A5029212832- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Terahertz technology and applications
- Magnetic confinement fusion research
- Microwave Engineering and Waveguides
- Superconducting and THz Device Technology
- Plasma Diagnostics and Applications
- Acoustic Wave Resonator Technologies
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Advanced NMR Techniques and Applications
- Physics of Superconductivity and Magnetism
- Particle Accelerators and Free-Electron Lasers
- Radio Frequency Integrated Circuit Design
- Photonic and Optical Devices
- Pulsed Power Technology Applications
- Spectroscopy and Quantum Chemical Studies
- Metal and Thin Film Mechanics
- Astrophysics and Cosmic Phenomena
- Electron Spin Resonance Studies
University of California, Davis
2014-2024
Kansas State University
2017
Lancaster University
2016
University of Electronic Science and Technology of China
2016
This paper describes the design and construction of MicroBooNE liquid argon time projection chamber associated systems. is first phase Short Baseline Neutrino program, located at Fermilab, will utilize capabilities detectors to examine a rich assortment physics topics. In this document details specifications, assembly procedures, acceptance tests are reported.
We report on hot test measurements of a wide-bandwidth, 220-GHz sheet beam traveling wave tube amplifier developed under the Defense advanced research projects agency (DARPA) HiFIVE program. Nano-computer numerical control (CNC) milling techniques were employed for precision fabrication double vane, half-period staggered interaction structures achieving submicrometer tolerances and nanoscale surface roughness. A multilayer diffusion bonding technique was implemented to complete structure...
Nano-computer numerical control (CNC) machining technology is employed for the fabrication of sub-THz (100-1000 GHz) vacuum electron devices. Submicron feature tolerances and placement accuracy have been achieved surface roughness a few tens nanometers has demonstrated providing high-quality radio frequency (RF) transmission reflection parameters on tested circuit structures. Details manufacturing approach are reported following devices: W-band sheet beam (SB) klystron, two designs 220-GHz...
Understanding of the anomalous transport 1 attributed to short-scale length microturbulence through 2 collective scattering diagnostics is key development 3 nuclear fusion energy.Signals in subterahertz (THz) range 4 (0.1-0.8 THz) with adequate power are required map wider 5 wavenumber regions.The progress a joint international effort 6 devoted design and realization novel backward-wave 7 oscillators at 0.346 THz above output W 8 reported herein.The sources possess desirable 9...
Vacuum electron devices are the most promising solution for generation of watt-level power at millimeter wave and terahertz frequencies. However, three-dimensional nature metal structures required to provide an effective interaction between beam THz signal poses significant fabrication challenges. At increasing frequency, losses present a serious detrimental effect on performance. In particular, skin depth, order one hundred nanometers or less, constrains maximum acceptable surface roughness...
A carefully designed waveguide-based millimeter-wave notch filter, operating at 140 GHz, safeguards plasma diagnostic instruments from gyrotron leakage. Utilizing cylindrical cavity resonators with aperture coupling, the filter efficiently resonates GHz wave-power into TE11p mode, optimizing various geometrical parameters for practical fabrication and high-yield production. Thorough thermal analysis ensures its ability to handle power. The achieves outstanding performance over 90 dB...
Nuclear fusion energy is perhaps one of the most demanding challenges that scientific community facing. Unfortunately, plasma affected by microturbulence, which still not fully understood, but can degrade confinement. The 0.346-THz backward-wave oscillator (BWO) enabling device for a high-k collective scattering diagnostic will provide unprecedented insight on turbulence thereby contributing to realization operational reactors. This paper describes final fabrication phase BWO jointly...
The complete design process of a high-frequency circuit for 263 GHz staggered double grating, sheet beam traveling wave tube is presented in this article. This device, use pulsed electron paramagnetic resonance spectrometer instrument, requires >30 dB gain and 20 bandwidth centered at GHz. In addition to the standard Pierce analysis point by particle cell (PIC) simulation, novel fast pulse response technique was utilized determine accurate synchronization voltage test ``hot" feature circuit....
The understanding of plasma turbulence in nuclear fusion is related to the availability powerful THz sources and possibility map wider regions. A novel approach realize compact be implemented diagnostic at NSTX experiment (Princeton Plasma Physics Laboratory, USA) reported.
Abstract The notch filter plays a crucial role as protective component in microwave diagnostics, primarily by addressing issues related to catastrophic interference. Designed for millimeter-wave diagnostics on the stellarator Wendelstein 7-X (W7-X), WR-6 waveguide-based has been successfully developed effectively isolate leakage from auxiliary heating gyrotrons operating at 140 GHz. incorporates cylindrical cavities resonating GHz TE 11p mode, with coupling structures that are designed and...
Research conducted in parallel with the construction of various vacuum electronic devices, including a 220 GHz Sheet Beam Traveling Wave Tube (SBTWT), 263 SBTWT, and two 346 Backward Oscillators (BWOs), has demonstrated that data garnered from manufacturing process helps improve performance, reduce time to build, lower cost subsequent devices. The collected metrology, microscopy, control are also critical improving future device builds provide powerful insight into nature fabricating high...
