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Dudas, A.

Publications and source records attributed to Dudas, A..

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Magnetron R&Ds for High Efficiency CW RF Sources of Particle Accelerators

A proof of principle experiment carried out at JLab's magnetron R&D test stand has demonstrated a -25dB injection signal to phase lock a 2.45GHz 1.2kW CW magnetron within 2.1 Hz of root mean square deviation (RMSD) value with the optimization of magnetic field trimming of ±25% in order to overcome the frequency pushing of more than 4MHz in the RF power output range of 45-100%. In addition, a test stand for a newly built 1497 MHz, 13kW, CW magnetron prototype is ready for the high power injection test with outcome aimed for the CEBAF klystron replacement. Based on these R&D results, a 915MHz, 2?75kW CW commercial heating type magnetron system is being developed as high efficiency (>80%) RF source to drive an electron linac for industrial applications.

Wang, H.↗
DOE OSTI2018

INJECTION LOCKED 1497 MHZ MAGNETRON

A novel injection-locked 1497 MHz 13 kW AM magnetron design is presented. An anode designed to minimize eddy currents due to the modulated magnetic field is presented. Thermal calculations of two design options are also presented. An extra degree of freedom in the anode construction is made possible by the fact that the magnetron is injection locked; as a result some additional design details that can be utilized in the cooling network for the magnetron anode are presented.

Wang, Haipeng↗
DOE OSTI2018

Magnetron R&D toward the Amplitude Modulation Control for SRF Accelerator

The scheme of using a high efficiency magnetron to drive a superconducting radio frequency (SRF) accelerator cavity needs not only the injection phase locking but also the amplitude modulation to compensate the cavity's microphomics caused cavity voltage change and the beam loading variation. To be able to do a fast and efficient modulation, the magnetron's magnetic field has to be trimmed by an external coil to compensate the frequency pushing effect due to the anode current change [1]. A low eddy current magnetron body has been designed and built [2]. This paper will present the analytical prediction, simulation and experimental results on the 2.45 GHz magnetron test stand with the modulation frequency up to 1 kHz. In addition, the progresses on the injection lock to a copper cavity, new 1497 MHz magnetron prototype, 13 kW high power magnetron test stand development and newly built low level RF (LLRF) controller for the amplitude modulation will be reported.

Rimmer, Robert A.↗
DOE OSTI2017

R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Simulation and Experimental Studies of a 2.45GHz Magnetron Source for an SRF Cavity with Field Amplitude and Phase Controls

Phase lock to an SRF cavity by using injection signal through output waveguide of a magnetron has been demonstrated [1, 3]. Amplitude control using magnetic field trimming and anode voltage modulation has been studied using MATLAB/Simulink simulations [2]. Based on these, we are planning to use an FPGA based digital LLRF system, which allows applying various types of control algorithms in order to achieve the required accelerating field stability. Since the 1497 MHz magnetron is still in the design stage, the proof of principle measurements of a commercial 2450 MHz magnetron are carried out to characterize the anode I-V curve, output power (the tube electronic efficiency), frequency dependence on the anode current (frequency pushing) and the Rieke diagram (frequency pulling by the reactive load). Based on early Simulink simulation, experimental data and extension of the Adler equation governing injection phase stability by Chen’s model, the specification of the new LLRF control chassis for both 2450 and 1497MHz systems are presented in this paper.

Wang, Haipeng↗
DOE OSTI2014

HIGH POWER CO-AXIAL COUPLERS FOR SRF CAVITIES

High Power RF couplers are required in a wide range of accelerator projects using superconducting RF cavities. There are a number of coupler designs for different SRF cavities, with various coupler window shapes. A majority of the SRF cavities adopt dual window design, partly due to the concern of reliability. We have proposed a novel robust coax dual window SRF coupler design using two pre-stressed disc windows. The matching at certain frequency is achieved by choosing the window spacing so that the RF reflected from both windows will cancel each other, without the need of additional matching elements. We have fabricated such a dual window assembly with the dimensions of the EIA 3-1/8 50 ? coax line. Larger sizes can be used if higher power handling capacity is desired. The assembly were originally designed to match at 400 MHz. Low power tests showed good agreement with the design. Without active cooling, the assembly was tested with traveling wave and standing wave up to 12 kW CW at 1.5 GHz with matching irises. In this paper, we will present our latest progress in the fabrication and testing of the windows.

Guo, J.↗
DOE OSTI2013

An Efficient RF Source for Jlab

We propose the development of a highly reliable high efficiency RF source for JLAB with a lower lifetime cost operating at 80% efficiency with system operating costs of about 0.7M$/year for the 6 GeV machine. The design of the RF source will be based upon two injection locked magnetrons in a novel combining architecture for amplitude modulation and a cross field amplifier (CFA) as an output tube for the 12 GeV upgrade. A cost analysis including efficiency and reliability will be performed to determine the optimum system architecture. Several different system architectures will be designed and evaluated for a dual injection locked magnetron source using novel combining techniques and possibly a CFA as the output tube. A paper design for the 1497 MHz magnetron system will be completed. The optimum system architecture with all relevant specifications will be completed so that a prototype can be built.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

High Power Co-Axial Coupler

A very high power Coax RF Coupler (MW-Level) is very desirable for a number of accelerator and commercial applications. For example, the development of such a coupler operating at 1.5 GHz may permit the construction of a higher-luminosity version of the Electron-Ion Collider (EIC) being planned at JLab. Muons, Inc. is currently funded by a DOE STTR grant to develop a 1.5-GHz high-power doublewindowcoax coupler with JLab (about 150 kW). Excellent progress has been made on this R&D project, so we propose an extension of this development to build a very high power coax coupler (MW level peak power and a max duty factor of about 4%). The dimensions of the current coax coupler will be scaled up to provide higher power capability.

43 PARTICLE ACCELERATORS↗