First Name: S.
Middle Name: G.
Last Name: Anderson
Full Name: S.G. Anderson
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7 papers
| title: | RF photoinjector development for a short-pulse, hard X-ray Thomson scattering source |
| format: | conference procceeding |
| conference: | 9th Advanced Accelerator Concepts Workshop |
| year: | 2001 |
| 6 authors: | | | | | | |
| abstract: | An important motivation in the development of the next generation X-ray light sources is to achieve picosecond and sub-ps pulses of hard X-rays for dynamic studies of a variety of physical, chemical anti biological processes. Present hard X-ray sources are either pulse-width or intensity limited, which allows ps-scale temporal resolution only for signal averaging of highly repetitive processes. A much faster and brighter hard X-ray source is being developed at LLNL, based on Thomson scattering of fs-laser pulses by a relativistic electron beam, which will enable X-ray characterization of the transient structure of a sample in a single shot. Experimental and diagnostic techniques relevant to the development of next generation sources including the Linac Coherent Light Source can be tested with the Thomson scattering hard X-ray source. This source will combine an RF photoinjector with a 100 MeV S-band linac. The photoinjector and linac also provide an ideal test-bed for examining space-charge induced emittance growth effects. A program of beam dynamics and diagnostic experiments are planned in parallel with Thomson source development. Our experimental progress and future plans will be discussed. |
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| title: | The FINDER Photoinjector |
| format: | journal article |
| year: | 2007 |
| 6 authors: | | | | | | |
| abstract: | The FINDER photoinjector was developed for the inverse Compton scattering experiment under UCLA- LLNL collaboration. The improvements of this gun from SPARC gun [1, 2] at INFN-LNF (Frascati) and previous UCLA versions of the 1.6 cell S-band photoinjector are detailed here. The gun is designed to have large mode separation to suppress 0 mode excitation which may be a cause of the emittance degradation. In an effort to reduce the RF quadrupole effect the full cell tuners are replaced by vacuum ports. The laser ports are also omitted. Two openings of the solenoid shield are added to top and bottom of it where there were only two openings on the sides. S11 of the cavity was presented. The on-axis electric field was measured by the bead drop method to show the good field balance. The magnetic field in the emittance compensation solenoid was measured and the quadrupole components were derived. |
| keywords: | pbpl |
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| title: | Commissioning of a High-Brightness Photoinjector for Compton Scattering X-Ray Sources |
| format: | journal article |
| year: | 2007 |
| 13 authors: | | | | | | | | | | | | | |
| abstract: | Compton scattering of intense laser pulses with ultra- relativistic electron beams has proven to be an attractive source of high-brightness x-rays with keV to MeV ener- gies. This type of x-ray source requires the electron beam brightness to be comparable with that used in x-ray free- electron lasers and laser and plasma based advanced accel- erators. We describe the development and commissioning of a 1.6 cell RF photoinjector for use in Compton scatter- ing experiments at LLNL. Injector development issues such as RF cavity design, beam dynamics simulations, emit- tance diagnostic development, results of sputtered magne- sium photo-cathode experiments, and UV laser pulse shap- ing are discussed. Initial operation of the photoinjector is described. |
| keywords: | pbpl |
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| title: | Nuclear Photo-Science And Applications with Thomson-Radiated Extreme X-Ray (T-Rex) Sources |
| format: | journal article |
| year: | 2006 |
| 15 authors: | | | | | | | | | | | | | | | |
| abstract: | Recent advances in high brightness rf gun technology, coupled with novel laser systems and architecture have enabled the development of a new class of compact, tunable, monochromatic light sources capable of producing MeV photons with unprecedented brightness. Such new sources rely on Thomson scattering of incident photons produced by a TW-class laser off a bright relativistic electron beam to generate Doppler-upshifted photons in a highly collimated beam. Scaling laws [1] show that a frequency-doubled, 532 nm wavelength, 1 J, 10 ps Fourier transform-limited drive laser pulse interacting with a 250 MeV, 1 nC, 10 ps, 1 mm.mrad normalized emittance, with 0.1% relative energy spread, can yield a 2.24 MeV γ-ray flash with a peak brightness exceeding 1023 photons/[mm2 x mrad2 x s x 0.1% bandwidth]. This number is > 15 orders of magnitude beyond the output of a third-generation synchrotron at the same photon energy. Above ~ 100 keV, the photons can interact with nuclei, and nuclear applications become viable. In this paper, we present a technical overview of T- REX sources and their capabilities, and give a few examples of potential applications of interest. |
| keywords: | pbpl |
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| title: | Experimental characterization of an ultrafast Thomson scattering x-ray source with three-dimensional time and frequency-domain analysis |
| format: | journal article |
| year: | 2004 |
| 18 authors: | | | | | | | | | | | | | | | | | | |
| abstract: | We present a detailed comparison of the measured characteristics of Thomson backscattered xrays produced at the Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures facility at Lawrence Livermore National Laboratory to predicted results from a newly developed, fully three-dimensional time and frequency-domain code. Based on the relativistic differential cross section, this code has the capability to calculate time and space dependent spectra of the x-ray photons produced from linear Thomson scattering for both bandwidth-limited and chirped incident laser pulses. Spectral broadening of the scattered x-ray pulse resulting from the incident laser bandwidth, perpendicular wave vector components in the laser focus, and the transverse and longitudinal phase spaces of the electron beam are included. Electron beam energy, energy spread, and transverse phase space measurements of the electron beam at the interaction point are presented, and the corresponding predicted x-ray characteristics are determined. In addition, time-integrated measurements of the xrays produced from the interaction are presented and shown to agree well with the simulations. |
| keywords: | pbpl |
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| title: | Production of femtosecond pulses and |
| format: | journal article |
| year: | |
| 9 authors: | | | | | | | | | |
| abstract: | |
| keywords: | pbpl |
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| title: | HIgh Energy, High Brightness X-Rays Produced by Compton Back Scattering at the Livermore PLEIADES facility |
| format: | journal article |
| year: | |
| 11 authors: | | | | | | | | | | | |
| abstract: | PLEIADES (Picosecond Laser Electron Interaction for the Dynamic Evaluation of Structures) produces tunable 30-140 keV x-rays with 0.3-5 ps pulse lengths and up to 10^7 photons/pulse by colliding a high brightness electron beam with a high power laser. The electron beam is created by an rf photo-injector system, accelerated by a 120 MeV linac, and focused to 20 μm with novel permanent magnet quadrupoles. To produce Compton back scattered x-rays, the electron bunch is overlapped with a Ti:Sapphire laser that delivers 500 mJ, 100 fs, pulses to the interaction point. K-edge radiography at 115 keV on Uranium has verified the angle correlated energy spectrum inherent in Compton scattering and high-energy tunability of the Livermore source. Current upgrades to the facility will allow laser pumping of targets synchronized to the x-ray source enabling dynamic diffraction and time-resolved studies of high Z materials. Near future plans include extending the radiation energies to >400 keV, allowing for nuclear fluorescence studies of materials. |
| keywords: | pbpl |
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