Spring 2019 Primex

Draft Run Plan for the PrimEx-D Run for first few weeks

(Updated: 01/10/2019)

Overview

The goal of the experiment: extract the η rad. decay width with as high accuracy as possible.

How: from the measured absolute diff. cross sections.

The method:

1. measure the Compton diff. cross section on 5% Be target;
2. compare with the known theoretical cross section and extract the so-called “setup normalization constant-Be” (ideally it should be “1”, this number will be sensitive to photon flux and efficiencies of CCAL and FCAL);
3. measure the same Compton diff. cross section on ⁴He target;
4. compare with theory prediction obtained with estimated ⁴He target density and with the “setup normalization constant-Be”. This new number will be used to normalize our dN(η)/dθ to get the cross sections in μb/Sr.

Run Plan

1. With empty target:
   • Remove the LH2target cell (if ST needs to come out then remove it also). day shift, 7am - ~4pm
   • Checkout and calibration of CCAL 2 shifts ~4pm – 7am

1. With Be target:
   • Install Be target, ST possibly in w/o cabling and survey. Day shift, 7am – ~4 pm
   • If Be-target is ready, run Compton ~5 shifts ~4pm – 7am

1. With ⁴He target:
   • Work on target, remove Be (if needed remove ST) day shift, 7am – ~4 pm
   • If ⁴He target is not ready, run “Be empty” target (ST is back) 2 shifts, ~4pm – 7 am
   • Work on target install ⁴He, ST cabling day shift, 7am - ~4pm
   • Setup checkout with beam 2 shifts, ~4pm – 7am
   • Continue work on ⁴He, survey day shift, 7am - ~4pm
   • If LHe4 still empty, run “⁴He empty” 2 shifts, ~4pm – 7am
   • If “empty” is finished, fill ⁴He target and run LHe4 Compton
   • Prepare the setup and run for η-Primakokf ~4pm – April
   • Keep analyzing data