GTS meeting 3 28 17

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  1. Data can be found here: [1] [2]
  2. There is an indication of problem with first solenoid


  • Conditioned Gun at 300 kV with solenoid at 0 to 300 A, left to do it at: 325, 350, 375, and 400 A. Two currents, 350 and 400 A, we attempted before but we will repeat.


  • Attempting to center solenoid by moving magnet:
  1. Moved solenoid 1.5 mm to beam left - closer to active area at 3:00 o'clock
  2. Moved solenoid 3.2 mm (from center) to beam right. In both cases no improvement by looking at beam on ITVGT03 (first viewer) while scanning the solenoid between 10-150 Amps. Beam can be seen on edge of viewer rotating clockwise then drifting towards -45 degrees (lower-right) as solenoid current approaches 150 Amps.


  • Magnet was moved back to original center position by S&A. We are waiting on final survey report.


  • Attempting to center solenoid by moving active area:
  1. Moved active area to 9:00 o'clock, 12 o'clock and 6 o'clock. In the three cases no improvement by looking at beam on ITVGT03 (first viewer) while scanning the solenoid between 10-150 Amps. beam behaved similarly at the four laser positions (including the initial 3 o'clock).


  • Laser Newport powermeter is now at the exit window side of the gun


  • Laser tables are covered


  • Plan for this week (March 27, 2017):
  1. Monday - Friday: open in morning to install second part of beamline but close in afternoon to run beam
  2. Week of April 3rd: open all day for beamline bake. Turn ON the extractor gauge in Gun HV Chamber. Use GN2 heater to send 250 C hot gas through the water lines of the FCup to degas. Instrument beamline.


  • What we are working on now:
  1. Still trying to center the gun solenoid
  2. Do we want to keep the anode biased at +280 V all times (and while running beam)?


  • Emittance vs Gun HV:
  1. Mamun at 3 o'clock: media:Emittance_GunHV_3468399.xlsx [3]
  2. Yan's Summary: media:BeamEmittancevsHV.xlsx [4]


  • These are the simulation tasks that we should try:
  1. Simulate beam rotation at: B=0 G (0 A), B=170 G (50 A), B=340 G (100 A), B=510 G (150 A), B=680 G (200 A), B=850 G (250 A), B=1020 G (300 A), B=1190 G (350 A), B=1360 G (400 A)
  2. Simulate emittance vs Gun HV