LhARA radiobiology; meeting: 13Nov25; 14:00 BST

ZOOM: ​https://imperial-ac-uk.zoom.us/j/98220889714?pwd=SM90vOF7BKSXoU3mD9q7OwBQo4IVB3.1

Attended: EM, CD, JMcG, DA, TP, ND, MH

Meeting Notes

1. Minutes and actions:

• CW: Contact Marie Boyd
  • Done Waiting. Probably worth waiting till we irradiate cells.

2. Strathclyde: BT, ED, RW, CD, TP, EM
   

• RW: Update on laser
  • Front quad is quite shiny so placed something in front to reduce reflection.
  • Changed around 5 separate things and now (fingers crossed) do not see the burning...
  • Ran 20 shots on Tues and Weds and saw no burning
  • Does mean not sure what caused it and could be any of the 5 things, including front quad being reflective...

• CD: Recap of experimental and simulated results
  • Slides
  • Nick pointed out there is still a flaw in the comparison based on the number of particles reaching the final dish
  • Simulations producing similar shapes to experimental results
  • Based on Highland equation for multiple scattering angle (from Geant4 documentation) predicted the different scattering effects
  • Mark has offered 2.5um Gold if we wanted to try that?
  • Cu 10um at furthest distance from second quad seems like a sensible option
  • If not uniform enough can move it closer
  • If we move it so the copper is 300mm from second quad then sims predict the dose will drop by 45% and the CV goes down by 6%
  • Robbie has a spare drive that we could use to play with this without pumping down the vacuum chamber each time

• RCF update: Plan to recalibrate
  • EM update on Birmingham calibration
    • Calibration Done - Slides
    • 2023 batch is much preferred due to the framing we see around the edge of the darker batch
    • If we use the darker batch in the future cut only for the centre to avoid the framing
    • Calibration was also complete for some of the framed parts of the film to get some values for previously scanned work
    • Three sheets of the 2023 batch with Emma
    • I think there is more in SCAPA - Ask Ewan
  • KL/CD update on 2023 getting cut to 1cmx1cm:
    • Hopefully done by tomorrow
  • For future use best to buy a new batch and complete a calibration just before irradiating
  • Scanner Best Practices:
    • Place black cardboard around the RCF on the scanner to fix its position
    • Run 5-10 scans before scanning RCF to allow the scanner lamp to warm up
  • RCF Dose Calculation:
    • Slides
    • Key Conclusions:
      • Scanner Best Practices:
        • Place black cardboard around the RCF on the scanner to fix its position
        • Run 5-10 scans before scanning RCF to allow the scanner lamp to warm up
      • An x by x median filter kernel should be applied to the dose map before calculating the flatness. Tony uses x=5.
      • A three channel correction could provide a more accurate dose than using one channel
      • Variability pixel to pixel? - Comes from the scanner resolution and is not indicative of low stats hitting each cell
        • 1 Gy means around 70 particles traversing the nucleus

3. BioPrep EM, JP:
   

• EM: Dry run outcome
  • Staining to be completed on Monday
• CW: Marie Boyd update
  • Wait till we have some cells irradiated
• Emma has to be in Oxford on Friday so cells need to be irradiated before then
• Possibility of extra days due to laser downtime? - Chat more about this on Monday

4. Simulation CD, DA, AFr:
   

• No update other than sims included above

5. Beam Diagnostics KL, CD:
   

• Real-time beam diagnostic update
  • Lanex tested in the beamline appears to work
  • Lanex behind the cell dish

6. DoNM

• 27th Nov

7. AoB

• Josie viva - Completed it mate

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