About

Carl Schroeder is an Adjunct Professor in the Department of Nuclear Engineering at the University of California, Berkeley, and a Senior Scientist in the Accelerator Technology & Applied Physics Division at Lawrence Berkeley National Laboratory. He also serves as the Deputy Director of the BELLA (Berkeley Lab Laser Accelerator) Center at Lawrence Berkeley National Laboratory. Dr. Schroeder received undergraduate degrees in Mathematics and Physics with High Honors from the University of Maryland, College Park, in 1994, and completed his doctorate in Physics at the University of California, Berkeley, in 1999, supported by a DOE Fusion Science Fellowship. His postdoctoral research focused on the development of x-ray free-electron lasers at the SLAC National Accelerator Laboratory. His research interests include intense laser-plasma and beam-plasma interactions, plasma-based accelerators, advanced acceleration concepts, novel radiation sources, free-electron lasers, and related topics. Dr. Schroeder has made significant theoretical contributions to the physics of intense laser-plasma interactions, with applications to plasma-based accelerators and light sources. He is recognized as a fellow of the American Physical Society and has received awards such as the John Dawson Award for Excellence in Plasma Physics Research and the Lawrence Berkeley National Laboratory Outstanding Performance Award.

Research topics

• Computer Science
• Physics
• Nuclear physics
• Political Science
• Sociology
• Optics
• Engineering
• Nuclear medicine
• Medicine
• Medical physics
• Aerospace engineering
• Mechanical engineering
• Business
• Database
• Systems engineering
• Particle physics
• Nuclear engineering

Selected publications

• Investigation of correlations between spectral phase fluctuations of the laser pulse and the performance of an LPA

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2025-02-04 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Multi-messenger dynamic imaging of laser-driven shocks in water using a plasma wakefield accelerator

  Research Square · 2025-02-03 · 2 citations

  preprintOpen access
  PublisherOA PDFDOI

• Bayesian Optimization of Laser-Wakefield Acceleration via Spectral Pulse Shaping

  ArXiv.org · 2025-12-09

  preprintOpen accessSenior author

  In this paper, we investigate the effect of spectral pulse shaping of the laser driver on the performance of channel-guided, laser-plasma accelerators. The study was carried out with the assistance of Bayesian optimization using particle-in-cell simulations. We used a realistic plasma profile based on a novel optical-field-ionized channel technique with ionization injection and low on-axis plasma densities to maximize the energy gain of the electron bunch trailing the laser. Spectral shaping allows us to modify the temporal profile of the laser driver while keeping the laser energy constant, affecting the acceleration and injection processes. Given the complexity and breadth of the parameter space in question, we used numerical optimization to identify high performers. In particular, we found laser profiles with additional spectral content that, when used with optimal plasma channel parameters, result in charge content an order of magnitude higher than the baseline Gaussian case while also increasing the mean energy of the electron bunch.

  PublisherOA PDFDOI

• Enhanced Isomer Population via Direct Irradiation of Solid-Density Targets Using a Compact Laser-Plasma Accelerator

  Physical Review Letters · 2025-02-07 · 4 citations

  articleOpen access

  Excitation of long-lived states in bromine nuclei using a tabletop laser-plasma accelerator providing pulsed (<100 fs) electron beams provided a sensitive probe of γ strength and level densities in the nuclear quasicontinuum and may indicate angular momentum coupling through electron-nuclear interactions. Solid-density active LaBr_{3} targets absorb real and virtual photons up to 35±2.5 MeV and deexcite through γ cascade into different states. A factor of 4.354±0.932 enhancement of the ^{80}Br^{m}/^{80}Br^{g} isomeric ratio was observed following electron irradiation, as compared to bremsstrahlung. Additional angular momentum transfer could possibly occur through nuclear-plasma or electron-nuclear interactions enabled by the ultrashort electron beam. Further investigation of these mechanisms could have far-reaching impact including decreased storage of long-term nuclear waste and an improved understanding of heavy element formation in astrophysical settings.

  PublisherOA PDFDOI

• Demonstration of a reliable, high-gain laser plasma accelerator-driven free electron laser

  2025-06-06

  article
  PublisherDOI

• Longitudinal tapering in gas jets for increased efficiency of 10-GeV class laser plasma accelerators

  Review of Scientific Instruments · 2025-04-01 · 1 citations

  articleOpen access

  Modern laser plasma accelerators often require plasma waveguides tens of centimeters long to propagate a high-intensity drive laser pulse. Tapering the longitudinal gas density profile in 10 cm scale gas jets could allow for single stage laser plasma acceleration well beyond 10 GeV with current petawatt-class laser systems. Via simulation and interferometry measurements, we show density control by longitudinally adjusting the throat width and jet angle. Density profiles appropriate for tapering were calculated analytically and via particle-in-cell simulations and were matched experimentally. These simulations show that tapering can increase electron beam energy using 19 J laser energy from ∼9 GeV to >12 GeV in a 30 cm plasma and the accelerated charge by an order of magnitude.

