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J. Cook, D. Helms, W. Skinner

Division (M7), FEL Coordination Group

F. Dylla

IR Demo Project Weekly Report, August 3-7, 1998

August 7, 1998

Management

Highlights for the week include the following:(1) we continued commissioning operations on the recirculation system in preparation for a cw demonstration of energy recovery; and (2) good progress was made in the commissioning of the first three User labs

FEL Installation/Maintenance Activities

The remaining sextupoles were hooked-up and checked out on Monday and Tuesday while we were down for cathode processing. All the magnetic elements are now installed in the FEL. The beam scraper is the only element remaining to be installed in the Beam Transport System and it is ready to be installed on the next maintenance day.

We successfully brazed a sapphire optical cavity mirror with acceptable distortion. will be used for kW operation at 3 microns.

Initial testing of DuPont donated equipment for polymer processing began today.

These mirrors

Mirror cassettes in User Labs 4, 5 and 6 are installed and aligned. optic procurements arrive.

Lab 2 installation will occur as

FEL Commissioning Activities

A good portion of this past week (Friday to Wednesday) was used to resuscitate the cathode for high power operation. We began by reactivating the NEG pumps at 20% higher heating currents followed by several days of HV processing of the gun to remove a persistent field emission source which drew currents as high as 1mA with power supply voltages near 500 kV. The level of current was surprising for internal activity but it was nevertheless accompanied by modest vacuum activity (10e-9 torr) and some x-ray activity. By Tuesday, the gun current had dropped by two