Management

The month was spent diagnosing problems with the photogun. Shortly after the month's end (Nov. 4), the gun was successfully brought back on-line after replacing the cesiator and a series of high voltage conditioning runs. FEL commissioning activities re-commenced on the same date.

CA 321: Upgrade Cryomodule System

Pair Assembly

In preparation for assembly of the four pairs the following activities were accomplished during October:

• The cleanroom was brought back on line and qualified after a complete upgrade of the Class 100 assembly area.
• A teststand was cleaned and baked to accept assembled pairs.
• All eight cavities were dimensionally inspected .
• All eight cavities were RF tuned and FPC Qext and field probes calibrated
• End dish and inner adapters were fabricated for the first two pairs
• The pair IA074/ IA076 was assembled and procedures established. The pair ended up with a leak on the indium seal at the dogleg window/FPC flange area due to miss alignment of the indium seal.
• IA074/IA076 was disassembled, reassembled, leak checked and inserted into the vertical test stand and moved to the dewar.

Cryounit Assembly will begin when the first fully qualified cavity pair assembly is turned over.

CA 521: FEL COMMISSIONING

The month of October was spent on a frustrating program of resurrecting the photocathode gun. All the details can be found in the month's weekly reports. As of 31 Oct. we had not succeeded; however, as of this writing (13 Nov. 98) we have a working gun and an FEL that is working as well as it ever did.

Other commissioning highlights include making considerable progress toward modeling the full machine with PARMELA, developing preliminary plans for beam-breakup experiments with the accelerator driver, and starting the process of developing the conceptual design of the FEL upgrade.

FEL INSTALLATION

Highlights for October include carefully auditing the Machine Protection System, recertifying the Personnel Protection System, developing a scanner for mapping the quantum efficiency of the cathode, vacuum-testing the Thomson backscattering X-ray detection chamber that will eventually be installed near the wiggler, and improving the alignment of the wiggler and nearby quadrupole magnets.