I.V. Pinayev

Lasing in visible and ultraviolet regions in an optical klystron installed on the VEPP-3 storage ring

Abstract Lasing in a wide 2400–6900 A spectral range (from visible to ultraviolet) was reached in the optical klystron OK-4 installed on the VEPP-3 storage ring. OK-4 is the first FEL operating in UV.

A free electron laser-photoemission electron microscope system (FEL-PEEM)

We report first results from our effort to couple a high resolution photoemission electron microscope (PEEM) to the OK-4 ultraviolet free electron laser at Duke University (OK-4/Duke UV FEL). The OK-4/Duke UV FEL is a high intensity source of tunable monochromatic photons in the 3–10 eV energy range. This tunability is unique and allows us to operate near the photoemission threshold of any samples and thus maximize sample contrast while keeping chromatic berrations in the PEEM minimal. We have recorded first images from a variety of samples using spontaneous radiation from the OK-4/ Duke UV FEL in the photon energy range of 4.0–6.5 eV. Due to different photothreshold emission from different sample areas, emission from these areas could be turned on (or off) selectively. We have also observed relative intensity reversal with changes in photon energy which are interpreted as density-of-state contrast. Usable image quality has been achieved, even though the output power of the FEL in spontaneous emission mode was several orders of magnitude lower than the anticipated full laser power. The PEEM has achieved a spatial resolution of 12 nm.

Giant high-peak power pulses in the UV OK-4/Duke storage ring FEL using the gain modulator ☆

Abstract We use the gain modulation technique to generate giant pulses in the OK-4/Duke storage ring FEL for applications requiring high peak power. This technique provides the increase of the peak power by several orders of magnitude. It is also very reliable, predictable and reproducible. The design, the parameters and the gain modulator performance are described. Comparison of expected and measured pulse forms is presented. Application of gain modulator for future harmonic generation experiments is also discussed.

Lasing in visible and ultraviolet regions in an optical klystron installed on the VEPP‐3 storage ring (invited)

Since 1979, experiments on the storage ring VEPP‐3 with an optical klystron (OK) have been performed at the INP Academy of Sciences of the USSR. In 1979, 1981, and 1983, three different OK magnetic systems based on SmCo permanent magnets undulators were installed at the VEPP‐3 straight section at 6300‐A wavelength. The following gains per pass have been obtained: 0.5% in 1980, 1% in 1982, and 2%–2.5% in 1984. In late 1985, we decided to improve the storage ring VEPP‐3 and develop a dc bypass, a special straight section dedicated for OK operation. The bypass allowed us to install an OK magnetic system of 7.8 m length and significantly increase the gain per pass in March of 1988. The bypass was installed at the storage ring VEPP‐3 on 3 June 1988. We obtained lasing in the red and yellow light spectral range from 5800 to 6900 A with 5%–10% gain per pass. After changing mirrors for new ones with minimum losses at 4150 A, lasing in the violet and near UV spectral range with 3%–6% gain per pass from 4500 to 375...

Project of a race-track microtron-recuperator for a free electron laser

Abstract A project for a race-track microtron — the beam source for a FEL — is considered. The beam, utilized in a FEL, returns to a microtron where it decelerates and releases its energy to an rf system. The energy of electrons is 35 MeV and the mean current ranges up to 0.1 A.

First UV/visible lasing with the OK-4/Duke storage-ring FEL: design and initial performance

The OK-4/Duke storage ring FEL was commissioned in November 1996 and demonstrated lasing in the near UV and visible ranges (345 - 413 nm). The OK-4 is the first storage ring FEL with the shortest wavelength and highest power for UV FELs operating in the United States. During one month of operation we have performed preliminary measurements of the main parameters of the OK-4 FEL: its gain, lasing power and temporal structure. In addition to lasing, the OK-4/Duke FEL generated a nearly monochromatic (1% FWHM) 12.2 MeV gamma-ray beam. In this paper we describe the design and initial performance of the OK-4/Duke storage ring FEL. We compare our predictions with lasing results. Our attempt to lase in the deep UV range (around 193 nm) is discussed. The OK-4 diagnostic systems and performance of its optical cavity are briefly described.

Status of the booster synchrotron for Duke FEL storage ring

In this paper we present current status of the Booster Synchrotron for the Duke FEL storage ring. The Booster which is recently under design, fabrication and construction, will provide full energy injection into the storage ring at energy from 0.3 to 1.2 GeV. The Duke storage ring FEL (SR FEL) operates in lasing mode with 193-700 nm wavelength range. The geometry of the Duke SR FEL provides for interacting head-on collision of e-beam and FEL photons. This mode of operation is used to generate intense beams of /spl gamma/-rays from 2 MeV to about 200 MeV (currently from 2 MeV to 58 MeV). Generation of /spl gamma/-rays with energy exceeding 20 MeV causes the loss of electrons, which will be replaced by injection from the Booster operating in a top-off mode. The paper presents design and status for elements of magnetic system and vacuum system, as well as design and parameters of fast extraction kicker with 11 nS pulse duration. All these element are designed and will be fabricated by Budker Institute of Nuclear Physics, Novosibirsk, Russia.

System for the control and stabilizing of OK-4/Duke FEL optical cavity

The control system of an optical cavity is described. Usage of the piezoelectric actuators and position sensitive photodetectors in this system allows us to reach a resolution at a submicroradian level and to suppress mirror vibrations below 50 Hz.

DUKE FEL STORAGE RING LIGHT SOURCES AND APPLICATIONS

Abstract In this paper we present the status of the Duke UV FEL (Free Electron Laser) storage ring, ring based light sources, and a related multi-disciplinary application program. Using the OK-4 optical klystron system, we have demonstrated tunable spontaneous radiation from the near Infrared (IR) to UV, coherent laser radiation from 345 to 413 nm, and Compton back-scattered linearly polarized γ-ray radiation from 3 to 16 MeV. We report the progress made in developing new light source capabilities. We also report user interface development for a pilot application program organized to utilize various ring driven sources. We discuss future upgrades and additions to the ring based sources.

Status of the Novosibirsk high-power free-electron laser project

The first stage of Novosibirsk high power free electron laser (FEL) was commissioned in 2003. It is based on normal conducting CW energy recovery linac. Now the FEL provides electromagnetic radiation in the wavelength range 120-180 micron. The average power is 100 W. The measured linewidth is 0.3%, which is close to the Fourier-transform limit. The assembly of user beamline is in progress. Plans of future developments are discussed.