First Name: H
Middle Name:
Last Name: Suk
Full Name: Suk, H.
tags:
view citation format
16 papers
| title: | Plasma density transition trapping as a possible high-brightness electron beam source |
| format: | journal article |
| year: | 2004 |
| 3 authors: | | | |
| abstract: | Plasma density transition trapping is a recently proposed self-injection scheme for plasma wakefield accelerators. This technique uses a sharp downward plasma density transition to trap and accelerate background plasma electrons in a plasma wakefield. This paper examines the quality of electron beams captured using this scheme in terms of emittance, energy spread, and brightness. Two-dimensional particle-in-cell simulations show that these parameters can be optimized by manipulating the plasma density profile.We also develop, and support with simulations, a set of scaling laws that predicts how the brightness of transition trapping beams scales with the plasma density of the system. These scaling laws indicate that transition trapping can produce beams with brightness > 5 x 10^14 A/(mrad)^2. A proof-of principle transition trapping experiment is planned for the near future. The proposed experiment is described in detail. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Dynamics of a Driver Beam Propagating in an Underdense Plasma with a Downward Density Transition |
| format: | conference procceeding |
| conference: | 2001 Particle Accelerator Conference |
| year: | 2001 |
| 7 authors: | | | | | | | |
| abstract: | When a short electron beam propagates in an underdense plasma (plasma density n_p < beam density n_b) with a downward density transition, it is known that some background plasma electrons are trapped and accelerated by the plasma wakefield[1]. Beam quality of the trapped plasma electrons is severely affected by the wakefield that is generated by the driving electron beam, so dynamics and instabilities of the driver beam are very important. In this paper, we present some simulation results on the self-trapping and driver beam dynamics. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Beam-plasma interaction experiments at the UCLA Neptune Laboratory |
| format: | conference procceeding |
| conference: | 2001 Particle Accelerator Conference |
| year: | 2001 |
| 5 authors: | | | | | |
| abstract: | We are currently planning several beam-plasma interaction experiments using the high quality 16 MeV electron beam produced by the Neptune 1.625-cell photoinjector and PWT linac. The underdense (n_b > n_0) plasma lens experiment will examine the focusing of a 4 nC beam of 30 psec pulse duration as it passes through a thin 2 cm Ar plasma lens. We are also developing a negative R_56 compressor beamline that will allow us to create ramped sub-picosecond beams of a shape well suited for driving large amplitude plasma wake fields and producing high transformer ratios. Simulations made using the 2-1/2 dimensional particle-in-cell code MAGIC indicate that we could use these ramped beams to produce fields of up to 10 GeV/m in a 10(16) cm(-3) plasma. Ramped beams are also suitable for driving plasma density gradient trapping experiments. When such a beam passes through a region where the plasma density drops suddenly the fast variation of the wake fields traps several pC of plasma electrons in the accelerating portion of the wake field. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Plasma Electron Trapping and Acceleration in a Plasma Wake Field Using a Density Transition |
| format: | journal article |
| year: | 2001 |
| 4 authors: | | | | |
| abstract: | A new scheme for plasma electron injection into an acceleration phase of a plasma wake field is presented. In this scheme, a single, short electron pulse travels through an underdense plasma with a sharp, localized, downward density transition. Near this transition, a number of background plasma electrons are trapped in the plasma wake field, due to the rapid wavelength increase of the induced wake wave in this region. The viability of this scheme is verified using two-dimensional particle-in-cell simulations. To investigate the trapping and acceleration mechanisms further, a 1D Hamiltonian analysis, as well as 1D simulations, has been performed, with the results presented and compared. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Commissioning and measurements of the Neptune photo-injector |
| format: | conference procceeding |
| conference: | 9th Advanced Accelerator Concepts Workshop |
| year: | 2001 |
| 6 authors: | | | | | | |
| abstract: | The photo-injector for the Neptune Advanced Accelerator Laboratory is introduced. Its component parts, including the radio frequency gun, photo-cathode drive laser system, booster linac, RF system, chicane compressor, beam diagnostics, and control system are described. The injector is designed to produce high brightness, short pulse electron beams. Measurements of the photo-injector beams including quantum efficiency, emittance, pulse length, and pulse compression are presented. (21 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Trapping of background plasma electrons in a beam-driven plasma wake field using a downward density transition |
| format: | conference procceeding |
| conference: | 9th Advanced Accelerator Concepts Workshop |
| year: | 2001 |
| 4 authors: | | | | |
