Beam and Raster Checkout for A1n/d2n (Short Procedure)

Establish beam in the hall

 Goals 
 - Using "Target Out" location, make sure beam reaches beam dump without hitting anything.

Initial Raster check with YAG Viewer

 Goals 
 - Establish beam to be roughly centered in beam pipe by locating it on YAG viewer just upstream of target.
 - Turn on Raster and verify beam profile expands as expected.
   
 Setup 
 - Beam Current:   Tune Beam (Viewer limited)
 - Target:         No Target
 - Raster:         Off; 5mm diameter

 Procedure
 - Call MCC to insert YAG viewer on Hall C superharp girder.
 - start with raster off, MCC should post a picture, verify beam spot roughly centered.
 - if the beam energy has changed, check that on the Hall C Raster Control GUI it is initialized for the correct beam energy (at the top of the GUI).
 - request raster on:  5mm diameter
 - ask MCC to post a video of the viewer. It should show beam spot on viewer expanding larger than raster off case, and the beam spot size should show a breathing pattern. 
 - MCC will retract viewer after check is done.

 - An example of what to look for can be found in https://logbooks.jlab.org/entry/3764451
 - Another example posted in elog: https://logbooks.jlab.org/entry/3768480
 - Here is an example of how to interpret the images on the YAG viewer: https://logbooks.jlab.org/entry/3749551 (taken during initial beam checkout in December 2019).

Harp scans

 Goals 
 - Verify operation of Harp scanners w/ beam.
 - Establish acceptable beam profile. 

 Note
 - We need sigma=100-300um. 
 - If sigma is larger than 300um, ask MCC to tune beam. 
 - Once sigma reaches below 350um, call RC for advice on whether we should accept the beam.

 Setup 
 - Beam Current:   5 uA CW
 - Target:         No Target 
 - Raster:         Off

 Procedure
 - Verify that the raster is OFF for the harp scans at the target (3H07) 
 - Ask for harp scans with IHA3H07A and IHA3H07B
 - verify beam profile (nominal 100--300um sigma in peak 3) on at least one scanner on Hall C upstream beamline (good to check 3H07A/B)
 - One can go more sophisticated and calculate the beam size at the target, see algorithm in

Check Beam Positions

 Goal 
 - Do this if nominal beam positions are already established.

 Setup 
 - Beam Current:   5 uA CW
 - Target:         No Target

 Procedure
 - With "No Target" position, ask for 5uA CW and verify beam position with established nominal position

Target/Beam centering, Raster checkout

 Goals 
 - Establish beam position on target, check/confirm raster size

 Setup 
 - Beam Current:   5-10 uA CW
 - Target:         Double Carbon Hole
 - HMS setting: check run plan
 - SHMS setting: check run plan

 Procedure
 - Note:  DAQs should be running and double carbon hole target is in place
 - Online shift crew will proceed with program below.

 - Image Carbon Hole target using Raster current pickoffs vs. raw trigger rates in SHMS and/or HMS
 - Target:    Double Carbon Hole
 - Current:   5 uA CW
 - Raster:    5mm diameter
 - Run DAQ on SHMS / HMS
 - Set PS1=0 and all other PS=-1 to ensure DAQ is dominated by scintillator triggers (i.e. "3scintillators out of 4" or "3/4" triggers)
 - Run the online analyzer and look at the 'Fast Raster' panel of the online GUI:
 - Locate the hole in the 2D intensity histogram. A rough z cut should be included in the script to show up- and down-stream carbon hole separately.        
 - NOTE: if the beam energy in standard.kinematics is not up to date, the distance scale on the 2D histogram will be wrong

 - Center Beam on using Double-Carbon-Hole Target:
     - Iterate until the hole is clear, and is centered in the circular raster pattern for both up- and down-stream carbon foils
       - Adjust beam position
       - Re-run the online analzyer on the new file(s) to see the effect of a raster size change and/or beam position change.  Make sure changes are logged in the CODA start-run entries!
 - Estimate raster dimensions against Carbon Hole diameter (known to be 1mm).

 - Make sure we run at 5uA CW and run harp scan on target girder and verify width of the harp is consistent with 5mm diameter raster setup.
 - For an example of complete beam centering procedure using carbon hole, see https://logbooks.jlab.org/entry/3749551