First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength

We present the first observation of Self-Amplified Spontaneous Emission (SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, spectral width and intensity fluctuations all corroborate the existing models for SASE FELs.Comment: 6 pages including 6 figures; e-mail: [email protected]

Dynamic in situ bakeout for the HERA proton ring vacuum system

Due to the restricted space for the heaters and insulation in the normal conducting magnets of the HERA proton ring, the bakeout process must be done very carefully in order to prevent damage of the magnets. A special high temperature thermal insulating material allows bakeout of the stainless steel vacuum chambers by a heating jacket as thin as 3.5 mm. When built into a normal conducting accelerator magnet, a bakeout temperature of 300°C is achieved without overheating the surrounding magnet. After more than 24 h the maximum temperature of 68°C reached at the sensitive coil of the magnet is well below the 80°C critical temperature of the epoxy. With the described bakeout system no heat sink is necessary to protect the magnet's components from the high temperatures. Control and regulation of the temperature of the vacuum chambers are done by means of thermocouple probes, attached to the outer surface of the chambers near the coaxial heating elements