Minutes of A0 photoinjector group meeting Monday August 30th, 2004 minutes at: http://home.fnal.gov/~piot/FridayMeeting/Minutes/ * Next meeting: Monday September 13th 10:30 CDT, in WH10 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!! A0 will be shutdown during the week of September 6th [NO LCW] !!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! * Plan for next week: - Monday: laser work [Jiangliang/Rodion] - Tuesday: HOM beam-based alignment [Tim/Philippe] - Wednesday: Flat beam [Philippe] - Thursday: Flat beam [Yin-e] - Friday: CTR bunch length [Daniel] Discussions: * Achievements of last week: - Monday/Tuesday/Thursday/Friday: Work on the laser occured [Jianliang/Rodion/Adrian] - the steping autocorrelator was fixed, and autocorrelation measurement were performed. The IR pulse width versus oscil- lator bandwidth was measured. The (assumed to be linear) depence yields [Delta T(IR)]/[Delta Lambda] = 2 ps/Angstr. meaning that the sensitivity of UV pulse length to bandwidth is about 1 ps/Angstr. This is a big effect especially with a usual oscillator bandwith variation of ~ 2-4 Angtroms. - some work on the CW autocorrelator was also attempted but its operation/setup is difficult. More work needed [this can be done in parallel to A0 operation] - Wednesday: [Daniel] work on the CTR autocorrelator: the autocor- relation are noisier than the one taken with the pyuroelectric detector. This was traced back to some high frequency (1 kHz) oscillation on the Golay cell signal. A filter has been borrowed from J. Bigs and will be installed/tested this week. * Discussion: - from now on the first day of the week will be dedicated to laser studies/work. * Tasks concerning hardware ACTION ITEM updated: Mon Aug 23 14:43:25 CDT 2004 H8/ calibration of upstream directional coupler and insulator (Markus need to speak to Tim and with Kai to schedule this STATUS?) H13/ Pulse stacker, what do we do? (Rodion) H21/ the laser uniformity problem can this be due to the new (since late summer) tight focusing in the doubling crystal area to improve conversion efficiency? On going work [Rodion] H28/ Problem with emittance measurement at X7 (Philippe 04/16/04) H29/ Need daily monitoring of the laser parameters (Jamie/Rodion 04/23/04) [OSCILLATOR BW AT 131.225.136.161:8000/~laser] H32/ Digital camera from SONY(?): camera sent back waiting for new ones [New CAM received/ tested by Markus OK] H33/ laser fluctuation since June 1st week [FIXED?] H34/ Need more work on power supply + devise a way to measure the current being put out to the magnet [Jamie] from Adrian Melissinos: NEEDED LASER STUDIES: 1. Study of oscillator bandwidth versus length of compressed pulse. Measure IR length using stepping autocorrelator [Done week of AUG 23rfd 2004] 2. beam profile (wavefront) studies both in IR and UV in laser room and on virtual cathode. Use spatial filters 3. study of doubling and quadrupling efficencies with old and new crystal, take a tuning curve POSSIBLE LASER UPGRADE PROJECTS 1. Measure IR pulse length before compression (use diode?) implement cw autocorrelation 2. Install new beamline between multipass and 2-pass -- install spatial filter, rebalance 2-pass amplifiers 3. Relay imaging UV from laser room to cave 4. _harware_: replacing all coolers with new system IV + use existing system III as back-up 5. pulse stacker studies, new pulse stacker R&D