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Experimental Log for the May 22-26 Kicker Test at the A0 Photoinjector

Monday 22 May

  • Arrive around lunch
  • A0 experienced a failed Traveling Wave Amplifier (TWA) this morning
    • Problems with replacement
    • Repair and testing ongoing
  • Start initial setup
  • DAQ checkout underway by Michael Davidsaver

Tuesday 23 May

  • Look at voltage induced on pulser due to beam
    • Find that coupling in both directions cause similar peak signal level
    • Directionally coupled signal has the exepcted doublet
    • Signal in the wrong direction has a peak and ringing
  • Pulser roughly timed in to look at beam
    • Find that DG535 precision delay generator cannot run at 1 MHz when programmed with large delay values
      • According to Jamie Santucci this is a known problem
      • JS provides a selectable cable delay box that will allow the DG535 delay to be shortened and full BW pulsing to take place.
  • Continued checks of DAQ by MD
  • Encounter persistent problems with TWA trips
  • Take initial timing scan data to identify pulse edges and peak of kick
  • Initial analysis of BPM data shows that BPM 7 data has offset positions which appear quantized. Suspect bit problem with that detector.

Wednesday 24 May

  • Kicker Timing: KTRIG0 = 1445 to have pulser in time

Thursday 25 May

  • DAQ program (/home/a0pi/davidsav/daqattack/daqattack) modified for better attenuation control algorithm
    • Observe better behavior
    • Note that attenuators have to be lowered significantly when kicking the beam
  • Scraping Issues: Appear to be scraping on the kicker at full kick strength
  • Adjust upstream corrector to improve kicker transmission with kicker on: HTAX14: -0.2 Amps --> 0.68 Amps
  • Attenuator Settings measured for
    1. straight through beam after adjusting quads Q2AX14 and Q3AX14
    2. With kicking on (and in time)
    3. Adjust upstream H corrector HTAXU2 from 0 to 2 Amps
    4. Take kicker out of time
    5. Repeat of 1
      BPM Atten NO kick Atten w/kick Atten w/kick & HTAXU2 Atten w/HTAXU2 only Atten NO Kick
      4 16 15 16 15 15
      5 16 15 15 15 15
      6 15 14 15 14 14
      7 16 16 16 15 16
      9 18 17 17 17 17
      10 13 15 14 12 12
      11 14 11 12 1 13
      12 17 16 17 2 17
  • Take run 81 with kicker out of time (KTRIG0 = 1446, 1 microsecond late)
  • Still having problems with the attenuator values displayed in the daqattack program (although BPMs appear to have valid. Appears to have been an initialization problem in the code.
  • Runs 82-84 are test runs
  • Run 85 is a straight through run (KTRIG0 = 1446)
  • Run 86 is a kicker peak run (KTRIG0 = 1445, Delay=15.5 ns, HTAXU2 = 2.0 Amps). High statistics.

  • 1400 MD puts in a reset fix if BPMs readback at 0 for 20 times, resets the BPM.
  • Inadvertently appended 64 events to end of file 86 on A0pi
  • Files 87-88 are diagnostics
  • Trigger cables and drive have been changed for the pulser which has changed the delay somewhat. Pulser delay now needs to be about 14.5 ns).
  • File 89 with kicker running. See huge beam fluctuations and trajectory change. Find that we have 9-cell problems.
  • Proceed with 9-cell adjustments and redo tune-up. (Current in quads = 1611)
  • Jamie arrives with pulse generator for driving FID pulser. This change going in simultaneously with 9-cell work. Puts delay timing back to the original 15.5 ns based on scope comparison of beam doublet and pulser waveform.
  • Files 90 and 91 are tune-up. Had to adjust spectrum analyzer magnet.
  • File 92 is a kicking test. Lost first two BPMs at end. Shows better stability so triggering was an issue
  • File 93 is a repeat of 92. Similar resolution.
  • Files 94 - xx are a timing scan.
    File KTRIG0 Delay HTAXU2 Comment
    94 1445 12.5ns 0.923 Setting up
    95 1445 12.5ns 0.923 Data point
    96 1445 13.5ns 1.758 Setting up
    97 1445 13.5ns 1.758 Data point
    98 1445 14.5ns 2.202 Setting up
    99 1445 14.5ns 2.202 Data point
    100 1445 15.5ns 1.758 Setting up
    101 1445 15.5ns 1.758 Data point
  • Observe possible 9-cell problem. Stop scan for diagnostics/re-tune
    • Cavity: Reset feedback loop and adjust phase
    • Possible cryogenics problem
  • Return to scan
    File KTRIG0 Delay HTAXU2 Comment
    102 1445 14.25ns 2.202 Data point
    103 1445 14.5ns 2.202 Data point
    104 1445 14.75ns 2.202 Data point
    105 1445 15.0ns 2.202 Data point
    106 1445 15.5ns 1.758 Data point
    107 1445 16.5ns 0.923 Data point
    108 1445 17.5ns 0.0 Data point
    109 1445 17.0ns 0.500 Setting up
    110 1445 17.0ns 0.500 Data point
    111 1445 18.0ns 0.0 Data point
    112 1445 19.0ns 0.0 Data point
    113 1445 20.0ns 0.0 Data point
    114 1445 21.0ns 0.0 Data point
    115 1445 22.0ns 0.0 Data point
    116 1445 8.5ns 0.0 Data point
    117 1445 9.5ns 0.0 Data point
    118 1445 10.5ns 0.0 Data point
    119 1445 11.5ns 0.0 Data point
    120 1445 12.0ns 0.500 Data point
    121 1445 12.5ns 0.923 Data point
    122 1445 13.0ns 1.250 Data point
    123 1445 16.0ns 1.250 Data point
    124 1445 13.5ns 1.758 Data point
    125 1445 14.0ns 2.202 Data point
    126 1445 14.5ns 2.202 Data point
    127 1445 14.4ns 2.202 Hi statistics on peak
    128 1445 14.5ns 2.202 Hi statistics run - RF problems interrupt. Feedback needed tweaking
    129 1445 14.5ns 2.202 Hi statistics run
    130 1445 14.5ns 2.002 Corrector scan
    131 1445 14.5ns 2.202 Corrector scan
    132 1445 14.5ns 2.402 Corrector scan

