LhARA radiobiology; meeting: 05Mar26; 14:00 GMT

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

Attended: PH, KL, JB, MH, CW, ND, AFr

Meeting Notes

0. Short Recap of In-Person

1. BioPrep

• Updates:
  • No Update but things discussed:
    • Short-term plan is probably use Marie's lab as it has the microscope, etc., but there is a preference to shift to doing everything at SCAPA.
    • Monitoring for the incubator, Robbie can do remote monitoring for the incubator using a Raspberry Pi, etc.
    • Would be useful to find the hard limit that cells can survive vertically

Something has been a problem with burning mirrors that was there before with Ross

2. Simulations

• Updates:
  • Josie presented the latest BO results on finding the optimal beamline
    • Slides
    • Ran several optimisations, all using a laser-driven energy spectrum:
      • 2 Quad (Varying positions for transmission)
      • 2 Quad (Varying positions for uniformity)
      • 2 Quad and 4 Dipoles (Varying positions and varying dipole length and strength as a group for transmission)
      • Any Quad Combination (Varying number and position of quads for transmission
    • Generally, best results appear to have the beamline elements as close as possible to the source and have the cells as close as possible too.
    • To get a more useful optimisation need to specify a beam energy
      • Talk to Robbie about the energy spectra graph and its stability
      • Talk to the bio team about what energies we should be avoiding (Simulate LET for a range of energies in the cells?)
  • BELLA Paper
    • Deliver a 2.0 ± 0.4Gy beam with a lateral dose variation of 7% and centred on 8MeV
    • The average uncertainty on their overall dose delivered was 12%
    • Beamline consists of a laser-driven source, quad doublet, kapton scattering foil, dipole magnet, mouse ear, RCF and scintillator
      • Laser-driven source ran at 7J over 60fs, so lower power than SCAPA, and onto a 13um Kapton target (same as SCAPA).
        • The laser was 50um from its optimal focal length to achieve a better shot-to-shot variation. This helped reduce it from 17% to 5%
      • Quads are a 250 T/m with 5mm bore radius and 67T/m with 15mm bore radius
      • Kapton scattering foil is 25um and is placed there to smooth the beam and remove heavier ions
      • Dipole magnet of 264mT and 95mm in length removes x-rays, gamma-rays and electrons
      • 25um Kapton exit window
      • The mouse ear is ~300um so it allows 8MeV protons to pass through and reach RCF and a scintillator passed that
      • Other diagnostics are integrating current transformers
        • Would be worth investigating in combination with sci-fi arrays for instantaneous dose measurements
    • They delivered a shot every 20s, so they investigated instantaneous FLASH rather than overall FLASH
    • Josie will simulate the beam to get a better understanding
      • LhARA knows someone at BELLA, so she is the person to ask if any information is missing

3. SCAPA Beamline

• Updates:
  • No update, but things discussed:
    • Is there something that can stop the lens element from burning? Maybe something that Ross used to use?

4. In-Beam Diagnostic

• Updates:
  • No update, but things discussed:
  • Jeff mentioned putting cells on RCF
    • ​https://pmc.ncbi.nlm.nih.gov/articles/PMC12340475/#:~:text=5.,delivered%20to%20the%20cell%20substrate.

5. Other beamlines

• Updates:
  • Josie is sourcing the information to simulate ELI
    • Nick suggested emailing since they are usually happy enough to share information
  • There is a space to apply for beamtime at ELI
    • Deadline is 22nd Apr

6. DoNM
   • 19th Mar 14:00

7. AoB

Summary of actions required

In-Beam Diagnostics

• RW, CD: Study correlation between laser diagnostics and mean dose
• CD, TP: Refine evaluations of LET in the cells with the RCF in front
• CD: Predict the cell dish dose from the RCF in front of it
• PH: Investigate how to get the light out of the vacuum chamber
• Investigate how a phosphor sheet could be incorporated into the design
• Acquire a glass sheet

Bio Next Steps

• EM: Write up a biology plan
  • Decide whether to use Marie's lab and whether to stick with HeLa
• EM, MB, JP, RA: Meet to finalise details
• Unassigned: Obtain an inverted microscope
• Unassigned: Run controls to examine how long the cells can survive vertically

Improve the spatial variation

• Decide the energy we should be optimising for
  • RW: Examine energy spectra variation
  • Find LET for different energies in the cell dish

Other Beamlines

• JMcG: Simulate BELLA
• JMcG: Talk to ELI people and simulate ELI
• Build a bid towards ELI

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