Measurements

From Hall A Wiki
Revision as of 06:20, 12 November 2022 by Cisbani (Talk | contribs) (→‎Recent polarization measurements)

Jump to: navigation, search

<< Back

Target Polarization Angle Conventions

Be VERY clear here about the convention (beam-right/left/up/downstream) vs 0, 90, 180, 270)
for each run period.  More notes and references to log entries are better.

Taking an NMR Measurement

  1. Make sure that the holding field settings are correct for whatever magnetic field settings you're working with.
    1. Note that if you have to change the holding field, you will then need to restart the NMR GUI once the holding field is in its new configuration.
    2. This can be done by pressing the red "stop" button in the top left hand corner and then the "run" button.
  2. Call MCC to mask the beam so that you can move the target to the "pickup coils" position.
  3. Make sure that the NMR GUI settings are correct. The high field should be 34G and all of the sensitivities should be 100. Make sure that the calibration constant is correct.
  4. In the white box on the bottom left hand side of the NMR GUI you can write a comment with convection and B field settings.
    1. Example of a comment would be "120W 245C 9V 5G/s 0.2Vrms bb/sbs on/on"
  5. Press the green "Start" button.
    1. A window will pop up that should contain the comment that you just wrote. If the comment isn't there do NOT press cancel!! Just rewrite your comment. You should also make sure the NMR constant is correct. And that it's recording for the correct target cell.
    2. Press the "Go ahead" button.
  6. Once the sweep is done, the number in the top right under "Polarization %" is the polarization that you should record in a log entry.
    1. Make a log entry titled "NMR Measurement 100%" (with the polarization percentage from the NMR sweep you just did) with a screenshot of the NMR controls GUI.
    2. Include a general status of the beam for the past couple of hours in your log entry.
  7. Move the target back to the original position.
  8. Record at the bottom of this page the date, time, and polarization of your measurement with a link to the halog entry.

Polarization Calibration Data

ADD LIST OF CALIBRATION RUNS HERE
AND A TABLE OF RELEVANT CALIBRATION CONSTANTS TO USE FOR WHAT RUNS
Cell Calibration
Type 		SHMS Angle
/degree 		SHMS Momentum
/GeV 		Field Direction
/degree 		Calibration Results Status Oven Temperature
/°C 		Log#
Hunter EPR-NMR 11 7.5 90 5.24 %/mV Done 200 3839939
Hunter EPR-NMR 18 5.6 90 undone 205
Hunter EPR-NMR 11 7.5 270 undone 208
Hunter AFP Loss 14.5 6.4 90 1.25%/Sweep Done 200 3840618, 3840143, 3840618

Recent polarization measurements

After doing an NMR sweep, record the date, time, and polarization percentage. Link to a log entry in which you include a screenshot of the NMR Field Sweep Control Program.

Retrieved from "https://hallaweb.jlab.org/wiki/index.php?title=Measurements&oldid=44006"