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The figure above shows information from the BPM HA34 taken during the shot on the afternoon of Monday August 16, 2004. The traces are

The units of position are mm. The units of bpm sum signal are Echotek units.

The scales for the positions and for IBEAM are on the left. The scales for the intensities and for FBIANG are on the right.

See below for instructions on how to access this information in the datalogger.

Notes:

1. Proton position.
   • The structures about 17:07 to about 17:17 are the injection bumps. You can extract this data from the data logger and zoom in on this time to see them more clearly.
   • The helix opens at about 17:22 .
   • There are glitches in proton position when Pbar injections take place. Are these planned bumps?
   • The proton motion during the ramp, squeeze and start of collisions, near 17:50, mirrors the pbar motion ( see below ).
2. Pbar position.
   • Plotted with same full scale range as proton position.
   • The trace starts with the first anti-proton injection, around 17:26. ( Except for the noise discussed below ).
   • Why does the anti-proton position appear to change as each group of 4 bunches is injected?
     • The cancellation of the proton contamination on the pbar cables uses a stale calibration.
     • When the antiproton current is high, the residual contamination is small part of the total signal. When it is low, the residual contamination makes an important contribution to the total signal.
     • So that later times are the correct postion.
     • This will be be improved.
   • Glitches are visible at each pbar injection. Are these planned bumps?
   • Pbar motion during ramp, squeeze and start of collisions near 17:50 mirrors the proton motion.
   • What are the blue noise dots at an antiproton position near 1 or 2 mm, which appear at times before 17:26?
     • There are no pbars in the machine at this time so the pbar signal should be below threshold.
     • The system is designed so that the position is offscale when the signal is below threshold.
     • But the cancellation of the proton contamination on the pbar cables uses a stale calibration. So sometimes the pbar signal is above threshold to declare the pbar position valid.
     • The thresholds are being adjusted and the calibration is being improved.
3. Proton sum signal.
   • Compare with T:IBEAM.
   • You can extract the data from the datalogger and zoom in on the proton injection to see the structure at injection.
   • The step in A+B near 17:50 is an artifact due to the change in energy during the ramp. It could be calibrated out be we have chosen not to.
4. Antiproton sum signal:
   • Compare with T:FBIANG.
   • There are 9 antiproton injections but you need to look carefully to see it. There is a long pause between the 8th and 9th injections.
   • The step near 17:50 is an artifact due to the change in energy during the ramp.
   • You can extract this data from the datalogger and zoom in on the time before pbar injection in order to assess the quality of the cancellation of the proton contamination on the pbar cables.

Access to this Data in the Data Logger

1. Start the D44 console program.
2. Select the time interval 16-Aug-2004 17:07:00 to 16-Aug-2004 18:00:00
3. Select user "Rob Kutschke", near the bottom of the list.
4. Recall the saved configuration "FirstShot3".
5. Click in the appropriate field to make the plot. The data comes from a 15 Hz data logger, so it may take a while. This speed is necessary to catch the fine structures during injection.
6. In its present configuration, the datalogger will store the data for about 36 days before it wraps.

The same information is also available for the beam positions and intensities at VA35, with the obvious ACNET variable names.

In the hours before this shot, the configuration of the system was changed frequently so data before this time is not meaningful. Data for about the next 24 hours is meaningful but at any time after that we may be performing studies and the data will be unreliable.