• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name ulmer

    Log entry time 13:38:13 on June17,2002

    Entry number 86276

    This entry is a followup to: 86223


    keyword=Remeasure 1H(e,e'p)

    Given that the Left arm was moved slightly and then back again between the Q2_acc and Q2_f10r points, we should remeasure 1H(e,e'p) again at the Q2_f00 kinematics.
    This MUST happen BEFORE any movement of the Left arm. The main motivation is that we use the Left arm with sieve and 1H(e,e'p) to establish the q-vector. Then all protons are measured relative to this. This is especially important for the LT interference measurements since one must be sure to sample symmetrically about the q direction. So here's my suggested plan:

    1. Depending on time constraints, after finishing a left/right combination, cycle the Right spectrometer fields (Q2/Q3) and set the right momentum and angle to the f00 kinematics (NO CHANGE OF LEFT ARM - NEITHER ANGLE NOR MOMENTUM!!).

    2. Load the LH2 - 15 cm target (hydrogen). Make quick measurement with both collimators OPEN.

    3. Make a measurement with Left arm SIEVE and Right arm OPEN.

    4. If time permits, repeat #3 with 4 cm LH2 target.

    There is no need to run 2H here, since it's the kinematic constraints from 1H(e,e'p) that we're interested in. There is also no need to redo the "optics" measurement (i.e. 9-foil carbon) since we have many measurements of this already with the Left arm where it now stands. Naturally, the main time hit is the cycling of the bloody Right arm dipole.