A5064186039- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Microwave Engineering and Waveguides
- Radio Frequency Integrated Circuit Design
- Superconducting Materials and Applications
- Pulsed Power Technology Applications
- Photonic and Optical Devices
- Superconducting and THz Device Technology
- Particle Detector Development and Performance
- Electromagnetic Simulation and Numerical Methods
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Advanced Radiotherapy Techniques
- Laser-Plasma Interactions and Diagnostics
- Magnetic confinement fusion research
- Advanced X-ray Imaging Techniques
- Nuclear Physics and Applications
- Photocathodes and Microchannel Plates
- Physics of Superconductivity and Magnetism
- Plasma Diagnostics and Applications
- Electromagnetic Compatibility and Measurements
- Superconductivity in MgB2 and Alloys
- Antenna Design and Analysis
- Microwave and Dielectric Measurement Techniques
SLAC National Accelerator Laboratory
2015-2024
Menlo School
2006-2023
Stanford University
2012-2023
Georgia Institute of Technology
2023
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati
2010-2019
Istituto Nazionale di Fisica Nucleare
2019
UCLA Health
2018
Linac Coherent Light Source
2002-2016
Stanford Synchrotron Radiation Lightsource
1999-2016
Brookhaven National Laboratory
2012
We describe recent advances in the study of particle acceleration using dielectric near-field structures driven by infrared lasers, which we refer to as Dielectric Laser Accelerators. Implications for high energy physics and other applications are discussed.
A design for a compact x-ray light source (CXLS) with flux and brilliance orders of magnitude beyond existing laboratory scale sources is presented. The based on inverse Compton scattering high brightness electron bunch picosecond laser pulse. accelerator novel high-efficiency standing-wave linac rf photoinjector powered by single ultrastable transmitter at X-band frequency. efficiency permits operation repetition rates up to 1 kHz, which further boosted 100 kHz operating trains bunches pC...
A bstract We propose an approach to search for axion dark matter with a specially designed superconducting radio frequency cavity, targeting axions masses m ≲ 10 − 6 eV. Our exploits axion-induced transitions between nearly degenerate resonant modes of ∼ GHz. scan over mass is achieved by varying the splitting two modes. Compared traditional approaches, this allows parametrically enhanced signal power lighter than The projected sensitivity covers unexplored parameter space QCD 8 eV and...
The general concept of radiation therapy used in conventional cancer treatment is to increase the therapeutic index by creating a physical dose differential between tumors and normal tissues through precision targeting, image guidance, beams that deliver with high conformality, e.g., protons ions. However, cure are still limited tissue toxicity, corresponding side effects. A fundamentally different paradigm for increasing has emerged recently, supported preclinical research, based on FLASH...
Abstract Construction of an e + - Higgs factory has been identified as a major goal for particle physics. Such collider will offer precise measurements the bosons couplings to other particles. A extendable in energy can also establish self-coupling, measure coupling top quark, and expand reach probe new phenomena. We propose strategy energy-extendable based on linear accelerator technology. This offers compact cost-effective design that could be realized project US. The core technologies...
We present the experimental results of a systematic study rf breakdown phenomenon in high vacuum accelerator structures. In this study, surface processing, geometry, and materials structures have been varied, one parameter at time. The rate or alternatively, probability breakdown/pulse/meter has recorded for different operating parameters. These statistical data reveal strong dependence on magnetic field, alternatively pulsed heating. This is contrast to classical view electric field...
Cyclic thermal stresses produced by rf pulsed heating can be the limiting factor on attainable reliable gradients for room temperature linear accelerators. This is especially true structures that have complicated features wakefield damping. These limits could pushed higher using special types of copper, copper alloys, or other conducting metals in constructing partial complete accelerator structures. Here we present an experimental study aimed at determining potential these materials...
Static magnetic undulators used by x-ray light sources are fundamentally too limited to achieve shorter undulator periods and dynamic control. To overcome these limitations, we report experimental demonstration of a novel short-period microwave undulator, essentially Thomson scattering device, that has yielded tunable spontaneous emission seeded coherent radiation. Its equivalent period (λu) is 13.9 mm while it achieved an field 0.65 T. For future-generation sources, this device promises...
Vacuum radio-frequency (rf) breakdown is one of the major factors that limit operating accelerating gradients in rf particle accelerators. The occurrence breakdowns was shown to be probabilistic, and can characterized by a rate. Experiments with hard copper cavities showed harder materials reach larger for same We study effect cavity material on short $X$-band standing wave structures. Here we report results from tests structure at cryogenic temperatures. At greater than $150\text{ }\text{...
