Spencer Gessner
A5030514894- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Particle Detector Development and Performance
- Atomic and Molecular Physics
- Particle physics theoretical and experimental studies
- Plasma Diagnostics and Applications
- Pulsed Power Technology Applications
- Laser-induced spectroscopy and plasma
- Gyrotron and Vacuum Electronics Research
- Nuclear Physics and Applications
- Laser-Matter Interactions and Applications
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Ion-surface interactions and analysis
- Electron and X-Ray Spectroscopy Techniques
- Ionosphere and magnetosphere dynamics
- Distributed and Parallel Computing Systems
- Muon and positron interactions and applications
- Superconducting Materials and Applications
- Crystallography and Radiation Phenomena
- Dust and Plasma Wave Phenomena
- Advanced X-ray Imaging Techniques
- Medical Imaging Techniques and Applications
SLAC National Accelerator Laboratory
2016-2025
University of Oslo
2024
Menlo School
2013-2023
Stanford University
2011-2023
European Organization for Nuclear Research
2017-2022
Linac Coherent Light Source
2014-2022
Campbell Collaboration
2020-2022
Stony Brook University
2019
Google (United States)
2019
Los Alamos National Laboratory
2015
High energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. In order to increase or reduce size accelerator, new acceleration schemes need be developed. Plasma wakefield acceleration, which electrons plasma are excited, leading strong electric fields, is one such promising novel technique. Pioneering experiments shown an intense laser pulse electron bunch traversing plasma, drives fields 10s...
Abstract Plasma wakefield accelerators have been used to accelerate electron and positron particle beams with gradients that are orders of magnitude larger than those achieved in conventional accelerators. In addition being accelerated by the plasma wakefield, beam particles also experience strong transverse forces may disrupt quality. Hollow channels proposed as a technique for generating accelerating fields without forces. Here we demonstrate method creating an extended hollow channel...
The International Linear Collider (ILC) is on the table now as a new global energy-frontier accelerator laboratory taking data in 2030s. ILC addresses key questions for our current understanding of particle physics. It based proven technology. Its experiments will challenge Standard Model physics and provide window to look beyond it. This document brings story up date, emphasizing its strong motivation, readiness construction, opportunity it presents US community.
During the past two decades of research, ultra-relativistic beam-driven plasma wakefield accelerator (PWFA) concept has achieved many significant milestones. These include demonstration ultra-high gradient acceleration electrons over meter-scale structures, efficient a narrow energy spread electron bunch at high-gradients, positron using wakes in uniform plasmas and hollow channels, demonstrating that highly nonlinear 'blow-out regime' have electric field structure necessary for preserving...
We give direct experimental evidence for the observation of full transverse self-modulation a long, relativistic proton bunch propagating through dense plasma. The exits plasma with periodic density modulation resulting from radial wakefield effects. show that is seeded by ionization front created using an intense laser pulse copropagating bunch. extends over length following seed point. By varying one order magnitude, we frequency scales expected dependence on density, i.e., it equal to...
The seeded self-modulation of a relativistic, charged particle bunch in plasma is shown to grow both along the and plasma, resulting transverse wakefield amplitudes that far exceed initial seed values.
Abstract Colliders are essential research tools for particle physics. Numerous future collider proposal were discussed in the course of US high energy physics community strategic planning exercise Snowmass'21 . The Implementation Task Force (ITF) has been established to evaluate proposed accelerator projects performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics developed uniform comparison proposals ranging from Higgs/EW factories multi-TeV...
Plasma acceleration has emerged as a promising technology for future particle accelerators, particularly linear colliders. Significant progress been made in recent decades toward high-efficiency and high-quality of electrons plasmas. However, this does not generalize to positrons, plasmas are inherently charge asymmetric. Here, we present comprehensive review historical current efforts accelerate positrons using plasma wakefields. Proposed schemes that aim increase the energy efficiency beam...
AWAKE is a proton-driven plasma wakefield acceleration experiment. % We show that the experimental setup briefly described here ready for systematic study of seeded self-modulation 400\,GeV proton bunch in 10\,m-long rubidium with density adjustable from 1 to 10$\times10^{14}$\,cm$^{-3}$. short laser pulse used ionization vapor propagates all way along column, suggesting full vapor. occurs bunch, at time and follows affects bunch.
