B. Burnham

Giant laser pulses in the Duke storage ring UV FEL

Abstract We have studied the dynamics of giant pulse generation in the Duke UV FEL with peak power of several gigawatts. The giant pulses will be provided by a FEL gain modulation technique developed for the OK-4 UV FEL at Novosibirsk, Russia. A new mechanism for “super-pulse” generation was discovered during these studies. It allows the generation of peak power up to 10 GW using the “phase space” refreshment of the electron beam caused by synchrotron motion [V. Litvinenko et al., to be published]. We have developed a new macro-particle code for giant pulse simulation including all known mechanisms of storage ring FEL interaction. Results of these giant pulse simulations are presented in the paper.

Duke storage ring UV/VUV FEL: status and prospects

Abstract A 1.1 GeV electron storage ring dedicated for UV-VUV FEL operation was commissioned last year at the Duke University Free Electron Laser Laboratory [V.N. Litvinenko et al., Commissioning of the Duke storage ring, Proc. 1995 Particle Accelerator Conf., Dallas, TX, May 1–5, 1995]. The XUV FEL project, based on the collaboration of the Duke FEL Laboratory and Budker Institute for Nuclear Physics (Novosibirsk, Russia) is described. The OK-4 UV FEL has arrived from Novosibirsk at the Duke FEL laboratory and is in the process of installation. The main parameters of the Duke Free Electron Laser Laboratory (DFELL) storage ring, the OK-4 optical klystron, and the experimental set-up are presented. The parameters of the UV-VUV FEL are given and possible future upgrades to this system are discussed. We have developed a new macro-particle code for storage ring simulation including all known mechanisms of storage ring FEL interaction. We confirm our expectations on the average and peak power for the OK-4. In addition we have studied a giant pulse mode of operation. A new mechanism of “super-pulse” generation was discovered during these studies. It allows the generation of peak power up to 10 GW using “phase-space” refreshment of the electron beam caused by synchrotron motion [V.N. Litvinenko, B. Burnham, J.M.J. Madey and Y. Wu, Nucl. Instr. and Meth. A 358 (1995) 334].

Commissioning of the Duke Storage Ring

The commissioning of the 1 GeV Duke Storage Ring began in November, 1994 with the demonstration of injection, storage and ramping to 1 GeV at the first attempt. The ring is now operational. The Duke project is unique in that the storage ring and linac were designed, constructed and commissioned by a small new University laboratory, operating on a low budget. The team is comprised of six accelerator physicists and graduate students, eight engineers, and fifteen technicians.

Dynamics of the Duke storage ring UV FEL

Abstract The Duke 1 GeV storage ring will be commissioned this year with a 280 MeV linac-injector. We intend to ramp the energy to 0.7–1.0 GeV for FEL operation. The OK-4 optical klystron will be shipped from the Budker Institute of Nuclear Physics to Duke in early 1995. The OK-4 will be the first FEL to operate on the Duke storage ring. This paper is dedicated to the study of the OK-4 performance in the CW mode of operation in the UV range, using a 3-D code developed by the authors.

The performance of the Duke FEL storage ring

Abstract Commissioning of the Duke FEL storage ring has been completed successfully. During commissioning and initial operation, a series of performance measurements were performed on the storage ring. In this paper we discuss the techniques used in the measurements, present the measurements results, and compare the measured parameters with the design specifications.

The Duke storage ring control system

The Duke storage ring is a dedicated facility for the UV-VUV FEL operation. The low level computer control system for the Duke storage ring is developed using EPICS. The control hardware employs several different architectures including CAMAC, GPIB, Allen Bradley, and VME. The high level control is implemented in Tcl-Tk scripts running on SPARCstations. Tcl-Tk provides the global control capabilities such as the energy ramping, the orbit compensation, and the tune and chromaticity control. The Duke storage ring control system was tested and operational for storage ring commissioning in Nov. 1994. During commissioning, additional control tools were developed to facilitate the operation.

Performance of achromatic lattice with combined function sextupoles at Duke Storage Ring

The 1 GeV Duke Storage Ring was very successfully commissioned with performance exceeding initial specifications. In this paper we present design and performance data of its unique achromatic lattice with combined function magnets in the ring arcs.

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.

mm-wave isochronous FEL and hard X-ray inverse Compton source at the Duke storage ring

Abstract We propose to operate an isochronous mm-wave FEL at the Duke storage ring. Resonant FEL conditions for mm-waves will be provided by the off-axis interaction with an electromagnetic wave. A special optical resonator with holes for the e-beam is proposed for pumping a hard X-ray inverse Compton source with very high brightness. Simulation results for proposed mm-wave FEL operation on the Duke storage ring are discussed in a separate article in these proceedings. The expected performance of the hard X-ray inverse Compton source is presented.

Specific features of magnet design for the Duke FEL storage ring

The 1 GeV Duke FEL storage ring is dedicated to drive UV and VUV free electron laser devices. The high brightness and low emittance electron beams needed for these devices demand high performance and tight tolerances on the storage ring magnet lattice. Tight tolerances include close spacing of magnetic elements. We show how combined function magnets are used to eliminate discrete elements and odd shaped end pieces which cause magnetic coupling, saturation and severe undesirable field nonlinearities. Using this scheme we are able to achieve desirable ring dynamic aperture with only minor modification of existing hardware. Also included is a discussion of a non-standard septum magnet with stray field compensation which will be employed by this storage ring. The design, testing procedures, and preliminary results are outlined for this magnet.<<ETX>>