Management

The FEL photogun was successfully brought back on line early in the month of November and recommissioning of the recirculation loop commenced. By month's end cw lasing with more than 50 watts was achieved with a recirculation current of 0.55 mA.

The Jefferson Lab FEL group co-organized a workshop on FEL applications that was held at SURA headquarters on Nov. 20. Other organizers included the FEL teams at Duke, Vanderbilt and BNL.

CA 321: Upgrade Cryomodule System

The four cavity pair assemblies have been completed. Testing of the first cavity pair is on hold due to a cryogenic system breakdown in the Vertical Test Area. Testing is scheduled to resume the first week of December.

CA 521: FEL COMMISSIONING

On 11 Nov 98 we finally succeeded in bringing up a working photocathode gun. The remainder of the month was spent doing intensive commissioning of the recirculation loop. First, however, within 30 hours of turn-on after being down nearly three months, we had completely recovered the full performance of the straight-ahead machine. By month's end we had achieved cw lasing at 40 W with 0.55 mA of recirculated current and with the gun operated at 18.7 MHz. These laser powers were measured in the optical control room; the power levels emitted at the laser areapproximately 1.4 times larger. At month's end we were reconstituting the gun. (Note: By 15 Dec 98, we had achieved cw lasing at 211 W upstairs (which equates to 300 watts output at the laser)with 1.5 mA of recirculated current and with the gun operated at 37.4 MHz.)

FEL INSTALLATION

By month's end the photocathode scanner was almost fully complete, and it was being used during the aforementioned reconstitution of the gun. Minor installation/maintenance tasks were done early in the month; the principal focus at that time was getting the gun working. Once that was achieved, the remainder of the month was focused exclusively on commissioning the machine.