Difference between revisions of "GTS meeting 3 28 17"

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(Created page with " * With both solenoids at +2.0 Amps, the solenoid field direction is pointing downstream along the beam path. The field of the magnetized gun solenoid is pointing out of the p...")
 
 
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* Sajini Wijethunga, ''Comparison of the focal length of the solenoid'': [[media:focal_length_and_emittance.pdf]]
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# Data can be found here: [https://logbooks/entry/3468314] [https://logbooks/entry/3468315]
 +
# '''There is an indication of problem with first solenoid'''
  
* With both solenoids at +2.0 Amps, the solenoid field direction is pointing downstream along the beam path. The field of the magnetized gun solenoid is pointing out of the photocathode into the downstream direction.
 
  
 
* 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.
 
* 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.
  
* MCRGT01 corrector was firmly fixed to beamline using Al holders.
 
  
* Plan for next week (March 27, 2017):
+
* Attempting to center solenoid by moving magnet:
# Monday, Tuesday and Wednesday: open in morning to install beamline but close in afternoon to run beam
+
# Moved solenoid 1.5 mm to beam left - closer to active area at 3:00 o'clock
# Thursday and Friday 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.
+
# 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.
# Week of April 3rd: finish bake and instrument beamline
+
 
 +
 
 +
* 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:
 +
# 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):
 +
# Monday - Friday: open in morning to install second part of beamline but close in afternoon to run beam
 +
# 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:
 
* What we are working on now:
# Put a laser Newport powermeter at the exit window side of the gun using a RS232 for controls
 
# Put Al cover around laser tables
 
 
# Still trying to center the gun solenoid
 
# Still trying to center the gun solenoid
 
# Do we want to keep the anode biased at +280 V all times (and while running beam)?
 
# Do we want to keep the anode biased at +280 V all times (and while running beam)?
  
* Yan and Mamun are sharpening their emittance measuring skills - now, we define emittance with no π, see [https://wiki.jlab.org/ciswiki/index.php/GTS_meeting_1_3_17]
 
  
* Yan and Mamun have been measuring QE versus Gun HV: 50, 100, 200, 300 kV - see GTS logbook for preliminary results
+
* Emittance vs Gun HV:
 +
# Mamun at 3 o'clock: [[media:Emittance_GunHV_3468399.xlsx]] [https://logbooks/entry/3468399]
 +
# Yan's Summary: [[media:BeamEmittancevsHV.xlsx]] [https://logbooks/entry/3468623]
 +
 
 +
 
 +
* These are the simulation tasks that we should try:
 +
# 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)
 +
# Simulate emittance vs Gun HV

Latest revision as of 17:14, 28 March 2017

  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