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Jefferson Lab Experiment E91-016

3He(e,e'K+) 7-degree lab

Item Task Log Entry
  For a beam energy of 3.245 GeV set the spectrometers to:
  Momentum (GeV/c) Angle (degree) Trigger Collimator Prescaling
HMS -1.576 15.00 e--PID pion PS1=
SOS +1.290 20.30 K+-PID large PS2=
Follow the proper prodecures for setting the magnets:
  • HMS current&field settings: 

    •                 cdaqs1> ~cdaq/FIELD/field99 
                     Input HMS momentum in GeV, electron is negative. 
                    -1.576 
                     Set current for Q1 =     204.62842198462 amps 
                     Set current for Q2 =    -162.61167176023 amps 
                     Set current for Q3 =     79.874587716980 amps 
                     Set NMR for Dipole =   -0.43187710604559 Tesla
    Set HMS Quads 200 A above required setting and then go down to nominal setting
  • Degauss SOS for protons and then go up to nominal setting
  
  Ask for 10 uA beam. Determine SOS 3/4 rate and then increase current such as to give 600kHz SOS 3/4 rate.  
  Take a short run. Adjust prescale factors such that HMS and SOS singles rates are approx. 5% each. Determine deadtime for this setting.  
Take runs with 1M triggers.  
  Approx. once every 8 hours take data on the dummy target, with I=xx uA. Take 1/10 of the charge accumulated on the helium target since the last dummy runs.  
  Get singles data with Quintar and sieve slits. SOS trigger 3/4 no PID. HMS trigger stays e- PID. Get enough statistics to get roughly 100 events for each hole from each target. For SOS cut on pions. Schedule this when somebody is around who actually can determine that.  
Hall C Operating Manual
Last updated 11/15/99
By Jörg Reinhold(reinhold@fiu.edu)