A5053606094- Photocathodes and Microchannel Plates
- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Advanced Electron Microscopy Techniques and Applications
- Advanced X-ray Imaging Techniques
- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Radiation Therapy and Dosimetry
- Plasmonic and Surface Plasmon Research
- X-ray Spectroscopy and Fluorescence Analysis
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Advancements in Photolithography Techniques
- Advanced Fiber Laser Technologies
- Machine Learning in Materials Science
- Photonic and Optical Devices
- Pulsed Power Technology Applications
- Crystallography and Radiation Phenomena
- Dark Matter and Cosmic Phenomena
- Atomic and Subatomic Physics Research
- Advanced Fluorescence Microscopy Techniques
- Advanced Semiconductor Detectors and Materials
- Laser Design and Applications
- Laser Material Processing Techniques
Cornell University
2015-2025
University of Chicago
2022
University of Salerno
2022
Brookhaven National Laboratory
2022
University of California, Los Angeles
2016-2019
Arizona State University
2018
Lehigh University
2008
Ultralow emittance (≤20 nm, normalized) electron beams with 105 electrons per bunch are obtained by tightly focusing an ultrafast (∼100 fs) laser pulse on the cathode of a 1.6 cell radio frequency photoinjector. Taking advantage small initial longitudinal emittance, downstream velocity bunching cavity is used to compress beam <10 fs rms length. The measurement performed using thick high-voltage deflecting which shown be well suited measure ultrashort durations beams, provided that reaches...
High-power, high-brightness electron beams are of interest for many applications, especially as drivers free lasers and energy recovery linac light sources. For these particular photoemission injectors used in most cases, the initial beam brightness from injector sets a limit on quality generated at end accelerator. At Cornell University, we have built such high-power using DC gun followed by superconducting accelerating module. Recent results will be presented demonstrating record setting...
We present a detailed study of the six-dimensional phase space electron beam produced by Cornell Energy Recovery Linac Photoinjector, high-brightness, high repetition rate (1.3 GHz) DC photoemission source designed to drive hard x-ray energy recovery linac (ERL). A complete simulation model injector has been constructed, verified measurement, and optimized. Both horizontal vertical 2D transverse spaces, as well time-resolved (sliced) space, were simulated directly measured at end for 19 77...
THz radiation promises breakthrough advances in compact advanced accelerators due to the high frequency and GV/m fields achievable, orders of magnitude larger than conventional radiofrequency (RF) based accelerators. Compared laser-driven schemes, large phase acceptances THz-driven are advantageous for operation with sizable charge. Despite burgeoning research, sources, particularly laser-based ones, cannot yet compete efficiency RF amplifiers average current Nevertheless, THz-based space...
Abstract Advances in ultrafast laser technology and nanofabrication have enabled a new class of particle accelerator based upon miniaturized laser-driven photonic structures. However, developing useful on this approach requires control the dynamics at field intensities approaching damage limit. We measure acceleration fused silica dielectric driven by fields up to 9 GV m −1 observe record 1.8 accelerating mode. At these is beyond its linear response self-phase modulation changes phase...
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...
The properties of photoemission electron sources determine the ultimate performance a wide class accelerators and photon detectors. To date, all high-efficiency visible-light photocathode materials are either polycrystalline or exhibit intrinsic surface disorder, both which limit emitted beam brightness. In this Letter, we demonstrate synthesis epitaxial thin films Cs_{3}Sb on 3C-SiC (001) using molecular-beam epitaxy. Films as 4 nm have quantum efficiencies exceeding 2% at 532 nm. We also...
Using an 800 nm, 45 fs pulse-front-tilted laser we demonstrate a record 315 keV energy gain in dual grating dielectric accelerator (DLA) and average accelerating gradients of 560 MV/m over 0.5 mm. These results open new regime DLA characterized by significant evolution the beam distribution longitudinal phase space, corresponding to >1/4 synchrotron oscillation. By tilting wavefront control resonant velocity observe net gain, indicating that tapered optical could be used achieve very high gain.
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{...
Achieving a low mean transverse energy or temperature of electrons emitted from the photocathode-based electron sources is critical to development next-generation and compact x-ray free lasers ultrafast diffraction, spectroscopy, microscopy experiments. In this Letter, we demonstrate record 5 meV cryo-cooled (100) surface copper using near-threshold photoemission. Further, also show that spread obtained such less than 11.5 meV, making it smallest source known date: more an order magnitude...
