20th Advanced Accelerator Concepts Workshop

6 Nov 2022, 15:00 → 11 Nov 2022, 17:10 America/New_York

Hyatt Regency Long Island

Mark Palmer (Brookhaven National Laboratory) , Navid Vafaei-Najafabadi (Stony Brook University)

The AAC’22 workshop is the 20th in a series of by-invitation biennial fora for intensive discussions on long-term research in advanced accelerator physics and technology. This research supports the development of capabilities for the basic sciences, from photon science to high energy physics, as well as the development of compact accelerators for industrial, medical and security applications.

AAC'22 will be organized into eight working groups covering the following topical areas:

1. Laser-Plasma Wakefield Acceleration 
2. Computation for Accelerator Physics
3. Laser and High-Gradient Structure-Based Acceleration
4. Beam-Driven Acceleration
5. Beam Sources, Monitoring, and Control
6. Laser-Plasma Acceleration of Ions
7. Radiation Generation and Advanced Concepts
8. Advanced Laser and Beam Technology and Facilities

Conference Home:  https://www.aac2022.org/

 

Sunday, 6 November

18:00 → 19:30 Welcome Reception

Monday, 7 November

10:20 → 10:40 Coffee Break

12:10 → 13:30 Lunch

15:00 → 15:30 Coffee Break

Tuesday, 8 November

10:00 → 10:30 Coffee Break

12:00 → 13:20 Lunch

15:00 → 15:30 Coffee Break/Exhibits

Wednesday, 9 November

10:00 → 10:30 Coffee Break/Exhibits

12:00 → 13:20 Lunch

13:30 → 15:00 WGs 1+8 Joint Session: Session 1 of 1

Joint session between Working Groups 1 & 8:
WG1 - Laser-Plasma Wakefield Acceleration
WG8 - Advanced Laser and Beam Technology and Facilities

Conveners: Irina Petrushina (Stony Brook University) , Mr Marcus Babzien (BNL) , Marlene Turner (LBNL) , Stephen Milton, Yong Ma (University of Michigan)

13:30 High-efficiency and high-quality laser-plasma accelerator stages for a plasma-based linear collider

The viability of next generation plasma-based linear colliders relies on the possibility of accelerating high-charge and low-emittance bunches to high energies over short distances with high efficiency, while keeping a small relative energy spread. Laser-plasma accelerators (LPAs) can operate in different regimes, namely, linear (or mildly nonlinear) stages, where laser guiding is achieved by means of an external waveguide such as a plasma channel, or nonlinear stages where the laser is self-guided through the plasma by means of relativistic self-focusing and plasma wave guiding. For the same laser driver energy, channel-guided and self-guided LPA stages are characterized by different accelerating gradients, lengths, optimal bunch parameters, and acceleration efficiencies. In this talk we present a systematic investigation of the properties of channel-guided and self-guided LPAs with fixed laser energy, and we discuss a self-guided LPA stage operating in the nonlinear regime providing high-gradient, high-efficiency, and quality-preserving acceleration of electron beams for collider applications.

Speaker: Carlo Benedetti (LBNL)

13:50 Spatial temporal couplings and the generation of Stimulated Raman Side Scattering

We report on experiments investigating the influence of spatio-temporal couplings (STCs) in the laser focus on stimulated Raman Side Scattering. We find a discrepancy between measured scattered angles and classical theory. At the same time, the angle changes with propagation of the driving laser pulse. This mismatch can be resolved if the pulse front tilt (PFT) of the laser pulse is taken into account. We developed an analytic model to describe the propagation of a Gaussian laser pulse exhibiting first order STC around the focal plane, which describes the observed behaviour. Using 2D-PIC Simulations we can reproduce the experimental results and observe phase matching between the driving pump pulse, the plasma k-vectors and the scattered light. As a result, the PFT of a laser pulse excites larger plasma k-vectors, which leads to a larger scattering angle.

