P. Morcombe

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.

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.

Improving power supply performance for the Duke storage ring

As part of the recent Duke storage ring hardware upgrade (2001-2002), a power supply improvement program was put in place to bring all major DC supplies to their specifications. In carrying out this program, power supplies have been modified, tuned, and thoroughly tested. In its actual operation configuration, each power supply was subject to extensive testing to determine its DC stability, reproducibility and linearity, AC ripple and noise, and ramping performance. As a result, all major DC supplies have been improved to meet most important performance specifications for 1 GeV operation.

Duke storage ring tune measurements system using razor blade and photomultiplier

We present in this paper the description of the Duke storage ring tune measurements system. An unusual feature of this system is the use of synchrotron radiation to sense oscillation of the electron beam. This system includes a lens, a razor blade placed at the focus and a photomultiplier. Our experience shows that this system can operate on -70 dBm level and detect electron beam oscillations as small as one micron.

EPICS at Duke University

Since the last Particle Accelerator Conference, the Experimental Physics and Industrial Control System (EPICS) has been utilized for control system development and implementation on several accelerators that have recently been commissioned at the Free Electron Laser Laboratory which is operated under the auspices of the Physics Department at Duke University. The historic Mark III infrared free electron laser formerly located at Stanford University, a recently designed and constructed 280 MeV electron linear accelerator and a 1 GeV storage ring synchrotron are now operating under EPICS control. Commissioning of the new injection linac and the storage ring has gone extremely well. The authors feel that through the employment of a standard controls development environment such as EPICS, considerable amounts of resources, both financial and human, have been saved. The authors note generally positive experiences with EPICS. The highlights of these experiences, as well as some suggestions for future improvements are presented in the body of this report.

Unique features of the OK-4/Duke storage ring XUV FEL and monochromatic /spl gamma/-ray source

The OK-4 is the first storage ring FEL operating in the United States. It was commissioned in November, 1996 and demonstrated lasing in the near UV and visible ranges (345-413 nm) with extracted power of 0.15 W. In addition to lasing, the OK-4/Duke FEL generated a nearly monochromatic (1% FWHM) /spl gamma/-ray beam. In this paper we describe the initial performance of the OK-4/Duke storage ring FEL and /spl gamma/-ray source.

Temperature sensors and controls for the Duke FEL storage ring

This paper describes a prototype system used for sensing and control functions associated with the Duke University 1 GeV electron storage ring. Low cost industrial control systems have been used. The system is capable of handling at least four hundred devices.

Development of a modular and upgradeable fast kicker magnet system for the Duke Storage Ring

A cost effective injection kicker has been developed for the electron storage ring at Duke. Magnet components and driver circuitry are integrated in a modular format that has resulted in a low cost, highly maintainable and upgradeable development system. The driver and magnet can be easily reconfigured from a simple LRC circuit (parallel or series) that provides a pulse approximating a half sinusoid to one utilizing a pulse forming line to provide a more trapezoidal pulse shape. The modular development platform has permitted the kicker to evolve with the storage ring in a way that minimizes further expenditures of time and materials.