| Paper | Title | Page |
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| THPOTK059 | Laser System for SuperKEKB RF Gun in Phase III Commissioning | 2914 |
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| In order to generate high quality electron beam with high charge in Phase III commissioning of SuperKEKB, some improvements have been done in Ytterbium doped fiber and Neodymium doped YAG (Nd:YAG) hybrid laser system. Spatial reshaping part for the 4th harmonic laser beam at 266 nm has been adopted to realize low emittance electron beam. In addition, for achieving continuous and stable laser operation, position feedback system has also been used to improve the pointing stability of laser beam. In 2021 commissioning of SuperKEKB, stable 2 nC electron beam is generated for high energy ring (HER) injection. Meanwhile, we achieved the best emittance results at B-sector of linac injector and BT line for comparable low injection background and higher injection efficiency. With the aim of generating higher charge electron beam with good quality in the following commissioning, a perspective towards the next step update for current laser system is also introduced. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK059 | |
| About • | Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 04 July 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |
| THPOTK061 | Machine Learning Approach to Temporal Pulse Shaping for the Photoinjector Laser at CLARA | 2917 |
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| The temporal profile of the electron bunch is of critical importance in accelerator areas such as free-electron lasers and novel acceleration. In FELs, it strongly influences factors including efficiency and the profile of the photon pulse generated for user experiments, while in novel acceleration techniques it contributes to enhanced interaction of the witness beam with the driving electric field. Work is in progress at the CLARA facility at Daresbury Laboratory on temporal shaping of the ultraviolet photoinjector laser, using a fused-silica acousto-optic modulator. Generating a user-defined (programmable) time-domain target profile requires finding the corresponding spectral phase configuration of the shaper; this is a non-trivial problem for complex pulse shapes. Physically informed machine learning models have shown great promise in learning complex relationships in physical systems, and so we apply machine learning techniques here to learn the relationships between the spectral phase and the target temporal intensity profiles. Our machine learning model extends the range of available photoinjector laser pulse shapes by allowing users to achieve physically realisable configurations for arbitrary temporal pulse shapes. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK061 | |
| About • | Received ※ 30 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 03 July 2022 | |
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| THPOTK062 | Thermal Modeling and Benchmarking of Crystalline Laser Amplifiers | 2921 |
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Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231. Ti:sapphire crystals constitute the lasing medium of a class of lasers valued for their wide tunability and ultra-short, ultra-high intensity pulses. When operated at high power and high repetition rate (1kHz), such lasers experience multiple effects that can degrade performance. In particular, thermal gradients induce a spatial variation in the index of refraction, hence thermal lensing*. Using the open-source finite-element code FEniCS***, we solve the relevant partial differential equations to obtain a quantitative measure of the disruptive effects of thermal gradients on beam quality. We present thermal simulations of a pump laser illuminating a Ti:sapphire crystal. From these simulations we identify the radial variation in the refractive index, and hence the extent of thermal lensing. In addition, we present analytic models used to estimate the effect of thermal gradients on beam quality. This work generalizes to other types of crystal amplifiers. * S. Cho, et al., Appl. Phys. Express, 11:092701, 2018. ** M. Born & E. Wolf, Principles of Optics, Cambridge Univ. Press, 1980. *** The FEniCS computing platform, https://fenicsproject.org |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK062 | |
| About • | Received ※ 13 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022 | |
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| THPOTK063 | Open Source Software to Simulate Ti:Sapphire Amplifiers | 2925 |
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Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231. The design of next-generation PW-scale fs laser systems, including scaling to kHz rates and development of new laser gain media for efficiency, will require parallel multiphysics simulations with realistic errors and nonlinear optimization. There is currently a lack of broadly available modeling software that self-consistently captures the required physics of gain, thermal loading and lensing, spectral shaping, and other effects required to quantitatively design such lasers.* We present initial work towards an integrated multiphysics capability for modeling pulse amplification in Ti:Sa lasers. All components of the software suite are open source. The Synchrotron Radiation Workshop (SRW)** is being used for physical optics, together with Python utilities. The simulations are being validated against experiments. * R. Falcone et al., Brightest Light Initiative Workshop Report (2019). ** https://github.com/ochubar/srw |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK063 | |
| About • | Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022 | |
| Cite • | reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml) | |