11 papers
| title: | Properties of the ultrashort gain length, self-amplified spontaneous emission free-electron laser in the linear regime and saturation |
| format: | journal article |
| year: | 2003 |
| 26 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | VISA (Visible to Infrared SASE Amplifier) is a high-gain self-amplified spontaneous emission (SASE) free-electron laser (FEL), which achieved saturation at 840 nm within a single-pass 4-m undulator. The experiment was performed at the Accelerator Test Facility at BNL, using a high brightness 70-MeV electron beam. A gain length shorter than 18 cm has been obtained, yielding a total gain of 2x10(8) at saturation. The FEL performance, including the spectral, angular, and statistical properties of SASE radiation, has been characterized for different electron beam conditions. Results are compared to the three-dimensional SASE FEL theory and start-to-end numerical simulations of the entire injector, transport, and FEL systems. An agreement between simulations and experimental results has been obtained at an unprecedented level of detail. |
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| title: | Results of the VISA SASE FEL Experiment at 840 nm |
| format: | conference procceeding |
| conference: | 24th International Free Electron Laser Conference |
| year: | 2003 |
| 26 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | VISA (Visible to Infrared SASE Amplifier) is a high-gain self-amplified spontaneous emission (SASE) free-electron laser (FEL), which achieved saturation at 840 nm within a single-pass 4-m undulator. A gain length shorter than 18 cm has been obtained, yielding the gain of 2x10(8) at saturation. The FEL performance, including the spectral, angular, and statistical properties of SASE radiation, has been characterized for different electron beam conditions. The results are compared to 3-D SASE FEL theory and start-to-end numerical simulations of the entire injector, transport, and FEL system. Detailed agreement between simulations and experimental results is obtained over the wide range of the electron beam parameters. |
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| title: | Properties of an Ultra-Short Gain Length, Saturated, Self-Amplified Spontaneous Emission FEL |
| format: | preprint |
| year: | 2002 |
| 26 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The VISA experiment, conducted at the BNL Accelerator Test Facility (ATF), has studied the properties of SASE FEL process in a saturating system. The experiment utilized a high brightness electron beam and a strong focusing undulator. Saturated gain greater than 108, with a power gain length below 18 cm, was obtained at 840 nm. Measurements of FEL gain, spectral and angular properties of SASE radiation are reported, and the results are compared to theory and to start-to-end simulations of the system. FEL performance was found critically dependent on the compression of the electron beam. |
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| title: | Characterization of an 800 nm SASE FEL at saturation |
| format: | conference procceeding |
| conference: | 23rd International Free Electron Laser Conference |
| year: | 2002 |
| 24 authors: | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | Visible to Infrared SASE Amplifier is a free electron laser (FEL) designed to saturate at a radiation wavelength of 800 nm within a 4 m long, strong focusing undulator. A large gain is achieved by driving the FEL with 72 MeV, high brightness beam of BNL's accelerator test facility. We present measurements that demonstrate saturation in addition to the frequency spectrum of the FEL radiation. Energy, gain length and spectral characteristics are compared and shown to agree with simulation and theoretical predictions. (16 References). |
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| title: | Visible-infrared self-amplified spontaneous emission amplifier free electron laser undulator |
| format: | unknown |
| year: | 2001 |
| 17 authors: | | | | | | | | | | | | | | | | | |
| abstract: | The visible-infrared self-amplified spontaneous emission amplifier (VISA) free electron laser (FEL) is an experimental device designed to show self-amplified spontaneous emission (SASE) to saturation in the near infrared to visible light energy range. It generates a resonant wavelength output from 800?600 nm, so that silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is designed to show how SASE FEL theory corresponds with experiment in this wavelength range, using an electron beam with emittance close to that planned for the future Linear Coherent Light Source at SLAC. VISA comprises a 4 m pure permanent magnet undulator with four 99 cm segments, each of 55 periods, 18 mm long. The undulator has distributed focusing built into it, to reduce the average beta function of the 70?85 MeV electron beam to about 30 cm. There are four FODO cells per segment. The permanent magnet focusing lattice consists of blocks mounted on either side of the electron beam, in the undulator gap. The most important undulator error parameter for a free electron laser is the trajectory walk-off, or lack of overlap of the photon and electron beams. Using pulsed wire magnet measurements and magnet shimming, we were able to control trajectory walk-off to less than |
