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Stupakov, Gennady

Publications and source records attributed to Stupakov, Gennady.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

The EIC accelerator: design highlights and project status

The design of the electron-ion collider (EIC) at Brookhaven National Laboratory is well underway, aiming at a peak electron-proton luminosity of 10e+34 cm^-1·sec^-1. This high luminosity, the wide center-of-mass energy range from 29 to 141 GeV (e-p) and the high level of polarization require innovative solutions to maximize the performance of the machine, which makes the EIC one of the most challenging accelerator projects to date. The complexity of the EIC will be discussed, and the project status and plans will be presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Design Status of the Electron-Ion Collider

The Electron-Ion Collider is gearing up for "Critical Decision 2", theproject baseline with defined scope, cost and schedule.Lattice designs are beingfinalized, and preliminary component design is being carried out. Beam dynamicsstudies such as dynamic aperture optimization, instability and polarizationstudies, and beam-beam simulations are continuing in parallel. We report onthe latest developments and the overall status of the project, and presentthe plans for future activities.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

Cooling and diffusion rates in coherent electron cooling concepts

We present analytic cooling and diffusion rates for a simplified model of coherent electron cooling (CEC), based on a proton energy kick at each turn. This model also allows to estimate analytically the rms value of electron beam density fluctuations in the "kicker" section. Having such analytic expressions should allow for better understanding of the CEC mechanism, and for a quicker analysis and optimization of main system parameters. Our analysis is applicable to any CEC amplification mechanism, as long as the wake (kick) function is available.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Estimate of Joule Heating in a Flat Dechirper

We have performed Joule power loss calculations for a flat dechirper. We have considered the configurations of the beam on-axis between the two plates—for chirp control—and for the beam especially close to one plate—for use as a fast kicker. Our calculations use a surface impedance approach, one that is valid when corrugation parameters are small compared to aperture (the perturbative parameter regime). In our model we ignore effects of field reflections at the sides of the dechirper plates, and thus expect the results to underestimate the Joule losses. The analytical results were also tested by numerical, time-domain simulations. We find that most of the wake power lost by the beam is radiated out to the sides of the plates. For the case of the beam passing by a single plate, we derive an analytical expression for the broad-band impedance, and—in Appendix B—numerically confirm recently developed, analytical formulas for the short-range wakes. While our theory can be applied to the LCLS-II dechirper with large gaps, for the nominal apertures we are not in the perturbative regime and the reflection contribution to Joule losses is not negligible. With input from computer simulations, we estimate the Joule power loss (assuming bunch charge of 300 pC, repetition rate of 100 kHz) is 21 W/m for the case of two plates, and 24 W/m for the case of a single plate.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Wakefields of a Beam near a Single Plate in a Flat Dechirper

At linac-based, X-ray free electron lasers (FELs), there is interest in streaking the beam by inducing the transverse wakes in a flat dechirper, by passing the beam near to one of its two jaws. For LCLS-II - as has already been done for LCLS-I - this way of using the dechirper will e.g. facilitate two-color and fresh slice schemes of running the FEL. With the beam a distance from the near wall of say b ~ 0.25 mm and from the far wall by ≳ 5 mm, the second wall will no longer affect the results. The physics will be quite different from the two plate case: with two plates the impedance has a resonance spike whose frequency depends on the plate separation 2a; in the single plate case this parameter no longer exists. Formulas for the longitudinal, dipole, and quadrupole wakes for a beam off-axis between two dechirper plates, valid for the range of bunch lengths of interest in an X-ray FEL, are given in reference 3. By taking the proper limit, we can obtain the corresponding wakes for a beam close to one dechirper plate and far from the other. This is the task we perform in this note.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Dispersion relation of a surface wave at a rough metal-air interface

Here, we derived a dispersion relation of a surface wave at a rough metal-air interface. In contrast to previous publications, we assumed that an intrinsic surface impedance due to a finite electric conductivity of the metal can be of the same order as the roughness-induced impedance. We then applied our results to the analysis of a long-standing problem of the discrepancy between the experimental data on the propagation of surface waves in the terahertz range of frequencies and the classical Drude theory.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Measurements of terahertz radiation generated using a metallic, corrugated pipe

Here, a method for producing narrow-band THz radiation proposes passing an ultra-relativistic beam through a metallic pipe with small periodic corrugations. We present results of a measurement of such an arrangement at Brookhaven's Accelerator Test Facility (ATF). Our pipe was copper and was 5 cm long; the aperture was cylindrically symmetric, with a 1 mm (radius) bore and a corrugation depth (peak-to-peak) of 60 µm. In the experiment we measured both the effect on the beam of the structure wakefield and the spectral properties of the radiation excited by the beam. We began by injecting a relatively long beam compared to the wavelength of the radiation, but with short rise time, to excite the structure, and then used a downstream spectrometer to infer the radiation wavelength. This was followed by injecting a shorter bunch, and then using an interferometer (also downstream of the corrugated pipe) to measure the spectrum of the induced THz radiation. For the THz pulse we obtain and compare with calculations: the central frequency, the bandwidth, and the spectral power—compared to a diffraction radiation background signal.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