reported here is the first demonstration of electron beam generation in an SRF TESLA 1.3 GHz gun equipped with field emission cathode when operated at 2 Kelvin. The cathode is submicron film of nitrogen-incorporated ultrananocrystalline diamond [(N)UNCD] deposited atop a Nb RRR300 cathode plug. The output current was measured to increase exponentially as a function of the cavity gradient. Our results demonstrate a feasible path toward simplified fully cryogenic SRF injector technology. One important finding is that the electron emitter made of (N)UNCD, a material long been known as a highly efficient field emission material, demonstrated a record low turn-on gradient of 0.6 MV/m. A hypothesis explaining this behavior is proposed.

physics.acc-ph↗

arXiv2019

Increasing charge lifetime in DC polarized electron guns by offsetting the anode

Charge lifetime of strained superlattice GaAs photocathodes in DC guns is limited by ion back bombardment. It needs to be improved at least an order of magnitude to meet the requirements for future colliders such as Electron-Ion Collider (EIC). In this work, we propose and present simulation results for an offset anode scheme to increase charge lifetime in DC guns. This scheme eliminates the bombardment of high energy ions on the cathode and enables maximum usage of the available cathode area. Depending on the size of the available cathode area, this method can increase the charge lifetime by an order of magnitude compared to the current best alternative method. An anode assembly capable of in-vacuum movement is required for this method, which has been designed and fabricated at Brookhaven National Laboratory.

physics.acc-ph↗

arXiv2015

High-gradient High-charge CW Superconducting RF gun with CsK2Sb photocathode

High-gradient CW photo-injectors operating at high accelerating gradients promise to revolutionize many sciences and applications. They can establish the basis for super-bright monochromatic X-ray free-electron lasers, super-bright hadron beams, nuclear- waste transmutation or a new generation of microchip production. In this letter we report on our operation of a superconducting RF electron gun with a record-high accelerating gradient at the CsK2Sb photocathode (i.e. ~ 20 MV/m) generating a record-high bunch charge (i.e., 3 nC). We briefly describe the system and then detail our experimental results. This achievement opens new era in generating high-power electron beams with a very high brightness.

physics.acc-ph↗

arXiv2015

The Cornell-BNL FFAG-ERL Test Accelerator: White Paper

The Cornell-BNL FFAG-ERL Test Accelerator (C$\beta$) will comprise the first ever Energy Recovery Linac (ERL) based on a Fixed Field Alternating Gradient (FFAG) lattice. In particular, we plan to use a Non Scaling FFAG (NS-FFAG) lattice that is very compact and thus space- and cost- effective, enabling multiple passes of the electron beam in a single recirculation beam line, using the superconducting RF (SRF) linac multiple times. The FFAG-ERL moves the cost optimized linac and recirculation lattice to a dramatically better optimum. The prime accelerator science motivation for C$\beta$ is proving that the FFAG-ERL concept works. This is an important milestone for the Brookhaven National Laboratory (BNL) plans to build a major Nuclear Physics facility, eRHIC, based on producing 21 GeV electron beams to collide with the RHIC ion beams. A consequence of the C$\beta$ work would be the availability of significantly better, cost-effective, compact CW high-brightness electron beams for a plethora of scientific investigations and applications, such as X-ray sources, dark-matter and dark-energy searches, and industrial high-power Free-Electron Laser (FEL) applications. C$\beta$ brings together the resources and expertise of a large DOE National Laboratory, BNL, and a leading research university, Cornell. C$\beta$ will be built in an existing building at Cornell, for the most part using components that have been developed under previous R&D programs, including a fully commissioned world-leading photoemission electron injector, a large SRF accelerator module, and a high-power beam stop. The only elements that require design and construction from scratch is the FFAG magnet transport lattice. This white paper describes a project that promises to propel high-power, high-brightness electron beam science and applications to an exciting new level.

physics.acc-ph↗

arXiv2015

Design, prototyping and testing of a compact superconducting double quarter wave crab cavity

A novel design of superconducting Crab Cavity was proposed and designed at Brookhaven National Laboratory. The new cavity shape is a Double Quarter Wave or DQWCC. After fabrication and surface treatments, the niobium proof-of-principle cavity was cryogenically tested in a vertical cryostat. The cavity is extremely compact yet has a low frequency of 400 MHz, an essential property for service for the Large Hadron Collider luminosity upgrade. The electromagnetic properties of the cavity are also well matched for this demanding task. The demonstrated deflecting voltage of 4.6 MV is well above the requirement for a crab cavity in the future High Luminosity LHC of 3.34 MV. In this paper we present the design, prototyping and test results of the DQWCC.

physics.acc-ph↗

arXiv2011

High-energy high-luminosity electron-ion collider eRHIC

In this paper, we describe a future electron-ion collider (EIC), based on the existing Relativistic Heavy Ion Collider (RHIC) hadron facility, with two intersecting superconducting rings, each 3.8 km in circumference. A new ERL accelerator, which provide 5-30 GeV electron beam, will ensure 10^33 to 10^34 cm^-2 s^-1 level luminosity.

physics.acc-ph↗