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| title: | Measuring FEL radiation properties at VISA-FEL |
| format: | conference procceeding |
| conference: | 2001 Particle Accelerator Conference |
| year: | 2001 |
| 25 authors: | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The VISA (Visible to Infrared SASE Amplifier) SASE free electron laser has been successfully operated at the Accelerator Test Facility (ATF) at BNL. High gain and saturation were observed at 840 nm. We describe here the diagnostic system, experimental procedures and data reduction algorithms, as the FEL performance was measured along the length of the undulator. We also discuss selected spectral radiation measurements. (10 References). |
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| title: | Initial gain measurements of an 800 nm SASE FEL, VISA |
| format: | conference procceeding |
| conference: | 22nd International Free Electron Laser Conference |
| year: | 2001 |
| 26 authors: | | | | | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | The visible to infrared SASE amplifier (VISA) FEL is designed to obtain high gain at a radiation wavelength of 800 nm. The FEL uses the high brightness electron beam of the accelerator test facility (ATF), with energy of 72 MeV. VISA uses a novel, 4 m long, strong focusing undulator with a gap of 6 mm and a period of 1.8 cm. To obtain large gain the beam and undulator axis have to be aligned to better than 5 mu m. Results from initial measurements on the alignment, gain, and spectrum will be presented and compared to theoretical calculations and simulations. (10 References). |
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| title: | Status and initial commissioning of a high gain 800 nm SASE FEL |
| format: | conference procceeding |
| conference: | 21st International Free Electron Laser Conference |
| year: | 2000 |
| 22 authors: | | | | | | | | | | | | | | | | | | | | | | |
| abstract: | We describe the status and initial commissioning of the visible to infrared SASE amplifier (VISA) experiment. VISA uses a strong focusing 4 m undulator, the Brookhaven National Laboratory ATF linac with an energy of 72 MeV, and a photoinjector electron source. The VISA fundamental radiation wavelength is near 800 nm and the power expected at saturation is near 60 MW. Power, angular and spectral measurements are planned for the VISA radiation and these results will be analyzed and compared with SASE FEL theory and computer simulation. In addition, the induced electron beam micro-bunching will be measured using coherent transition radiation. (12 References). |
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| title: | The VISA FEL Undulator |
| format: | conference procceeding |
| conference: | 20th International Free Electron Laser Conference |
| year: | 1999 |
| 14 authors: | | | | | | | | | | | | | | |
| abstract: | The Visible-Infrared SASE Amplifier (VISA) FEL is an experimental device designed to show self amplified spontaneous emission (SASE) to saturation in the 800-600 nm range, where silicon detectors may be used to characterize the optical properties of the FEL radiation. VISA is the first SASE FEL designed to saturate, and its diagnostics will provide important checks of theory. |
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| title: | Measurements of gain larger than 10(5) at 12 mu m in a self-amplified spontaneous-emission free-electron laser |
| format: | unknown |
| year: | 1998 |
| 14 authors: | | | | | | | | | | | | | | |
| abstract: | We report measurements of very large output intensities corresponding to a gain larger than 10/sup 5/ for a single pass free-electron laser operating in the self-amplified spontaneous emission (SASE) mode at 12 mu m. We also report the observation and analysis of intensity fluctuations of the SASE radiation intensity in the high-gain regime. The results are compared with theoretical predictions and simulations. (18 References). |
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| title: | UCLA-KIAE focusing permanent magnet undulator for SASE experiment |
| format: | conference procceeding |
| conference: | 19th International Free Electron Laser Conference |
| year: | 1998 |
| 9 authors: | | | | | | | | | |
| abstract: | A description of a new 2 m undulator is presented which was specially designed and manufactured for a SASE mode FEL experiment. It is a one section two plane focusing permanent magnet construction. The uniform period length is 2.06 cm, total number of periods is 98. The peak field on the axis is 5.4 kG for a 5 mm gap. (8 References). |
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