Beam and Raster Checkout for A1n/d2n (Long Procedure)
From HallCWiki
Jump to navigationJump to search
Establish beam in the hall
Goals - Using "Target Out" location, make sure beam reaches beam dump without hitting anything.
Initial Raster checks
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: Viewer limited (Tune Beam) - Target: No Target - Raster: Off; 5mm diameter
Procedure - Insert YAG viewer on Hall C superharp girder - start with raster off, 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 - watch beam spot on viewer and verify Raster's basic functionality - Retract viewer
Bullseye scan (Brad and JP please fix this)
Goals - Verify operation of Harp scanners w/ beam. - Establish acceptable beam profile (nominal 100--500um sigma)
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--500um sigma) on at least one scanner on Hall C upstream beamline (good to check 3H07A/B)
Harp scans
Goals - Verify operation of Harp scanners w/ beam. - Establish acceptable beam profile (nominal 100--500um sigma)
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--500um sigma) on at least one scanner on Hall C upstream beamline (good to check 3H07A/B)
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.