NAPAC2022 - List of Authors (Neveu, N.R.)

Paper

Title

Page

Commissioning of HOM Detectors in the First Cryomodule of the LCLS-II Linac

69

J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
B.T. Jacobson, N.R. Neveu, J.P. Sikora
SLAC, Menlo Park, California, USA

Long-range wakefields (LRWs) may cause emittance dilution effects. LWRs are especially unwanted at facilities with low emittance beams like the LCLS-II at SLAC. Dipolar higher-order modes (HOMs) are a set of LRWs that are excited by off-axis beams. Two 4-channel HOM detectors were built to measure the beam-induced HOM signals for TESLA-type superconducting RF (SRF) cavities; they were tested at the Fermilab Accelerator Science and Technology (FAST) facility and are now installed at SLAC. The HOM detectors were designed to investigate LRW effects on the beam and to help with beam alignment. This paper presents preliminary results of HOM measurements at the first cryomodule (CM01) of the LCLS-II linac and describes the relevant hardware and setup of the experiment.

DOI •

reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA12

About •

Received ※ 09 August 2022 — Accepted ※ 20 August 2022 — Issue date ※ 31 August 2022

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TUYE5

Multiobjective Optimization of the LCLS-II Photoinjector

N.R. Neveu
SLAC, Menlo Park, California, USA
T.H. Chang, S.T.P. Hudson, J.M. Larson
ANL, Lemont, Illinois, USA
P.L. Franz
Stanford University, Stanford, California, USA

Genetic algorithms and particle swarm optimization are currently the most widely used optimization algorithms in the accelerator physics community. These algorithms can take many evaluations to find optimal solutions for one machine prototype. In this work, the LCLS-II photoinjector is optimized with three optimization algorithms: a genetic algorithm, a surrogate based algorithm, and a multi-start scalarization method. All three algorithms were able to optimize the photoinjector, with various trade-offs for each method discussed here.

Slides TUYE5 [3.919 MB]

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FRXD5

Nonlinearly Shaped Pulses at LCLS-II

N.R. Neveu, S. Carbajo, Y. Ding, J.P. Duris, R.A. Lemons, A. Marinelli, J. Tang
SLAC, Menlo Park, California, USA

Funding: DOE
With the goal of improving emittance and longitudinal phase space of the electron beam, we consider nonlinear shaping of the temporal laser profile at the cathode. The operational Ultraviolet (UV) optics installed at the LCLS and LCLS-II currently produce Gaussian shaped pulses. Our simulations show the potential to reduce emittance and increase peak brightness when comparing nonlinear UV laser shapes on the cathode to baseline Gaussian pulses at the cathode.

Slides FRXD5 [3.597 MB]

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Paper	Title	Page
MOPA12	Commissioning of HOM Detectors in the First Cryomodule of the LCLS-II Linac	69
	J.A. Diaz Cruz UNM-ECE, Albuquerque, USA B.T. Jacobson, N.R. Neveu, J.P. Sikora SLAC, Menlo Park, California, USA
	Long-range wakefields (LRWs) may cause emittance dilution effects. LWRs are especially unwanted at facilities with low emittance beams like the LCLS-II at SLAC. Dipolar higher-order modes (HOMs) are a set of LRWs that are excited by off-axis beams. Two 4-channel HOM detectors were built to measure the beam-induced HOM signals for TESLA-type superconducting RF (SRF) cavities; they were tested at the Fermilab Accelerator Science and Technology (FAST) facility and are now installed at SLAC. The HOM detectors were designed to investigate LRW effects on the beam and to help with beam alignment. This paper presents preliminary results of HOM measurements at the first cryomodule (CM01) of the LCLS-II linac and describes the relevant hardware and setup of the experiment.
DOI •	reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOPA12
About •	Received ※ 09 August 2022 — Accepted ※ 20 August 2022 — Issue date ※ 31 August 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUYE5	Multiobjective Optimization of the LCLS-II Photoinjector
	N.R. Neveu SLAC, Menlo Park, California, USA T.H. Chang, S.T.P. Hudson, J.M. Larson ANL, Lemont, Illinois, USA P.L. Franz Stanford University, Stanford, California, USA
	Genetic algorithms and particle swarm optimization are currently the most widely used optimization algorithms in the accelerator physics community. These algorithms can take many evaluations to find optimal solutions for one machine prototype. In this work, the LCLS-II photoinjector is optimized with three optimization algorithms: a genetic algorithm, a surrogate based algorithm, and a multi-start scalarization method. All three algorithms were able to optimize the photoinjector, with various trade-offs for each method discussed here.
	Slides TUYE5 [3.919 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXD5	Nonlinearly Shaped Pulses at LCLS-II
	N.R. Neveu, S. Carbajo, Y. Ding, J.P. Duris, R.A. Lemons, A. Marinelli, J. Tang SLAC, Menlo Park, California, USA
	Funding: DOE With the goal of improving emittance and longitudinal phase space of the electron beam, we consider nonlinear shaping of the temporal laser profile at the cathode. The operational Ultraviolet (UV) optics installed at the LCLS and LCLS-II currently produce Gaussian shaped pulses. Our simulations show the potential to reduce emittance and increase peak brightness when comparing nonlinear UV laser shapes on the cathode to baseline Gaussian pulses at the cathode.
	Slides FRXD5 [3.597 MB]
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)