Difference between revisions of "Beam and Raster Checkout for A1n/d2n (Short Procedure)"

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=== When should we do a short beam checkout? ===
+
== When should we do a short beam checkout? ==
  - After beam studies.
+
* After beam studies (typically on Tuesdays)
  - If for some reason the accelerator has been down for a "significant"
+
* If for some reason the accelerator has been down for a "significant" period of time (say, more than ~8 hours)
    period of time (say more than ~8 hours).
+
* If anything "significant" has changed in the beam line and you are not sure if it will affect the position or profile of the beam delivered to the hall
  - If anything "significant" has changed in the beam line and you are
+
    not sure if it will affect the position or profile of the beam
+
    delivered to the hall.
+
  
=== Establish beam in the hall ===
+
== Procedure ==
  '''Goals '''
+
  - Using "Target Out" location, tuned beam only, make sure beam reaches beam dump without hitting anything.
+
  
=== Stripcharts ===
+
[[File:Checkout_stripchart.png|thumb|upright=0.5|right|alt=Beam restoration stripcharts|Beam restoration stripcharts]]
[[File:Checkout_stripchart.png|thumb|upright=1.0|right|alt=Beam restoration stripcharts|Beam restoration stripcharts]]
+
[[File:Targetcontrol.png|thumb|upright=0.5|right|alt=Target motion control|Target motion control]]
 +
=== Open Stripcharts ===
 
* You should monitor the beam position, mode, and current during this process.
 
* You should monitor the beam position, mode, and current during this process.
 
* Open a terminal and run go_beam_recovery_stripcharts. You should see something like the image to the right.
 
* Open a terminal and run go_beam_recovery_stripcharts. You should see something like the image to the right.
Line 26: Line 22:
 
** Mode 3 is CW
 
** Mode 3 is CW
  
[[File:Targetcontrol.png|thumb|upright=1.0|right|alt=Target motion control|Target motion control]]
 
 
* The last plot is the target ladder position in volts.
 
* The last plot is the target ladder position in volts.
 
** This readout matches the voltages displayed on the target motion control GUI.
 
** This readout matches the voltages displayed on the target motion control GUI.
Line 32: Line 27:
  
 
=== Harp scans ===
 
=== Harp scans ===
  '''Goals '''
+
==== Purpose ====
  - Verify operation of Harp scanners w/ beam.
+
* Verify operation of Harp scanners w/ beam.
  - Establish acceptable beam profile.  
+
* Establish acceptable beam profile.  
  
  '''Note'''
+
==== Note ====
  - We need sigma=100–500um at the target
+
* We need sigma=100–500um at the target
  - If sigma is larger than 500um, ask MCC to tune beam.
+
* If sigma is larger than 500um, ask MCC to tune beam.
  - Once sigma reaches below 500um, call RC for advice on whether we should accept the beam.
+
* Once sigma reaches below 500um, call RC for advice on whether we should accept the beam.
  
  '''Setup '''
+
==== Setup ====
  - Beam Current:  5 uA CW
+
* Beam Current:  5 uA CW
  - Target:        No Target  
+
* Target:        No Target  
  - Raster:        Off
+
* Raster:        Off
  
  '''Procedure'''
+
==== Procedure ====
  1) Verify that the raster is OFF
+
[[File:Aharpscan.png|thumb|upright=0.5|right|alt=Harp scans|Harp scans]]
  2) Ask MCC for harp scans with IHA3H07A and IHA3H07B
+
# Verify that the raster is OFF
  3) Verify beam profile:
+
# Ask MCC for harp scans with IHA3H07A and IHA3H07B
    i  ) Find the harp scans on the Ops ELOG. They should be titled "HarpFitter: IHA3H07A" and "HarpFitter: IHA3H07B"
+
# Verify beam profile:
    ii ) On a counting house desktop, run `harp_project_to_target`
+
## Find the harp scans on the Ops ELOG. They should be titled "HarpFitter: IHA3H07A" and "HarpFitter: IHA3H07B"
    iii) Enter the sigma values from peak 2 and peak 3 of both harp scans
+
## Open a terminal and run `harp_project_to_target`
    iv ) The script will project the width to the target and suggest an appropriate raster diameter to request from MCC
+
## Enter the sigma values from peak 2 and peak 3 of both harp scans
    v  ) Confirm with the RC that this value makes sense.
+
## The script will project the width to the target and suggest an appropriate raster diameter to request from MCC
 +
## Confirm with the RC that this value makes sense.
  
