Detailed Steps for Tuning In-Flight Beams

From ATLAS Accelerator In-Flight Beam Program
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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. Get docs from operations on primary and degraded beam TOFs and the charge state and slit scan data
    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. Get 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)
    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
  1. Determine the RF Sweeper phase for full or largest degraded beam removal
    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
    3. Note: You already may see a reduction in the beam rate do not increase beam current to get back to few hundred Hz
    4. Scan the RF Sweeper Phase in 5 degree steps, noting on Grafana or elsewhere, what angle the beam rate is a minimum
    5. Do smaller steps of ~1 degreed around the regions of the minimum to try and get the best angle
    6. TURN OFF THE SWEEPER FOR NOW (or maybe only needs to have V=0)
    7. 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