  • Pulse #2
    File KTRIG0 DelaySorted ascending HTAXU2 Comment
    135 1444 14.0ns 2.202 Burst scan
    133 1444 14.5ns 2.202 Burst scan - Possible RF problems
    137 1444 14.5ns 2.202 Burst scan - RF problems
    140 1444 14.5ns 2.202 Burst scan (unstable RF plot)
    142 1444 14.75ns 2.202 Burst scan
    134 1444 15.0ns 2.202 Burst scan - RF?
    138 1444 15.25ns 2.202 Burst scan
    139 1444 15.25ns 2.202 Hi statistics run
    141 1444 15.25ns 2.202 Burst scan
    136 1444 15.5ns 2.202 Burst scan
    143 1444 15.75ns 2.202 Burst scan

  • Pulse #3
    File KTRIG0 Delay HTAXU2 Comment
    144 1443 15.0ns 2.202 Burst scan
    145 1443 14.5ns 2.202 Burst scan
    146 1443 14.0ns 2.202 Burst scan
    147 1443 15.5ns 2.202 Burst scan (RF glitch plot)
    148 1443 16.0ns 2.202 Burst scan
    149 1443 15.0ns 2.202 Burst scan - high statistics
    150 1443 15.25ns 2.202 Burst scan - high statistics
    151 1443 14.75ns 2.202 Burst scan - high statistics
    152 1443 14.5ns 2.202 Burst scan
  • Stop to readjust LLRF and feedback
  • Re-check Pulse #3 and continue to pulse #1000
    File KTRIG0 Delay HTAXU2 Comment
    153 1443 15.0ns 2.202 Burst scan
    154 445 15.0ns 2.202 Burst scan
    155 445 15.5ns 2.202 Burst scan
    156 445 16.0ns 2.202 Burst scan - still seeing signs of RF feedback problems (plot)
    157 445 14.5ns 2.202 Burst scan
    158 445 15.25ns 2.202 Burst scan - high statistics (still signs of RF FB problems - plot)
    159 445 15.0ns 2.202 Burst scan - high statistics
    160 445 15.5ns 2.202 Burst scan - high statistics
  • Go to pulse #100
    File KTRIG0 Delay HTAXU2 Comment
    161 1345 15.0ns 2.202 Burst scan
    162 1345 15.5ns 2.202 Burst scan
    163 1345 16.0ns 2.202 Burst scan
    164 1345 14.5ns 2.202 Burst scan
    165 1345 15.0ns 2.202 Burst scan - high statistics
    166 1345 15.25ns 2.202 Burst scan - high statistics
    167 1345 14.75ns 2.202 Burst scan - high statistics
  • Straight Through Beam - Final check
    File KTRIG0 Delay HTAXU2 Comment
    168 1446 15.0ns 0.500 Garbage
    169 1446 15.0ns 0.000 Burst scan - high statistics
  • DONE

Friday 26 May

  • 18:00 Have received a few more hours of beam time thanks to Ray Fliller and Helen Edwards to make a final scan of the primary pulse from the FID pulser
  • Files 170-173 were tune up files
    • Adjust Q2AX14 and Q3AX14 quads to optimize beam through kicker
    • Adjust HTAX12 to adjust position in kicker so that we don't scrape with a full kick while still having good throughput with no kick.
  • Encounter more RF feedback problems and Ray decides to reboot the LLRF control computer
    • Unable to make the RF feedback stable.
    • The problems are found to be unrelated to beam in the cavity.
    • Giving up for today.