Driven by life-science applications, a mega-electron-volt Scanning Transmission Electron Microscope (MeV-STEM) has been proposed here to image thick frozen biological samples as conventional (TEM) may not be suitable thicker than 300–500 nm and various volume electron microscopy (EM) techniques either suffering from low resolution, or speed. The high penetration of inelastic scattering signals MeV electrons could make the MeV-STEM an appropriate microscope for 10 μm more with nanoscale...
Metal photocathodes are an important source of high-brightness electron beams, ubiquitous in the operation both large-scale accelerators and table-top microscopes. When surface a metal is nanoengineered with patterns on order optical wavelength, it can lead to excitation confinement surface-plasmon-polariton waves that drive nonlinear photoemission. In this work, we aim evaluate gold plasmonic nanogrooves as concept for producing bright beams via We do by first comparing their properties...
Thermal emittance measurements of a CsK2Sb photocathode at several laser wavelengths are presented. The is obtained with solenoid scan technique using high voltage dc photoemission gun. thermal 0.56+/-0.03 mm-mrad/mm(rms) 532 nm wavelength. results compared simple model and found to be in good agreement.
We present the results of an experiment where a short focal length (~ 1.3 cm) permanent magnet electron lens is used to image micron-size features metal sample in single shot, using ultra- high brightness ps-long 4 MeV beam from radiofrequency photoinjector. Magnifcation ratios excess 30x were obtained triplet compact, small gap (3.5 mm), Halbach-style quadrupoles with nearly 600 T/m field gradients. These pave way to- wards shot time-resolved microscopy and open new opportunities applications beams.
We measure the tradeoff between quantum efficiency and intrinsic emittance from a NaKSb photocathode at three increasing wavelengths (635, 650, 690 nm) or below energy of bandgap plus electron affinity, hν≤Eg+Ea. These measurements were performed using high voltage dc gun for varied surface fields 1.4−4.4 MV/m. Measurements are two different methods found to agree. At longest wavelength available, nm, was 0.26 μm/mm-rms with ∼10−4. The suitability emitting threshold various low applications...
We report the design and performance of a time-resolved electron diffraction apparatus capable producing intense bunches with simultaneously single digit micrometer probe size, long coherence length, 200 fs rms time resolution. measure 5d (peak) beam brightness at sample location in micro-diffraction mode to be 7×1013 A/m2 rad2 . To generate high bunches, system employs efficiency, low emittance semiconductor photocathodes driven wavelength near photoemission threshold repetition rate up 250...
Alkali antimonides are well established as high efficiency, low intrinsic emittance photocathodes for accelerators and photon detectors. However, conventionally grown alkali antimonide films polycrystalline with surface disorder roughness that can limit achievable beam brightness. Ordering the crystalline structure of has potential to deliver higher brightness electron beams by reducing enabling engineering material properties at level atomic layers. In this report, we demonstrate growth...
The development of high-brightness electron sources is critical to state-of-the-art accelerator applications like X-ray free laser (XFEL) and ultra-fast microscopy. Cesium telluride chosen as the source material for multiple cutting-edge XFEL facilities worldwide. This manuscript presents first demonstration growth highly crystalized epitaxial cesium thin films on 4H-SiC graphene/4H-SiC substrates with ultrasmooth film surfaces. ordering was characterized by in situ reflection high energy...
The Cornell University energy recovery linac (ERL) photoinjector has recently demonstrated operation at 20 mA for approximately 8 hours, utilizing a multialkali photocathode deposited on Si substrate. We describe the recipe deposition, and will detail parameters of run. Post-run analysis indicates presence significant damage to substrate, perhaps due ion back-bombardment from residual beam line gas. While exact cause substrate remains unknown, we multiple surface characterization techniques...
We determine the limit of lowest achievable photoemitted electron temperature, and therefore maximum brightness, from unstructured photoemitting materials producing dense relativistic or nonrelativistic photoelectron beams. The is given by heating that occurs just after emission into vacuum, due to poorly screened Coulomb interactions equivalent disorder induced seen in ultracold neutral plasmas. first show traditional analytic methods collisions fail for calculation this strongly coupled...
Abstract C 3 is an opportunity to realize e + - collider for the study of Higgs boson at √ s = 250 GeV, with a well defined upgrade path 550 GeV while staying on same short facility footprint [2,3]. based fundamentally new approach normal conducting linear accelerators that achieves both high gradient and efficiency relatively low cost. Given advanced state designs, key system requires technical maturation main linac. This paper presents staged towards demonstrate technology Direct (source...