| abstract: | Trapping of background plasma electrons by a beam-driven plasma wake field is studied as a new self-injection method. In this scheme, a short electron beam pulse is sent through an underdense plasma with a downward density transition and some background plasma electrons are trapped by the strong wake field due to the sudden increase of the wake wave wavelength at the density transition. Two-dimensional PIC (Particle-In-Cell) simulations show that a significant amount of plasma electrons are trapped and accelerated to a higher energy than the driving beam energy. Furthermore, the trapped-beam quality is fairly good. In this paper, the 2-D simulation results, dynamics of the trapped beam and the driving beam, and the proposed experiment for the UCLA Neptune Laboratory are described. (15 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Commissioning of the Neptune Photoinjector |
| format: | conference procceeding |
| conference: | APS April Meeting |
| year: | 2000 |
| 13 authors: | | | | | | | | | | | | | |
| abstract: | The status of the commissioning of the rf photoinjector in the Neptune advanced accelerator laboratory is discussed. The component parts of the photoinjector, the rf gun, photocathode drive laser system, booster linac, rf system, chicane compressor, beam diagnostics systems, and control system are described. Recent improvements in the rf gun, rf timing, and chicane compressor systems are detailed. This injector is designed to produce short pulse length, high brightness electron beams. Experiments planned for the immediate future are described. Initial measurements of various beam parameters are presented. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Plasma Electron Trapping and Acceleration in a Plasma Wake Field Using a Density Transition |
| format: | preprint |
| year: | 2000 |
| 5 authors: | | | | | |
| abstract: | A new scheme for plasma electron injection into an acceleration phase of a plasma wakefield is presented. In this scheme, a short single electron beam bunch is sent through an underdense plasma with a sharp, localized downward density transition. Near this transition, a number of background plasma electrons are trapped in the plasma wake field due to the rapid wavelength increase of the wake wave in this region. The viability of this scheme is verified using two-dimensional particle-in-cell (PIC) simulations. To investigate the trapping and acceleration mechanism further, a 1-D Hamiltonian analysis as well as 1-D simulations have been performed, with the results are presented and compared. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Electron Beam Photocathode Cleaning |
| format: | conference procceeding |
| conference: | APS April Meeting |
| year: | 2000 |
| 7 authors: | | | | | | | |
| abstract: | We are experimenting with low energy electron beams as a means of cleaning and improving the quantum efficiency of metallic photocathodes. Electron beam surface cleaning has been used successfully in electron cooling devices at Fermilab (S. Nagaitsev) and Novosibirsk (A.N. Sharapa and A.V. Shemyakin). The cooling device data indicates that a 2 mA h/cm2 specific dose of 3 keV electrons on the surface of the photocathode will produce a surface with an outgas rate at least one order of magnitude lower than a 24 hour 400 |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Plasma source test and simulation results for the underdense plasma lens experiment at the UCLA Neptune Laboratory |
| format: | unknown |
| year: | 2000 |
| 8 authors: | | | | | | | | |
| abstract: | The planned plasma lens experiment at the UCLA Neptune Laboratory is described. In the experiment, electron beams with an energy of 16 MeV, a charge of 4 nC, and a pulse duration of 30 ps full-width at half-maximum (FWHM) are designed to be produced from the 1.625-cell photoinjector radio-frequency gun (f=2.856 GHz) and PWT linac in the Neptune. The generated beams are passed through a thin plasma with a density of low 10/sup 12/ cm/sup -3/ range and a thickness of a few centimeters. For this experiment, a LaB/sub 6/-based discharge plasma source was developed and tested. In this paper, the overview of the planned plasma lens experiment and the test results of the plasma source for various conditions are presented. In addition, computer simulations with a 2-1/2 dimensional particle-in-cell code (MAGIC) were performed and the simulation results are shown. (19 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Plasma electron trapping and acceleration in a plasma wake field using a density transition |
| format: | conference procceeding |
| conference: | 2nd ICFA Advanced Accelerator Workshop on the Physics of High Brightness Beams |
| year: | 2000 |
| 4 authors: | | | | |
| abstract: | A new scheme for plasma electron injection into an acceleration phase of a plasma wake field is presented. In this scheme, a short single electron beam bunch is sent through an underdense plasma with a sharp downward density transition and some plasma electrons are trapped in the plasma wake field due to the rapid wavelength increase of the wake wave at the density transition. To investigate the trapping and acceleration mechanism, two-dimensional particle-in-cell (PIC) simulations were performed, and the illustrative 2-D simulation shows that the new injection method can produce a relatively large charge (~0.5 nC), short (~1 ps) and high energy (> driving beam energy) electron beam pulse with a plasma density transition from 5x10(13) cm(-3) to 3.5x10(13) cm(-3). In addition to the 2-D simulations, 1-D analytic work based on the Hamiltonian formalism and 1D simulations have been performed and the results are also presented. Finally, a proposed experiment at the Neptune Laboratory of UCLA is described. |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Commissioning of the Neptune photoinjector |
