Detailed Steps for Tuning In-Flight Beams

From ATLAS Accelerator In-Flight Beam Program
Revision as of 18:20, July 21, 2021 by Crhoffman (talk | contribs)
Jump to navigation Jump to search

Overview of the steps for In-flight beam delivery

Once steps for degraded beam tuning have been completed and a good focus is found at the RAISOR midplane (Separate detailed sheet for this), the steps below can be used to help guide the identification and tuning of the secondary beam.

  1. Acquire information on primary/degraded beam tunes and prep for beam
    1. Ask for docs from operations on primary and degraded beam TOFs and the charge state and slit scan data to be loaded into BOX
    2. Acquire the final cup/collimator FC currents and any notes on degraded beam transmission
    3. Note down RAISOR slit settings (in particular the midplane vertical slits are key)
    4. Insert detector of choice, make sure HV and preamps are on and daq is alive w/ noise etc
  1. Getting a reference spectrum from the degraded beam (can be done at RAISOR exit or target depending)
    1. Cut back beam by x100 w/ slits (not RAISOR slits) first then insert all available attenuation (~x15 Million) + RAISOR Att if needed
    2. Place beam on detectors and slowly remove attenuation until rates are roughly >100 Hz & <500 Hz
    3. Take ref spectrum - optimize daq params and save the settings file as they should not be changed for the duration of the run
    4. Run the RAISOR midplane slits in to 2 - 3 mm gap and take another spectrum (better to have small slit spacing for BRho scans)
  1. Determine the RF Sweeper(R501)/R401 phases for degraded beam with known TOF
    1. Set degraded beam rate to few hundred Hz and get Grafana running
    2. Have operations turn on Sweeper to Voltage=2 and phase=0 to start (R401 is still off)
      1. Note: You already may see a reduction in the beam rate do not increase beam current to get back to few hundred Hz
    3. Set the increment step = 1 degree, operators hold down increment to scan over 360 noting the phase every 10 - 20 degree
    4. Document the phase that transmission is the highest
    5. Do smaller steps of ~1 degreed around the regions of the maxima (should be two that are similar one <180 one >180 deg)
    6. Leave Sweeper(R501) at optimal phase, increase amplitude to 3,4,5,6V to see if improvement in transmission, note the best value.
    7. Set Sweeper (R501) to optimal phase/amplitude
    8. Turn on R401 to phase = 0, amp ~ 1.1 or 1.2 (below 0.9 seems to give it issues locking up)
    9. First scan phase, then scan amplitude similar to Sweeper to find optimal R401 parameters, note the values.
    10. TURN OFF THE SWEEPER AND R401 FOR NOW (or maybe only needs to have V=0??)
    11. Should be back to the few hundred Hz rate as at the beginning
  1. Identify the secondary beam
    1. Incrementally scale the RAISOR / beam line magnets in 0.5-1% steps until 1% or so past expected scale value
    2. At each step, remove attenuation to achieve the 100-500 Hz rates and searching for the beam of interest
    3. Take a fixed time run with the daq to note rates / purities (Compass and Ryan's boxscore separately would be good to cross check things if needed).
    4. Generate cuts at each step to track the movement of the beam charge states etc.
    5. Identify the isotope of interest based on calculated energies or previous production of the isotope
    6. Calculate the rate of the isotope of interest as the pps / pnA [note: pnA value from FCA001 divided by q of primary beam]
  1. Optimize and transmit secondary beam
    1. Once beam is on peak scale factor, make sure operators have access to direct rate of secondary beam either via grafana
    2. Operators should optimize tune at desired location
    3. Repeat steps above at target station if first carried out at RAISOR exit


  • primary beam - the beam species and charge state taken out of the source at the ATLAS energy requested
  • degraded beam - the same beam species as the primary beam but at a different (lower) energy and most likely different (higher) charge state
  • production target - the target put in place before RAISOR, e.g., Be foil or Gas Cell