February 11, 2015 - CIS Group Meeting

CEBAF Startup

Laser Program

A = 50uA @ 125 MHz or 100uA @ 250 MHz

B = 499

C = 250

Laser setup

No spare amps, 4-6 weeks from IPG for two replacement amps

Replace 2m (FWHM~1mm) spot lens with 1.5m (FWHM~0.4mm) lens

Phase flip

Make divider box less sensitive to EMI?

Phase monitoring to keep phases between 3 lasers

Analog gain switching at 250 MHz

Change the laser phase

When we change the frequency use 0I04 viewer to check/set phase

Command line EPICS control sufficient now, Mike Johnson still working it

Tomas can provide a ~2ns delay cable

John can DAC control a phase delay ~2ns

To Do

We will learn at separators if we can flip A/D or D/A order

We will decide by summer time a final system configuration

SF6 tanks

Bubba repaired SF6 leak, pumping now and check

Test various insulators

black = bulk resistivity = shorty R28 (ordered R30, but too little resistivity so too much current draw)

white = coated with black = suffer similar resistively too low, but at least constant

white + spiral = coated with black but sand-blasted spiral (16 feet path length, so longer length of resistor)

tracking on R350 ceramic in SF6 tank possibly due to low SF6 pressure

Electrode

Nb = pressed, polished?

Steel = welded, looks good, not polished

Wave anode, but not the spider support

Va beamline

Shop making end plates

Ordering new shell + using previous 848 turn coil

Yan figure out what fields are needed for the solenoids

Layout

Joe Gubeli generated mechanical model from preliminary Elegant layout, will study mechanical strength

HDIce group working on monte carlo model of backgrounds by dump

Meeting will be setup to advance layout of gun + prep chamber