Two backward wave oscillator (BWO) designs are proposed for a 346 GHz source fusion plasma diagnostics applicable the MAST and NSTX-U devices. Both feature double grating machined from bulk copper, using nano-machining technology.
Applications such as fusion diagnostics, imaging and security systems require high frequency sources. As part of a joint international effort regarding novel THz BWOs, double staggered grating sheet beam BWO at 346 GHz is underdevelopment being fabricated. Design work has been done on various components, with nano machining cold testing the slow wave structure completed.
The progress in microfabrication techniques and three dimensional electromagnetic simulations have enabled the fabrication of vacuum electron devices up to 1 THz. In particular, backward wave oscillator is a compact powerful THz source, based on transfer energy from an beam (EM) propagating slow structure. paper reports design challenges realize near-THz Backward Wave Oscillator for plasma diagnostics nuclear fusion. optics confinement as well structure are described. Manufacturing device...
A new approach to realize THz BWOs relaxing the assembly challenge is presented. An international consortium including UC Davis, Beijing Vacuum Electronics Research Institute (BVERI), and Lancaster University involved in design fabrication of 0.346 replace bulky FIR laser at plasma diagnostic NSTX-U fusion device. The use a highly energetic beam permit wide channel, double corrugated waveguide achieve about 4 W output power THz.
A collaboration between UC Davis, Lancaster University, Beijing Vacuum Electronics Research Institute (BVERI), and the University of Electronic Science Technology China (UESTC) is developing a 346 GHz backward wave oscillator (BWO) for use as source in plasma fusion diagnostics, medical, biological, security imaging systems. Development new electron gun optics that achieve almost 100% beam transmission based on particle-in-cell simulations presented along with comparisons cold hot...
346GHz backward wave oscillations (BWOs) have been considered as a key device for fusion plasma diagnostics, whose development is joint project under collaboration among Beijing Vacuum Electronics Research Institute (BVERI), University of California Davis (UC Davis) and Lancaster University. In this paper, we report on some progress being made in the BWO.
The development of collective scattering diagnostics is essential for understanding the anomalous transport attributed to short scale length microturbulence which poses a threat nuclear fusion reactors. Signals in sub-THz range (0.1 – 0.8 THz) with adequate power are required probe plasma. A joint international effort therefore devoted design and realization novel backward wave oscillators at 0.346 THz above output 1 Watt replace bulky, high maintenance optically pumped FIR lasers so far...
Vacuum electron devices are the most promising solution to generate power at Watt level millimeter waves and terahertz frequencies. The three dimensional nature of metal structures required provide an effective interaction between beam THz signal poses relevant fabrication challenges. At increase frequency, losses a detrimental effect on performance. In particular, skin depth, in order one hundred nanometers or less, constrains maximum surface roughness surfaces below those values....
Nuclear fusion is probably the most demanding challenge scientific community facing. The plasma a delicate material that has to be properly shaped achieve high efficiency process. Unfortunately, affected by micro-turbulences still not fully understood, detrimental for reactor functioning. diagnostic of fundamental technique needs advanced approaches full mapping behavior. 0.346 THz backward wave oscillator enabling devices high-k will provide unprecedented insight on turbulences leading...
The double corrugated waveguide has been demonstrated to be a suitable solution for the design and fabrication of 0.346 GHz backward wave oscillator. One main challenges is coupling with flanges. Two different couplers are investigated compared. S-Parameters two configurations have simulated it that both perform well, producing better than -20dB S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> parameter over bandwidth about 10 GHz.
A unique spectrometer is under construction to enable pulsed electron paramagnetic resonance at 263 GHz. The instrument will enhance resolution of the g-tensor components narrow organic radical signals providing a major advantage when probing protonation and hydrogen bonding effects on radicals' electronic structures. This capability enabled by moderate power (50 W), 5.5% duty 20 GHz bandwidth travelling wave tube amplifier consisting high current density sheet beam gun, periodic cusped...
The fabrication of slow wave structures for THz vacuum electronic devices presents substantial technology challenges and requires tight tolerances as the frequency increases. 0.346 backward oscillator plasma diagnostics is in final phase. It based on Double Corrugated Waveguide, fabricated by high accuracy CNC milling. In this paper, variation height due to bonding process, with respect nominal value effect electron beam misalignment along propagation direction will be discussed, predicting...
An international consortium including the University of California, Davis (UC Davis), Beijing Vacuum Electronics Research Institute (BVERI), and Lancaster is involved in design fabrication 0.346 THz BWOs to replace bulky FIR laser at plasma diagnostic NSTX-U fusion device. The use a highly energetic beam wide channel double corrugated waveguide has been found improve performance Watt level facilitate alignment assembly.