Detailed Steps for Tuning In-Flight Beams
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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.
- Acquire information on primary/degraded beam tunes and prep for beam
- Get docs from operations on primary and degraded beam TOFs and the charge state and slit scan data
- Acquire the final cup/collimator FC currents and any notes on degraded beam transmission
- Note down RAISOR slit settings (in particular the midplane vertical slits are key)
- Insert detector of choice, make sure HV and preamps are on and daq is alive w/ noise etc
- Get a reference spectrum from the degraded beam (can be done at RAISOR exit or target depending)
- Cut back beam by x100 w/ slits (not RAISOR slits) first then insert all available attenuation (~x15 Million)
- Place beam on detectors and slowly remove attenuation until rates are roughly >100 Hz & <500 Hz
- Take ref spectrum - optimize daq params and save the settings file as they should not be changed for the duration of the run
- Determine the RF Sweeper phase for full or largest degraded beam removal
- Set degraded beam rate to few hundred Hz and get Grafana running
- Have operations turn on Sweeper to Voltage=2 and phase=0 to start
- Note: You already may see a reduction in the beam rate do not increase beam current to get back to few hundred Hz
- Scan the RF Sweeper Phase in 5 degree steps, noting on Grafana or elsewhere, what angle the beam rate is a minimum
- Do smaller steps of ~1 degreed around the regions of the minimum to try and get the best angle
- TURN OFF THE SWEEPER FOR NOW (or maybe only needs to have V=0)
- Should be back to the few hundred Hz rate as at the beginning
- Identify the secondary beam
- Incrementally scale the RAISOR / beam line magnets in 0.5-1% steps until 1% or so past expected scale value
- At each step, remove attenuation to achieve the 100-500 Hz rates and searching for the beam of interest
- 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).
- Generate cuts at each step to track the movement of the beam charge states etc.
- Identify the isotope of interest based on calculated energies or previous production of the isotope
- Calculate the rate of the isotope of interest as the pps / pnA [note: pnA value from FCA001 divided by q of primary beam]
- Optimize and transmit secondary beam
- Once beam is on peak scale factor, make sure operators have access to direct rate of secondary beam either via grafana
- Operators should optimize tune at desired location
- Repeat steps above at target station if first carried out at RAISOR exit
Definitions
- 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