Management

This week was a maintenance week for the FEL. The items that were accomplished are listed below. A significant event was receipt of the high power (kilowatt class) optics for 3 micron operation. Our plan is to install these optics next week so that they are in-place for the re-start of operations during the week of April 12th.

On Wednesday two Congressional staff members visited the FEL for a tour and briefing, Grayson Winterling from Senator Warner's office and Steve Stombres from Congressman Bateman's office.

The following 12 papers related to the FEL were presented at this week's Particle Accelerator Conference in New York:

"Development of a 50 kW CW L-Band Rectangular Window for Jefferson Lab FEL Cryomodule" Authors: Nguyen, Phillips, Preble

"Physics of JLab FEL Injector" Author: Yunn

"Performance of the Electron Beam Diagnostics at Jefferson Lab's High Power Free Electron Laser", Authors: P. Piot, G. A. Krafft, K. Jordan, A. Grippo, J. Song

"A High Thermal Conductivity Waveguide Window for use in a Free Electron Laser"

Authors: T. Schultheiss, V. Christina, M. Cole, J. Rathke, T. Elliott, V. Nguyen, L. Phillips, J. Preble

"Magnetic Measurement of the PI Bend Dipole Magnets for the IR-FEL at the Thomas Jefferson National Accelerator Facility" Authors: Tremblay, Biallas, Douglas, Karn

"Making Dipoles to Spectrometer Quality Using Adjustments During Measurement" Authors: Biallas, Bullard, Douglas, Guerra, Harwood, Hiatt, Karn, Menefee, Sullivan, Tremblay, Wolfley, also from Northrop-Grumman: Christina, Schultheiss, Tepes

"High Average Power Free-Electron Lasers" Author: Benson

"Performance of the Accelerator Driver of Jefferson Laboratory's Free-Electron Laser" Authors: Bohn, Biallas, Douglas, Evans, Fugitt, Hill, Jordan, Krafft, Li, Merminga, Neil, Piot, Preble, Shinn, Siggins, Walker, Yunn

"Results of a Self-Consistent Simulation of the CSR Effect on Emittance Growth" Author: Li

"The Impact of Coherent Synchrotron Radiation on the Beam Transport of Short Bunches" Author: Li

"Beam Current Limitations in the Jefferson Lab FEL: Simulations and analysis of proposed Beam Break-up Experiments" Authors: Campisi, Douglas, Hovater, Krafft, Merminga, Yunn

"First Results on Energy Recovery in the Jefferson Lab IRFEL" Authors:

Merminga, Benson, Biallas, Bohn, Douglas, Dylla, Evans, Fugitt, Hill, Jordan, Krafft, Li, Neil, Oepts, Piot, Preble, Shinn, Siggins, Walker, Yunn

Installation/Maintenance Activities

The following is a list of FEL maintenance activities that were completed this week:

The Gun's photocathode was replaced, passed preliminary testing, and the entire Gun is in the middle of a bake cycle that will be completed this weekend or early next week.

Two (2) new sapphire mirrors for the FEL Optical Cavity were received and mounted in their holders. Preliminary tests indicate the mirrors will be excellent for lasing at high power at 3.0 µm. They will be installed next week.

The foils for 3 viewers (1G01, 2G00, and 4F09) were replaced with 5.0 µm foil and vacuum lines pumped back down. The thicker 5.0 µm foils have a smoother surface than the standard 1.5 µm foils and thus improved specular reflectance. This will allow improved emmittance measurements.

The optics was aligned for the 3F02 viewer. This viewer is for machine diagnostics.

Cables for the Optical Power detector were run upstairs to get the electronics out of the radiation fields in the vault.

All of the BLM's were included in the MPS Master Reset signal.

The FEL optics group provided support for the Physics Division to set up a far-infrared laser system in User Lab 6. This laser system will eventually be installed in the tunnel to very accurately measure the CEBAF beam energy.

The autocorrelator stepper motor's hardware controller was moved from its proprietary controller to a standard controller. Modifications to the low-level driver progress.

Work on the optical transport system and the LSS for User Lab 3 progresses, we can now control and readback the state of the mirror cassette.