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    User name Jin Huang

    Log entry time 14:33:53 on July 05, 2010

    Entry number 330225

    This entry is a followup to: 330172


    keyword=RHRS Optics Run Checks

    Two batch of RHRS optics run was analyzed with Yi's hypernuclear RHRS optics database. Data was taken on Ta target with raster off. Run numbers are * 1718-1720: Sieve in * 1735: Sieve out Agressive positron PID cut (R.cer.asum_c>300 && R.tr.n==1 && (R.ps.asum_c+R.sh.asum_c)/(R.tr.tg_dp+1)>500) was applied to study sieved runs. First figure below show vertex correlation (vz:tg_ph). Sieve out run show a clear stripe with PID and with out PID cut. (total VDC hit was very low in this run with T3 trigger. only 2% event have track, any problem?) However, positron in sieved in runs spread into larger region. Second figure shows tg_th:tg_ph correlation for sieved runs. With foil target, they should be corresponding to angular acceptance and sieve parterns. However, for two dp cuts, no sieve hole are found. The second plot is cut out 0.3% on central dp. It's similar momentun region like Halog 328374 (http://www.jlab.org/~adaq/halog/html/1006_archive/100626100456.html), which identied clear sieve holes on LHRS with elstic electron and Yi's hypernuclear LHRS optics database. As conclusion, no sieve hole was found at first look. More study will follow up

    A copy of this log entry has been emailed to: riordan, vasulk, yqiang, toron

    Comparison of VZ:tg_ph correlation. Left: Sieved run (1718-1720) with Positron cut; Right: Sieve out run (1735) with no pid cut

    Search for Sieve (tg_th:tg_ph) with Sieved run (1718-1720) and Positron cut. Left: |dp|<4%; Right: |dp|<0.15%