Proposed UV-FEL user facility at BNL

Nuclear Instruments and Methods in Physics Research Section A:

Yang

1992

Self Cite

The 'Fresh Bunch' technique is being proposed as a method of increasing the gain and power of FEL amplifiers in which the length of the optical radiation pulse is shorter than the length of the electron bunch. In a multi-stage FEL, electron beam energy spread is increased by the FEL interaction in the early stages. In the 'Fresh Bunch' technique, the low energy spread of the electron beam is recovered by shifting the radiation pulse to an undisturbed part of the electron bunch, thus improving the gain and trapping fraction in later stages. A test case for the application of the Fresh Bunch method is demonstrated by numerical simulation. In this particular example we examine a subharmonically seeded VUV Free-Electron Laser. We begin with the generation of harmonic radiation, which takes piace over one part of the electron bunch. Then the radiation is shifted by means of a strong dispersive section to a fresh part of the bunch for exponential amplification and tapered wiggler amplification. By starting over with a new ensemble of electrons, the energy spread introduced by the bunching in the fundamental is removed, leading to an increased gain. Furthermore, it is possible to use a much stronger seed in the fundamental without incurring the penalty of a large energy spread later on. We note that more than a single application of the 'Fresh Bunch' method may be done in a single FEL multiplieramplifier. Thus x-ray wavelengths may be reached by successive multiplication in a chain of FEL amplifiers starting from a tunable seed laser. "This work is performed under the auspices of the U.S. Department of Energy under contract number crm0o16.

Section: The Model Felmentioning

confidence: 99%

Section: Oooamentioning

confidence: 99%

See 1 more Smart Citation

The “fresh-bunch” technique in FELS

Nuclear Instruments and Methods in Physics Research Section A:

Yang

1992

Self Cite

“…Let us use the parameters of the wiggler and beam ofthe proposed BNL UV FEL User's Facility 3. Let us use the parameters of the wiggler and beam ofthe proposed BNL UV FEL User's Facility 3.…”

mentioning

confidence: 99%

<title>High-precision beam alignment of electromagnet wigglers</title>

Electron-Beam Sources of High-Brightness Radiation

Qiu

1993

The performance of Free-Electron Lasers depends critically on the quality of the alignment of the electron beam to the wiggler's magnetic axis and the deviation ofthis axis from a straight line. The measurement of the electron beam position requires numerous beam position monitors in the wiggler, where space is at premium. The beam position measurement is used to set beam steerers for an orbit correction in the wiggler. We propose an alternative high precision alignment method in which one or two external Beam Position Monitors (BPM) are used. In this technique, the field in the electro-wiggler is modulated section by section and the beam position movement at the external BPM is detected in synchronism with the modulation. A beam offset at the modulated beam section will produce a modulation of the beam position at the detector that is a function of *

“…(ii) advancement of FEL technology to produce ultraviolet radiation [1], [2], [3], and (iii) exploration of the short-wavelength limits for high-brightness electron guns.…”

Section: Introductionmentioning

confidence: 99%

Status of the visible free-electron laser at the Brookhaven accelerator test facility

Batchelor

Nuclear Instruments and Methods in Physics Research Section A:

Fernow

et al. 1992

Self Cite

The 500 nm Free-Electron Laser(FEL) at the Accelerator Test Facility (ATF) of the BrookhavenNational Laboratory isreviewed. We present an overview ofthe ATF, a highbrightness, 50-MEV, electron accelerator and laser complex which is a users' facility for DISCLAIMERThis report was prepared as an account of work sponsored by an agency of the United Stat¢s Government. Neither the United State, s Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Refercnc¢ heroin to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise dots not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.