Speaker: Alexander Sävert (Helmholtz Institute Jena)

14:10 The BELLA PW iP2&2BL Upgrades – Radiation and Laser Safety considerations and implementations for safe and efficient user experiments

After a decade-long successful operations [1] and producing new results in the field of Laser Plasma Acceleration (LPA) research [2-4] by the Berkeley Lab Laser Accelerator (BELLA), the PW laser system’s recent upgrades were completed in 2022. The first is the “Second Beamline” (PW-2BL), where the fully amplified, stretched pulses are split before compression, enabling two independently adjustable laser pulses to interact with a variety of target arrangements in one target chamber with up to ~40 J total energy. The new BELLA PW 2BL provides the opportunity to conduct the next generation of LPA experiments, such as staging, laser-driven waveguides for increased electron energy, and positron acceleration. The other upgrade is labeled as “Interaction Point #2” (PW-iP2) [5], in which the already compressed PW laser pulses of the original beamline are transported (via a 1:1 reflective telescope using two long focal length OAPs) to a new target chamber allowing a short focal length (0.5 m) arrangement resulting in a small focal spot in the order of ~ 3 um and high laser intensity of >5×10^21 W/cm^2.
An overview of the special considerations, planning and implementation processes related to radiation shielding, laser and radiation interlock systems required for the safe and efficient operation of the new BELLA PW beamlines and conduction of the planned experiments will be presented. Specific topics include: analysis of hazards, development of appropriate hazard mitigation strategies, design details of new shielding components, radiation field monitoring, and interlocked radiation detector and laser beam shutter systems, conditions for high power operations – all matched to the expected particle beam parameters in new experiments.
This work was supported by the U.S. Department of Energy Office of Science, Offices of High Energy Physics and Fusion Energy Sciences under Contract No. DE-AC02–05CH11231. Commissioning experiments for iP2 are supported by LaserNetUS.

[1] K. Nakamura et al., IEEE J. QE 53, 1200121 (2017).
[2] W.P. Leemans et al., Phys. Rev. Letters 113, 245002 (2014).
[3] A.J. Gonsalves et al., Phys. Rev. Letters 122, 84801 (2019).
[4] S. Steinke et al., PRAB 23, 021302 (2020).
[5] S. Hakimi et al., Phys. Plasmas 29, 083102 (2022).

Speaker: Csaba Toth (Lawrence Berkeley National Laboratory)

BELLA PW Upgrades -WG8 -Toth.pdf

14:30 Updates and Commissioning results of the Second Beamline Upgrade to BELLA PW

The petawatt (PW) facility at Berkeley Lab Laser Accelerator (BELLA Center) has successfully performed several experiments since its installation in 2012 [1], primarily focusing on optimization of single stage, high energy gain laser-plasma accelerators (LPAs) [2,3]. Recently, the facility has undergone two significant upgrades: i) a new second beamline (2BL) delivered into the existing experimental chamber, and ii) a new experimental chamber providing capabilities for experiments in tightly focused geometries [4]. This talk focuses on the installation of the new second beamline. To form this, the PW laser pulse is split before compression, and passed through a new compressor chamber, making it capable of delivering up to 500 TW at 1 Hz, synchronous with the existing beamline (1BL). Currently installed is a f=13.5m off-axis parabola, matching the existing beamline, although focusing optics ranging from f=18.5m to short focal length geometries are possible. We show results from low- and high-power commissioning of 2BL, demonstrating temporal compression to 37 fs, high quality focal mode (measured Strehl ratio ≳ 0.8), and good shot-to-shot timing stability between 1BL and 2BL (RMS jitter of 8 fs). We outline plans for three upcoming dual-beam campaigns made possible by this upgrade: staging of 2 LPAs; PW guiding in optically formed plasma channels; and two-color ionization injection.

[1] Nakamura, Kei, et al., IEEE Journal of Quantum Electronics 53.4 (2017): 1-21. (https://doi.org/10.1109/JQE.2017.2708601)

[2] Leemans, W. P., et al., Physical Review Letters 113.24 (2014): 245002. (https://doi.org/10.1103/PhysRevLett.113.245002)

[3] Gonsalves, A. J., et al., Physical Review Letters 122.8 (2019): 084801. (https://doi.org/10.1103/PhysRevLett.122.084801)

[4] Hakimi, Sahel, et al., Physics of Plasmas 29.8 (2022): 083102. (https://doi.org/10.1063/5.0089331)

Speaker: Alex Picksley (Lawrence Berkeley National Laboratory)

Thursday, 10 November

10:00 → 10:30 Coffee Break/Exhibits

12:00 → 13:20 Lunch

15:00 → 18:00 Afternoon at Leisure

Friday, 11 November

10:00 → 10:30 Coffee Break

12:00 → 13:00 Lunch

14:40 → 15:00 Coffee Break