  If you'd like to verify the projection script's arithmetic, you can use the distances in Dave Gaskell's comment
 
  on this log entry.
 
  https://logbooks.jlab.org/entry/3764458
 
 
 
  The script's repository has a longer discussion of projecting the width from the harps to the target.
 
  https://github.com/johnmatter/harp_scan_projection
 
  
=== Initial Raster check with YAG Viewer===
+
* If you'd like to verify the projection script's arithmetic, you can use the distances in Dave Gaskell's comment on this log entry.
  '''Goals '''
+
** https://logbooks.jlab.org/entry/3764458
  - Establish beam to be roughly centered in beam pipe by locating it on [[Hall_C_YAG_Viewer |YAG viewer]] just upstream of target.
+
* The script's repository has a longer discussion of projecting the width from the harps to the target.
  - Turn on Raster and verify beam profile expands as expected.
+
** https://github.com/johnmatter/harp_scan_projection
  - No CW beam should be allowed in the Hall until this step is completed.
+
   
+
  '''Setup '''
+
  - Beam Current:   Tune Beam (Viewer limited)
+
  - Target:        No Target
+
  - Raster:        Off; 5mm diameter
+
  
  '''Procedure'''
+
=== Raster check with YAG Viewer===
  1) Call MCC to insert YAG viewer on Hall C superharp girder.
+
==== Purpose ====
  2) Start with raster off. MCC should post a picture. Verify the beam spot is roughly centered.
+
* Establish beam to be roughly centered in beam pipe by locating it on [[Hall_C_YAG_Viewer |YAG viewer]] just upstream of target.
  3) If the beam energy has changed, check that on the Hall C Raster Control GUI it is initialized for the correct beam energy.
+
* Turn on Raster and verify beam profile expands as expected.
  4) Request raster on with the diameter determined from the harp scans.
+
* No CW beam should be allowed in the Hall until this step is completed.
  5) 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.  
+
  6) 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
+
==== Setup ====
  - Another example posted in elog: https://logbooks.jlab.org/entry/3768480
+
* Beam Current:   Tune Beam (Viewer limited)
  - 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).
+
* 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 the beam spot is 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.
 +
# Request raster on with the diameter determined from the harp scans.
 +
# 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).
  
 
=== Check Beam Positions ===
 
=== Check Beam Positions ===
  '''Goal '''
+
==== Purpose ====
  - Do this if nominal beam positions are already established.
+
* Ensure that the beam positions are what we expect.
 +
* Do this if nominal beam positions are already established.
  
  '''Setup '''
+
==== Setup ====
  - Beam Current:  5 uA CW
+
* Beam Current:  5 uA CW
  - Target:        No Target
+
* Target:        No Target
  
  '''Procedure'''
+
==== Procedure ====
  1) With "No Target" position, ask MCC for 5uA CW and verify beam position with established nominal position
+
# With "No Target" position, ask MCC for 5uA CW and verify beam position with established nominal position
  2) In the orbit locks' "Expanded View" window, verify that the values in the light blue boxes match the nominal positions.
+
# Search for "orbit" in jmenu, and select "Orbit Locks Expanded View" from the drop down menu
 
+
# Find the row labeled "HallCOrb" (this box should be green!)
  If you can't find the orbit lock expanded view, do the following:
+
# Click the far right button labeled "Other", and select "HallCOrb Corrector and Bpm Info" from the drop down menu
  1) Search for "orbit" in jmenu, and select "Orbit Locks Expanded View" from the drop down menu
+
# Verify that the values in the light blue boxes match the nominal positions.
  2) Find the row labeled "HallCOrb" (this box should be green!)
+
  3) Click the far right button labeled "Other", and select "HallCOrb Corrector and Bpm Info" from the drop down menu
+
  4) Verify that the values in the light blue boxes match the nominal positions.
+
  
  As of January 26th, 2020, the positions should look like this log entry.
+
* As of January 26th, 2020, the positions should look like this log entry.
  https://logbooks.jlab.org/entry/3768504
+
https://logbooks.jlab.org/entry/3768504
  
=== Target/Beam centering, Raster checkout ===
+
=== Target/Beam centering, Raster checkout (optional) ===
  '''Goals '''
+
==== Purpose ====
  - Establish beam position on target, check/confirm raster size
+
* Establish beam position on target, check/confirm raster size
  - This step is optional, consult RC whether we need to do this.
+
* This step is optional, consult RC whether we need to do this.
  
