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HPS Beamline Commission Document v1 October 20, 2014 HPS beamline commissioning document v1.0.docx
Beamline Alignment with magnets at 95in. separation:beamline_Mar032014.pptx
Beam trajectory through pair spectrometer magnet , from simulation.
Engineering drawings of beamline and components: https://userweb.jlab.org/~zarecky/Dark%20Matter%20file%20directory.htm
7/26/2011 slides from Stepan including plan and survey positions of vacuum chamber: BeamLine_updates.pptx
Beamline photos are available: Beamline.pptx
See Calorimeter for ECal-specific docs.
Presentation of Beamline update at Wednesday morning, 27 March 2013, meeting Beamline 27 March 2013.ppt
ECal vacuum flange: beam gap vacuum chamber, honeycomb
The magnetic field maps used for simulation and reconstruction are derived from TOSCA simulations combined with PRIMEX measurements of the fringe fields. That procedure is described here. This results in the following files:
These maps represent one eighth of the field volume, assuming symmetry for the other seven octants.
The file format is:
X Y Z BX BY BZ
with units of cm and Oersteds.
These files are then converted into a format appropriate for the slic simulation program and the hps-java reconstruction code using the following prescription:
First, determine the field setting required for the energy of the beam.
Find the closest fieldmap calculation in the above list and determine the scaling factor to bring the central value of the fieldmap into accord with the desired setting.
Scale, unfold and convert units of the txt file into a file which can be used by slic and hps-java using the following command:
java -cp ~/.m2/repository/org/hps/hps-distribution/3.11-SNAPSHOT/hps-distribution-3.11-SNAPSHOT-bin.jar org.hps.util.UnfoldFieldmap < fieldmap > < scaling factor >
The resulting file, out.dat, should be renamed to preserve the provenance, e.g.
125acm2_3kg_corrected_unfolded_scaled_0.7992.dat (1.056 GeV running)
209acm2_5kg_corrected_unfolded_scaled_1.04545.dat (2.3 GeV running)
The fieldmaps are archived at http://www.lcsim.org/resources/hps/fieldmap/
For HPS fieldmaps are on GitHub: https://github.com/JeffersonLab/hps-fieldmaps.git
Document: https://wiki.jlab.org/hps-run/images/c/c6/Chicane_settings.pdf
For 2019 run: Analyzing magnet current: ~1609 A, Magnetic Field read back: -9668.1±21.3 G
(Method: take the MYA read back for the Analyzing Magnet (HPS:LS450_2:FIELD) for the period 2019-07-26 19:08 until 2019-09-08 21:26. For each run, search for a value before the run_start time. Compute average and steve for those values that are < -9000)
Papers: