Changes between Version 4 and Version 5 of Research/LhARA/RadiationBiology/Meetings/2026-02-24


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Timestamp:
Mar 2, 2026, 2:51:24 PM (3 months ago)
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ccd24
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  • Research/LhARA/RadiationBiology/Meetings/2026-02-24

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    99==== Radiobiology Results ====
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     11[raw-attachment:"EMelia LhARA 240226.pptx​​" Slides]
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    1013The aim going into the experiment was to get the first results towards reproducing the survival curves seen using Birmingham's MC40.
    1114Phase 2 used post-plating, which allows for more statistics and provides better survival than pre-plating. Due to previous controls, a lack of survival, 1mm of media was added to the cell dish, which improved survival.
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    2629==== RCF Analysis ====
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     31[raw-attachment:Phase2_RCF_Analysis.pptx Slides]
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    2733The RCF was collected in two types. 20 in 5cm square pieces and 30 in 1.5cm square pieces. The aim was to characterise the shot-to-shot variation and the spatial variation to give an uncertainty on each dose delivered. By assuming that the shot-to-shot variation was normally distributed and performing a maximum likelihood fit on the mean dose and the shot-to-shot uncertainty, we calculated the mean dose to be 0.57Gy with a shot-to-shot variation of 0.40Gy. The reduced chi-squared of the fit is 1.05. The coefficient of variation was 13.93% ± 1.79% and showed no obvious dependence on the dose delivered. This meant that for the relevant shot counts, (4,7,14), the predicted dose was 2.28±0.87Gy, 3.98±1.21Gy and 7.97±1.87Gy. There were also 8 pieces of RCF collected when the Cu scatterer was moved closer to the laser target. This reduced the median CV from 14.06% to 7.88%. This is still not low enough to be completely satisfactory, but much closer. It also means that we delivered around half the dose per shot.
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    2935
    3036=== SCAPA Beamline Analysis ===
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     38[raw-attachment:"PoPlaR_In_Person_Meeting_24Feb_2026_v1_RW 1.pptx​" Slides]
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    3240We have completed the allocated days currently at SCAPA. Currently, 4 types of beamline end that can be installed:
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    4856
    4957==== Sparse Scintillating-Fibre Array ====
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     59[raw-attachment:LhARA_24Feb26.pdf​ Slides]
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    5161Calvin has simulated the expected energy deposition in an individual fibre. It appears that many fibres will potentially be saturated, obviously depending on their position in the beamline. Generally, we want to avoid placing any electronics within the vacuum chamber as the EMP from the laser-target interaction will likely knock these out. Therefore, Peter discussed different methods of transporting the light outside of the chamber. Peter has simulated one fibre with a Polystyrene (Core) and PMMA (cladding) as per BCF20. He has tested using another fibre of wider diameter to transport it out, as well as using lenses to transport the light. The fibre transport 7% of the light while the use of two paraxial lenses transports 4.6%. The lateral, angular and longitudinal offsets of the transporting fibre were all tested for their sensitivity. The transport was most sensitive to the longitudinal offset. The next step is to consider how to transport the light from multiple fibres out of the chamber.
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    109119==== Future Beamlines ====
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     121[raw-attachment:PoPLaR_collab_meeting_24Feb26.pdf​ Slides]
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    110123Josie has completed several simulations varying the number of PMQs and the drifts between the beamline elements. Using Bayesian optimisation and with the restriction that the minimum drift to the first PMQ and the minimum drift between PMQs is 93mm, the best result was in a 2 PMQ setup. Currently running a Bayesian optimisation that releases all the constraints to find the best setup, whether physically feasible or not. We can then probe the restraints that need to be broken to see how flexible they are.
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