  '''Procedure'''
+
==== Procedure ====
  - see https://hallcweb.jlab.org/wiki/index.php/Beam_and_Raster_Checkout_for_A1n/d2n_(Long_Procedure)#Target.2FBeam_centering.2C_Raster_checkout
+
* https://hallcweb.jlab.org/wiki/index.php/Beam_and_Raster_Checkout_for_A1n/d2n_(Long_Procedure)#Target.2FBeam_centering.2C_Raster_checkout

Revision as of 17:43, 26 January 2020

When should we do a short beam checkout?

  • After beam studies (typically on Tuesdays)
  • If for some reason the accelerator has been down for a "significant" period of time (say, more than ~8 hours)
  • If anything "significant" has changed in the beam line and you are not sure if it will affect the position or profile of the beam delivered to the hall

Procedure

Beam restoration stripcharts
Beam restoration stripcharts
Target motion control
Target motion control

Open Stripcharts

  • You should monitor the beam position, mode, and current during this process.
  • Open a terminal and run go_beam_recovery_stripcharts. You should see something like the image to the right.
  • The first set of 4 charts are the field integrals of the orbit lock corrector magnets.
    • If they are operating properly, you should see the value changing when the beam is on. This means they are properly keeping the beam in the position we want.
    • These will flatline when the beam trips. This is normal behavior.
  • The second set of charts are beam positions at harps 3H07A and 3H07C. These positions (set by the corrector magnets) should match the nominal values on the wall screen.
  • The third set of charts are BCM current and Hall C beam mode, which indicates what type of beam MCC is sending. You should monitor both.
    • Mode 2 is tune beam (beam with a 1.5% duty factor used when first checking the orbit and sending beam to the hall).
    • Mode 3 is CW
  • The last plot is the target ladder position in volts.
    • This readout matches the voltages displayed on the target motion control GUI.
    • The two values shown here, 7.88V and 7.11V, correspond to No Target and Pol He3 Cell respectively.

Harp scans

Purpose

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

Note

  • We need sigma=100–500um at the target
  • If sigma is larger than 500um, ask MCC to tune beam.
  • Once sigma reaches below 500um, call RC for advice on whether we should accept the beam.

Setup

  • Beam Current: 5 uA CW
  • Target: No Target
  • Raster: Off

Procedure

Harp scans
Harp scans
  1. Verify that the raster is OFF
  2. Ask MCC for harp scans with IHA3H07A and IHA3H07B
  3. Verify beam profile:
    1. Find the harp scans on the Ops ELOG. They should be titled "HarpFitter: IHA3H07A" and "HarpFitter: IHA3H07B"
    2. Open a terminal and run `harp_project_to_target`
    3. Enter the sigma values from peak 2 and peak 3 of both harp scans
    4. The script will project the width to the target and suggest an appropriate raster diameter to request from MCC
    5. Confirm with the RC that this value makes sense.


Raster check with YAG Viewer

Purpose

  • 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.
  • No CW beam should be allowed in the Hall until this step is completed.

Setup

  • Beam Current: Tune Beam (Viewer limited)
  • Target: No Target
  • Raster: Off; 5mm diameter

Procedure

  1. Call MCC to insert YAG viewer on Hall C superharp girder.
  2. Start with raster off. MCC should post a picture. Verify the beam spot is roughly centered.
  3. If the beam energy has changed, check that on the Hall C Raster Control GUI it is initialized for the correct beam energy.
  4. Request raster on with the diameter determined from the harp scans.
  5. 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.
  6. MCC will retract viewer after check is done.


Check Beam Positions

Purpose

  • Ensure that the beam positions are what we expect.
  • Do this if nominal beam positions are already established.

Setup

  • Beam Current: 5 uA CW
  • Target: No Target

Procedure

  1. With "No Target" position, ask MCC for 5uA CW and verify beam position with established nominal position
  2. Search for "orbit" in jmenu, and select "Orbit Locks Expanded View" from the drop down menu
  3. Find the row labeled "HallCOrb" (this box should be green!)
  4. Click the far right button labeled "Other", and select "HallCOrb Corrector and Bpm Info" from the drop down menu
  5. Verify that the values in the light blue boxes match the nominal positions.
  • As of January 26th, 2020, the positions should look like this log entry.

https://logbooks.jlab.org/entry/3768504

Target/Beam centering, Raster checkout (optional)

Purpose

  • Establish beam position on target, check/confirm raster size
  • This step is optional, consult RC whether we need to do this.

Procedure