Saturday 27 May

The present intention is to leave the FID pulser at FNAL for at least a few weeks and try some remote testing. This will be more efficient for the long term if we can make it work.

Take advantage of a couple free hours before today's flight to take some scope data with the +/-1kV FID pulser. The present triggering configuration and signal configuration are as follows:
  • Triggering
    • 1 MHz A0 trigger signal is the input through an RG58 delay cable (of order 100 ns???) followed by a cable-based delay box with 32+128 ns of delay setting
    • The output of the delay box goes through a 4ns RG58 cable to a Stanford Research Systems Model DG535 digital delay/pulse generator
    • DG535 output is fed through an 8ns RG58 cable to a Phillips PM5781 programmable pulse generator (125 MHz) and from there to the FID pulser via a (~6ns) cable RG58 cable
  • Signal
    • Heliax (1/2") cable from the output of the FID pulser to the stripline kicker
    • 44 ns of RG213 cable from stripline output to attenuator stages (34dB JFW 50FH-034-5 power atten followed by TexScan FP-50 6dB atten)
    • After the attenuators, 16ns of RG58 cable takes the signal to another TexScan FP-50 6dB attenuator on the front of the scope
    • Scope is triggered off of the Sync Out signal from the FID pulser
  • All traces taken with a LeCroy LC574AL 1 GHz Oscilloscope

Scope traces taken after the output of the FID +/-1kV pulser:
  • 12:16 First pulse (239.1 ns trace delay).
     D003.TIF 
  • 12:30 First pulse with signs of occasional 0.25 ns glitches.
     D004.TIF 
  • 12:34 Second pulse (1.2357 microsec trace delay) showing signs of +/- 0.25 ns jitter.
     D005.TIF 
  • 12:38 Third pulse (2.2320 microsec trace delay).
     D006.TIF 
  • 12:40 Fourth pulse (3.2291 microsec trace delay).
     D007.TIF 
  • 12:42 Fifth pulse (4.2259 microsed trace delay).
     D008.TIF 
  • First 10 pulses in train in accumulation mode.
     D009.TIF 
  • First 6 pulses with shifted trigger to show that we are sampling at start of train.
     D010.TIF 
  • 10 pulses with 99.7 microsecond delay to show approx. pulse 100 in train.
     D011.TIF 
  • 12:53 10 pulses with 0.9999 ms delay to show approx. pulse 1000 in train.
     D012.TIF 
  • 12:58 Tenth pulse (9.2109 microsec trace delay).
     D013.TIF 

Switch to internal triggering of the pulser. Trigger off first positive pulse in burst. Scope traces:
  • 13:14 First pulse.
     D014.TIF 
  • 13:16 Second pulse (339.3 ns trace delay).
     D015.TIF 
  • 13:19 Third pulse (681.4 ns trace delay).
     D016.TIF 
  • 13:21 Fourth pulse (1.0025 ns trace delay).
     D017.TIF 
  • 13:25 Fifth pulse (1.3638 ns trace delay).
     D018.TIF 
  • 13:29 10th pulse (3.0714 ns trace delay).
     D019.TIF 
  • 13:33 30th pulse (9.9016 ns trace delay).
     D020.TIF 
  • 13:41 First 6 pulses with 0.2 microsec/division.
     D021.TIF 

Desired future scan

  • Fast scan over primary peak (approx. 150 shots per point)
    File KTRIG0 Delay HTAXU2 Comment
    174 1445 3.5ns 0.000  
    175 1445 8.5ns 0.000  
    176 1445 9.5ns 0.000  
    177 1445 10.5ns 0.000  
    178 1445 11.5ns 0.600  
    179 1445 12.5ns 1.800  
    180 1445 13.0ns 3.000  
    181 1445 13.5ns 3.600  
    182 1445 13.8ns 4.000  
    183 1445 14.0ns 4.200  
    184 1445 14.2 ns 4.200  
    185 1445 14.4 ns 4.200  
    186 1445 14.6 ns 4.200  
    187 1445 14.8 ns 4.200  
    188 1445 15.0 ns 4.200  
    189 1445 15.2 ns 4.200  
    190 1445 15.5 ns 4.000  
    191 1445 16.0 ns 3.600  
    192 1445 16.5 ns 3.000  
    193 1445 17.5 ns 1.800  
    194 1445 18.5 ns 0.600  
    195 1445 19.5 ns 0.000  
    196 1445 20.5 ns 0.000  
    197 1445 25.5 ns 0.000