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The Duke storage ring is a facility dedicated for the deep UV free
electron laser (FEL) development. It is especially designed for high
peak power applications, having a long optical cavity and large energy
acceptance. In this paper we describe a FEL gain modulator and optical
cavity control system, which are essential for obtaining maximal peak
po...
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... used for support of the mirror mounts are placed on the regular floor and, therefore, are prone to ambient vibrations. The tests showed that even changing of a static load on the optical table or to the floor nearby causes unacceptable changes of the mirror position. That is why an active feedback system for stabilizing mirrors, shown in the Fig. 1 was implemented. For this purpose two posts were installed inside the ring room, and reference semiconductor lasers and position sensitive detectors were mounted on the posts. The auxiliary concave mirror firmly attached to the optical cavity mirror mount reflects laser light. Tilt angle of the cavity mirror is measured by a position ...
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Citations
... At the middle of December, 1996 the operations of the Duke storage ring has been stopped and next operations of the OK-4 FEL was possible only in 1998. In April, 1998 we demonstrated lasing in the deep-UV range with tunability from 226 nm to 256 nm and also tested the operation of newly build gain modulator [7]. After three months shut-down for construction of initial stage of new Keck Life Science building , we reestablished operation of the OK-4 FEL and lased at shorter wavelength down to 217 nm. ...
... Most of the technical parameters of the storage ring and the OK- 4 FEL has been presented in our previous publications [10, 8]. The recent developments of the OK-4/Duke storage ring FEL involved installation and commissioning closed orbit measuring system comprised of 34 units of Bergoz BPM electronics [11], the new timing system, the gain modulator [7]. We have also purchased the Hamamatsu streak camera with 2 ps resolution which is used for both storage ring and the OK-4 FEL diagnostics. ...
... We out-coupled maximum of 100 mW of average laser power per mirror into TEMoo mode using 700 MeV electron beam with 16 mA average current in two bunches. Giant pulses with 50-200 microsecond duration were generated using the gain modulator [7], at a maximum reprate of 30 Hz with maximum 0.25-0.4 mJ per macropulse and a peak out-coupled power of about 0.3 MW. ...
In this paper we present the result of the deep-UV lasing with the
OK-4/Duke storage ring FEL. The OK-4 FEL was initially commissioned in
the near-UV at Duke Free Electron Laboratory in November, 1996 followed
by a year-long shutdown. After re-establishing the storage ring
operation in early 1998, the OK-4 FEL lasing was demonstrated in the
wavelength range of 217 to 256 nm in 1998. A number of lasing modes with
electron energies ranging from 300 to 750 MeV have been established to
accommodate application research. Starting September, 1998, the coherent
deep-UV radiation is used for applications in cornea surgery, cell
biology, surface physics, and nuclear physics. In this paper we report
the results of the deep-UV lasing with the OK-4/Duke storage ring FEL as
well as our plans to advance towards the VUV
... At the middle of December, 1996 the operations of the Duke storage ring has been stopped and next operations of the OK-4 FEL was possible only in 1998. In April, 1998 we demonstrated lasing in the deep-UV range with tunability from 226 nm to 256 nm and also tested the operation of newly build gain modulator [7]. After three months shut-down for construction of initial stage of new Keck Life Science building , we reestablished operation of the OK-4 FEL and lased at shorter wavelength down to 217 nm. ...
... Most of the technical parameters of the storage ring and the OK-4 FEL has been presented in our previous publications [10,8]. The recent developments of the OK-4/Duke storage ring FEL involved installation and commissioning closed orbit measuring system comprised of 34 units of Bergoz BPM electronics [11], the new timing system, the gain modulator [7]. We have also purchased the Hamamatsu streak camera with 2 ps resolution which is used for both storage ring and the OK-4 FEL diagnostics. ...
... We out-coupled maximum of 100 mW of average laser power per mirror into TEMoo mode using 700 MeV electron beam with 16 mA average current in two bunches. Giant pulses with 50-200 microsecond duration were generated using the gain modulator [7], at a maximum reprate of 30 Hz with maximum 0.25-0.4 mJ per macropulse and a peak out-coupled power of about 0.3 MW. ...
In this paper we present the result of the deep-UV lasing with the OK-4/Duke storage ring FEL. The OK-4 FEL was initially commissioned in the near-UV at Duke Free Electron Laboratory in November, 1996 followed by a year-long shutdown. After re-establishing the storage ring operation in early 1998, the OK-4 FEL lasing was demonstrated in the wavelength range of 217 to 256 nm in 1998. A number of lasing modes with electron energies ranging from 300 to 750 MeV have been established to accommodate application research. Starting September, 1998, the coherent deep-UV radiation is used for applications in cornea surgery, cell biology, surface physics, and nuclear physics. In this paper we report the results of the deep-UV lasing with the OK-4/Duke storage ring FEL as well as our plans to advance towards the VUV
In this paper, we describe optical feedback system of VUV Regenerative FEL Amplifier (RAFEL) at the TESLA test facility at DESY. The aim of the RAFEL experiment is to construct fully coherent, tunable VUV radiation source by means of applying narrow-band optical feedback in the VUV SASE FEL operating currently at DESY. One of the problem of the realization of the RAFEL is severe requirements for the angular stability of the optical elements (about few microradians). This problem has been solved by means of installation of active alignment system with reference laser. Another problem is alignment of optical elements separated by within complicated experimental conditions connected with aperture limitations (down to . This problem has been solved in two steps. Preliminary alignment with an accuracy of about has been performed with laser alignment system and OTR screens used at the TTF accelerator for electron beam diagnostics. Final alignment has been performed with VUV SASE FEL radiation. Measured feedback coefficient is about 1 percent and is in agreement with the designed value.
In this paper, we report measured parameters of the OK-4 FEL driven by the Duke storage ring. The OK-4 FEL was being operated continuously for 2 yr in the broad wavelength range for user applications utilising spontaneous and coherent XUV and UV radiation as well as Compton back-scattered γ-rays in the range of 2–58 MeV. During this time, the OK-4 FEL lased in the range from 193.7 to about 730 nm using five sets of mirrors and electron beam energies from 240 to 800 MeV. Our predictions for the OK-4 FEL are compared with measured performance, both in the CW and in the giant pulse mode. We discuss our future plans for the OK-4 FEL operation as well as the construction and commissioning of the OK-5 FEL with helical wigglers.