We are exploring the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. present experimental results tests performed in metallic mm-wave accelerating structures. These experiments were carried out facility for advanced accelerator (FACET) SLAC National Accelerator Laboratory. The fields excited by FACET ultrarelativistic electron beam. compared performances metal structures made with copper stainless steel. frequency fundamental mode, propagating speed light,...
We report the experimental demonstration of a mm-wave electron accelerating structure powered by high-power rf source. demonstrate reliable coupling an unprecedented power—up to 575 kW into accelerator using quasi-optical setup. This standing wave consists single-cell copper cavity and Gaussian TM01 mode converter. The is 110 GHz, 10-ns long pulses. These pulses are chopped from 3 ms gyrotron oscillator laser-driven silicon switch. show high gradient up 230 MV/m that corresponds peak surface...
In the field of beam physics, two frontier topics have taken center stage due to their potential enable new approaches discovery in a wide swath science. These areas are: advanced, high gradient acceleration techniques, and x-ray free electron lasers (XFELs). Further, there is intense interest marriage these fields, with goal producing very compact XFEL. this context, recent advances radio-frequency cryogenic copper structure research opened door use surface electric fields between 250 500...
Recent studies of the performance radio-frequency (rf) copper cavities operated at cryogenic temperatures have shown a dramatic increase in maximum achievable surface electric field. We propose to exploit this development enable new generation photoinjectors that may attain, through enhancement launch field photocathode, significant five-dimensional electron beam brightness. present detailed dynamics associated with such system, by examining an S-band photoinjector $250\text{ }\text{...
Purpose: To measure radiation dose in a water‐equivalent medium from very high‐energy electron (VHEE) beams and make comparisons to Monte Carlo (MC) simulation results. Methods: Dose polystyrene phantom delivered by an experimental VHEE beam line was measured with Gafchromic films for three 50 MeV two 70 Gaussian of 4.0–6.9 mm FWHM compared corresponding MC‐simulated distributions. MC the calculated EGSnrc/BEAMnrc DOSXYZnrc codes based on setup. Additionally, effect 2% energy measurement...
We present a proposal for cold copper distributed coupling accelerator that can provide rapid route to precision Higgs physics with compact 8 km footprint. This is based on recent advances increase the efficiency and operating gradient of normal conducting accelerator. technology also provides an $e^{+}e^{-}$ collider path at multi-TeV energies. In this article, we describe our vision near-term R&D program needed pursue it.
A compact low-level RF (LLRF) control system based on system-on-chip (RFSoC) technology has been designed for the Advanced Concept Compact Electron Linear-accelerator (ACCEL) program, which challenging requirements in both performance and size, weight power consumption (SWaP). The LLRF solution employs direct sampling technique of RFSoC, samples signals directly without any analogue up down conversion. Compared with conventional heterodyne architecture used linear accelerator (LINAC),...
We present an experimental study of a high gradient metallic accelerating structure at sub-THz frequencies, where we investigated the physics rf breakdowns. Wakefields in were excited by ultrarelativistic electron beam. first quantitative measurements gradients and metal vacuum breakdowns cavities. When beam travels off axis, deflecting field is induced addition to longitudinal field. measured forces observing displacement changes shape bunch. This behavior can be exploited for...
We present a topology for linear accelerators (linacs) that permits larger degrees of freedom the optimization individual cavity shapes. The power is distributed to cavities through waveguide with periodic apertures guarantees correct phases and amplitudes along structure. This optimizes consumption efficiency allows manipulation surface fields high gradient operation. It also provides possibility low-temperature manufacturing techniques use novel materials. greatly enhanced performance both...
The production of high spectral brilliance radiation from electron beam sources depends critically on the qualities. One must obtain very brightness, implying simultaneous peak current and low emittance. These attributes are enabled through use field acceleration in a radio-frequency (rf) photoinjector source. Despite fields currently utilized, there is limit achievable brightness operation, range tens Ampere. This limitation can be overcome by hybrid standing wave/traveling wave structure;...
The application of radio frequency (RF) vacuum electronics for the betterment human condition began soon after invention first tubes in 1920s and has not stopped since. Today, microwave devices are powering important applications health treatment, material biological science, wireless communication-terrestrial space, Earth environment remote sensing, promise safe, reliable, inexhaustible energy. This article highlights some exciting frontiers electronics.
We present a multimode $X$-band rf pulse compression system suitable for TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single unit required to produce 400 ns pulses with 475 MW of peak power. Each should power approximately 5 m accelerator structures. design consists two 75 klystrons and dual-moded resonant-delay-line that produces flat output pulse. components are all overmoded, most designed...