Plasma wakefield acceleration is a promising technology to reduce the size of particle accelerators. The use high energy protons drive wakefields in plasma has been demonstrated during Run 1 AWAKE programme at CERN. Protons 400 GeV drove that accelerated electrons 2 under 10 m plasma. collaboration now embarking on with main aims demonstrate stable accelerating gradients 0.5–1 GV/m, preserve emittance electron bunches and develop sources scalable 100s metres beyond. By end 2, scheme should...
The HALHF collaboration has discussed a new baseline for the project, taking into account comments from accelerator community on various aspects of original design. In particular, these concerned practicality dual-purpose linac to accelerate both colliding positron bunches and drive beams required plasma linac. addition, many other project were also considered; discussion conclusions are documented in this paper. Finally, is outlined that been optimised addresses several weaknesses design,...
In this Letter, we report on the experimental generation of high energy (10 GeV), ultrashort (femtosecond-duration), ultrahigh current (∼0.1 MA), petawatt peak power electron beams in a particle accelerator. These extreme enable exploration new frontier high-intensity beam-light and beam-matter interactions broadly relevant across fields ranging from laboratory astrophysics to strong field quantum electrodynamics ultrafast chemistry. We demonstrate our ability generate control properties...
This document outlines a community-driven Design Study for 10 TeV pCM Wakefield Accelerator Collider. The 2020 ESPP Report emphasized the need Advanced R\&D, and 2023 P5 calls ``delivery of an end-to-end design concept, including cost scales, with self-consistent parameters throughout." leverages recent experimental theoretical progress resulting from global R\&D program in order to deliver unified, Collider concept. Accelerators provide ultra-high accelerating gradients which enables...
We report on an experiment performed at the Facility for Advanced Accelerator Experimental Tests (FACET) SLAC National Laboratory, in which a new adaptive control algorithm, one with known, bounded update rates, despite operating analytically unknown cost functions, was utilized order to provide quasi-real-time bunch property estimates of electron beam. Multiple parameters, such as arbitrary rf phase settings and other time-varying accelerator properties, were simultaneously tuned match...
Hollow channel plasma wakefield acceleration is a proposed method to provide high gradients for electrons and positrons alike: key future lepton colliders. However, beams which are misaligned from the axis induce strong transverse wakefields, deflecting reducing collider luminosity. This undesirable consequence sets tight constraint on alignment accuracy of beam propagating through channel. Direct measurements misalignment-induced wakefields therefore essential designing mitigation...
An electron beam has gained a maximum energy of 9 GeV per particle in 1.3 m-long beam-driven plasma wakefield accelerator. The amount charge accelerated the spectral peak was 28.3 pC, and root-mean-square spread 5.0%. mean gain 215 shot data set 115 pC 5.3 GeV, respectively, corresponding to an acceleration gradient 4.0 GeV/m at peak. 5.1%. These results are consistent with extrapolation previously reported using shorter, 36 cm-long source within 10%, evincing non-evolving wake structure...
Abstract Laser-plasma accelerators are capable of sustaining accelerating fields 10–100 GeV/m, 100–1000 times that conventional technology and the highest produced by any widely researched advanced accelerator concepts. also intrinsically accelerate short particle bunches, several orders magnitude shorter than technology, which leads to reductions in beamstrahlung and, hence, savings overall power consumption reach a desired luminosity. These properties make laser-plasma promising for more...
High gradients of energy gain and high efficiency are necessary parameters for compact, cost-efficient high-energy particle colliders. Plasma Wakefield Accelerators (PWFA) offer both, making them attractive candidates next-generation In these devices, a charge-density plasma wave is excited by an ultra-relativistic bunch charged particles (the drive bunch). The in the can be extracted second trailing bunch), as this propagates wake bunch. While electron was accelerated with more than...
The Facility for Advanced Accelerator and Experimental Tests (FACET) at SLAC installed a 10-TW Ti : sapphire laser system pre-ionized plasma wakefield acceleration experiments. High energy (500 mJ), short (50 fs) pulses of 800 nm light 1 Hz are used the FACET experimental area to produce column. stretched 250 fs before injection into vapor cell, where is focused by an axicon lens form column that can be sustained over desired radius length. A 20 GeV electron bunch interacts with this...
Abstract High repetition rates and efficient energy transfer to the accelerating beam are important for a future linear collider based on beam-driven plasma wakefield acceleration scheme (PWFA-LC). This paper reports first results from Plasma Wakefield Acceleration Collaboration (E300) that beginning address both of these issues using recently commissioned FACET-II facility at SLAC national accelerator laboratory. We have generated meter-scale hydrogen plasmas time-structured 10 GeV electron...