[Lad_hallc] [EXTERNAL] Re: Runplan final draft

[Weinstein, Lawrence B.]

A few questions.  #6.4 is the  really important one.


  1.   item 2.1: what is the difference between setting PS6=0 (accept all, no prescale) and other triggers ps = 1?  What prescale factor does ps=1 correspond to?
  2.  item 2.4: can we take enough data at some of the settings (especially 5) to measure the H(e, e’) cross section?  It is always good to be able to normalize the spectrometers.
  3.  p6: GEM optics
     *   is there an advantage to inserting the sieve for the GEM foil optics run?  It will kill our event rate.  We will already know the HMS optics so we will know the electron angles.
     *   Where is the GEM located at this run?  Forward or back?  Can it see the protons?
     *   what trigger will we use?  The SHMS trigger should be ps = -1
     *   should we check the reference bar timing at this time?  should it be on?
  4.  item 2.5: where is the reference bar placed?  Where is the GEM at this time?  If both are forward, we can do this during the GEM optics check by changing the target from multi-foil to LH2.
  5.  item 2.7:
     *   should we set the ps so that ps2 = 0 and ps4 = 0? Then we can take single arm data from both HMS and SHMS (luminosity scan).  Item 2.6 specified ps1 = ps2 = 0.
     *   is the raster on or off?
  6.  item 3.1 (and similarly for 3.2 and 3.5)
     *   Do we run raster off when beam current is 1 uA or less?
     *   how do we set ps1 and ps3?  1% or 10% each?
     *   #7:  I assume it is "<= 2 kHz”
     *   what determines the maximum luminosity that we can run at?  This specifies trigger rates less than 1 kHz in each arm.  Why should we change the prescalers to achieve this rate, rather than the beam current?
     *   #11: how long should the dummy run be?
  7.  item 4.1: we are using the carbon multi foil for optics calibration for the GEMs and HMS/SHMS.  Do we use this target for LAD at all?  These are 55 mg/cm^2 target foils.  There would be significant material (>500 mg/cm^2) for the LAD bar at 90 degrees and the two bars on either side of it.
  8.  there is no item 8

- Larry

On Mar 19, 2025, at 10:32 AM, Florian Hauenstein <hauenst at jlab.org> wrote:

EXTERNAL to ODU: This email is not from an ODU account. Do not click links or open attachments unless you recognize the sender and know the content is safe.
Dear all,

please find attached the final draft  from Dien, Holly and me of the run plan.
The amount of production running in each setting is not fully set in stone since it depends on the observed statistics.
Please let us know your comments as soon as possible.

Best,
Florian
<LAD_Runplan-5.pdf>_______________________________________________
Lad_hallc mailing list
Lad_hallc at jlab.org<mailto:Lad_hallc at jlab.org>
https://mailman.jlab.org/mailman/listinfo/lad_hallc 

Lawrence B. Weinstein
University Professor and Eminent Scholar
Physics Dept
Old Dominion University
Norfolk, VA 23529
weinstein at odu.edu
https://urldefense.proofpoint.com/v2/url?u=http-3A__www.lions.odu.edu_-7Elweinste_&d=DwIGaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=6m0gxcB4MAfTXtDSby1O2f94ujT0p-ToKeSFcw9-d5I&m=7fSJRAxIIOEZjNQWix5Kl4ecEgQ5mhA8Ja13kwR5gnqTsGjVblHMqsOIhIR7F8K6&s=0gWp6pbQYB5wBcsTI9kdcb0yjYeH_KaYGsUBKzmU8lM&e= 
757 683 5803








-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/lad_hallc/attachments/20250319/dec13f68/attachment-0001.html>