| format: | conference procceeding |
| conference: | 1999 Particle Accelerator Conference |
| year: | 1999 |
| 21 authors: | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The status of the commissioning of the RF photoinjector in the Neptune advanced accelerator laboratory is discussed. The component parts of the photoinjector, the RF gun, photocathode drive laser system, booster linac, RF system, chicane compressor, beam diagnostics systems, and control system are described. This injector is designed to produce short pulse length, high brightness electron beams. Experiments planned for the immediate future are described. Initial measurements of various beam parameters are presented. (10 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Underdense plasma lens experiment at the UCLA Neptune Laboratory |
| format: | conference procceeding |
| conference: | 1999 Particle Accelerator Conference |
| year: | 1999 |
| 10 authors: | | | | | | | | | | |
| abstract: | An underdense plasma-lens experiment is planned at the UCLA Neptune Laboratory. For this experiment, a LaB/sub 6/-based discharge plasma source was developed and tested. Test results of the plasma source show that it can provide satisfactory Ar plasma parameters for underdense plasma lens experiments, i.e., a density in the low 10/sup 12/ cm/sup -3/ range and a thickness of a few cm. In the plasma chamber a YAG slab and a Cherenkov radiator are placed for electron beam diagnostics so that both time-integrated and time-resolved information will be obtained and compared with the MAGIC code (2 and 1/2 dimensional particle-in-cell) simulations. In this paper, the planned experiment including test results of the plasma source, diagnostics and MAGIC simulation results is presented. (5 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Test results of the plasma source for underdense plasma lens experiments at the UCLA Neptune Lab |
| format: | conference procceeding |
| conference: | 8th Advanced Accelerator Concepts Workshop |
| year: | 1999 |
| 7 authors: | | | | | | | |
| abstract: | A plasma source was developed at UCLA for planned underdense plasma lens experiments, where the plasma density is less than the electron beam density. The argon plasma, produced by a discharge between a LaB_6 cathode at 1330 degrees C and a tantalum anode, is confined by a solenoidal magnetic field and flows transversely across the electron beam path. Extensive test of the plasma source is under way for various conditions before it is assembled with the UCLA photocathode-based electron linac. In particular, different longitudinal (with respect to the electron beam) plasma profiles and effective plasma lengths can be obtained by adjusting the moveable sliding door between the plasma source and the transverse beamline. Test results of the plasma source are presented. (11 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | The Neptune photoinjector |
| format: | conference procceeding |
| conference: | ICFA Second Generation Plasma Acceleration Workshop |
| year: | 1998 |
| 12 authors: | | | | | | | | | | | | |
| abstract: | The RF photoinjector in the Neptune advanced accelerator laboratory, along with associated beam diagnostics, transport and phase-space manipulation techniques are described. This versatile injector has been designed to produce short-pulse electron beams for a variety of uses: ultra-short bunches for injection into a next-generation plasma beatwave acceleration experiment, space-charge dominated beam physics studies, plasma wake-field acceleration driver, plasma lensing, and free-electron laser microbunching techniques. The component parts of the photoinjector, the RF gun, photocathode drive laser systems, booster linac, RF system, chicane compressor, beam diagnostic systems, and control system, are discussed. The present status of photoinjector commissioning at Neptune is reviewed, and proposed experiments are detailed. (33 References). |
| keywords: | |
| Download | View | Details | edit | delete | |
| title: | Bunch length measurement of picosecond electron beams from a photoinjector using coherent transition radiation |
| format: | conference procceeding |
| conference: | ICFA Second Generation Plasma Acceleration Workshop |
| year: | 1998 |
| 6 authors: | | | | | | |
| abstract: | The bunch length of an electron beam derived from the UCLA Saturnus photoinjector has been measured using a 45 degrees CTR foil. The sudden change of electrons boundary conditions cause them to radiate (transition radiation) with the spectral power entirely dependent upon the degree of coherency, which strongly relates to the beam size. A polarizing Michelson interferometer allowed measurement of the auto-correlation of the coherent transition radiation signal. An analysis method was developed to compensate for undetected low-frequency radiation and systematically extract the bunch length information for a specific beam model. This analysis allowed observation of pulse lengthening due to the space charge, as well as compression with the variation of the RF injection phase. The hypothesis of a satellite beam has been also tested using this analysis. (8 References). |
| keywords: | |
| Download | View | Details | edit | delete | |