  PublisherOA PDFDOI

• Measurement of directional muon beams generated at the Berkeley Lab Laser Accelerator

  Physical Review Accelerators and Beams · 2025-10-08 · 4 citations

  articleOpen access

  We present the detection of directional muon beams produced using a PW laser facility at the Lawrence Berkeley National Laboratory. The muon source is a multi-GeV electron beam generated in a <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>30</a:mn><a:mrow><a:mtext> </a:mtext><a:mtext> </a:mtext><a:mi>cm</a:mi></a:mrow></a:math> laser-plasma accelerator interacting with a high-<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mi>Z</c:mi></c:math> converter target. The GeV photons resulting from the interaction are converted into a high-flux, directional muon beam via pair production. By employing scintillators to capture delayed events, we were able to identify the produced muons and characterize the source. Using theoretical knowledge of the muon production process combined with simulations that are in excellent agreement with the experiments, we demonstrate that laser-plasma accelerators have the capability of generating electron beams with characteristics suitable to produce GeV-scale muons that offer unique advantages with respect to the cosmic background. Laser-plasma-accelerator-based muon sources can therefore enhance muon imaging applications thanks to their compactness, directionality, and high yields, which reduce the exposure time by orders of magnitude compared to cosmic ray muons. Using the eant4-based simulation code we developed to gain insight into the experimental results, we can design future experiments and applications based on LPA-generated muons.

  PublisherDOI

• Hydrodynamic modeling of plasma channel systems for laser plasma accelerators

  Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment · 2025-05-21 · 1 citations

  articleOpen accessSenior author
  PublisherOA PDFDOI

• A renewable double plasma mirror for Petawatt-class lasers

  Scientific Reports · 2025-07-01 · 3 citations

  articleOpen access

  Exceptional pulse contrast can be critical for ultraintense laser experiments, particularly when using solid density targets, and their use is becoming widespread. However, current plasma mirror technology is becoming inadequate for the new generation of high repetition rate, high power lasers now available. We describe a novel double plasma mirror configuration based on renewable, free standing, ultrathin liquid crystal films tested at the BELLA Petawatt Laser Center. Although operating at a repetition rate of several shots per minute, this system can be scaled to a high repetition rate exceeding 1 Hz and represents an important step towards enabling sustained, continuous operation of plasma mirrors. We demonstrate an improvement of two to three orders of magnitude in contrast and a total throughput of 80%. We present the first measurements of a beam reflected from a single or double plasma mirror system using a wavefront sensor, showing a well preserved wavefront and spatial mode. Finally, we introduce a model that predicts the total throughput through this double plasma mirror. This is the first model that accurately predicts the peak reflectivity of a plasma mirror when given the laser temporal profile.

  PublisherOA PDFDOI

• Modeling and design of compact, permanent-magnet transport systems for highly divergent, broad energy spread laser-driven proton beams

  Physical Review Accelerators and Beams · 2025-03-13 · 1 citations

  articleOpen access

  Laser-driven (LD) ion acceleration has been explored in a newly constructed short focal length laser beamline at the BELLA petawatt facility (interaction point 2, iP2). For applications utilizing such LD ion beams, a beam transport system is required, which for reasons of compactness be ideally contained within 3 m. While they are generated from a micron-scale source, large divergence and energy spread of LD ion beams present a unique challenge to transporting them compared to beams from conventional accelerators. This study gives an overview of proposed compact transport designs using permanent magnets satisfying different requirements depending on the application for the iP2 laser beamline such as radiation biology, material science, and high-energy density science. These designs are optimized for different parameters such as energy spread and peak proton density according to the application’s need. The various designs consist solely of permanent magnet elements, which can provide high magnetic field gradients on a small footprint. While the field strengths are fixed, we have shown that the beam size is able to be tuned effectively by varying the placement of the magnets. The performance of each design was evaluated based on high-order particle tracking simulations of typical LD proton beams. We also examine the ability of certain configurations to tune and select beam energies, critical for specific applications. A more detailed investigation was carried out for a design to deliver 10 MeV LD accelerated ions for radiation biology applications. With these transport system designs, the iP2 laser beamline is ready to house various application experiments.

  PublisherDOI

Frequent coauthors

• Wim Leemans

  Deutsches Elektronen-Synchrotron DESY

  1229 shared

• E. Esarey

  695 shared

• Eric Esarey

  470 shared

• Csaba Tóth

  415 shared

• C. G. R. Geddes

  409 shared

• J. van Tilborg

  375 shared

• K. Nakamura

  332 shared

• A. J. Gonsalves

  Lawrence Berkeley National Laboratory

  281 shared

Education

• PhD, Physics

  University of California, Berkeley

  1999

• BS, Mathematics

  University of Maryland, College Park

  1994

• BS, Physics

  University of Maryland, College Park

  1994

Awards & honors

• Fellow, American Physical Society (Division of Plasma Physic…
• John Dawson Award for Excellence in Plasma Physics Research,…
• Lawrence Berkeley National Laboratory Outstanding Performanc…
• Lawrence Berkeley National Laboratory Outstanding Performanc…