Minutes for UCL Proton Calorimetry Meeting, 22nd November 2017 (D17, Physics & Astronomy, UCL)
Simon Jolly, Ruben Saakyan, Laurent Kelleter, Anastasia Basharina-Freshville, Jordan Silverman, Dan Walker, Matthieu Hentz
- Fitting finally seems to work for single module spectrum:
- Landau-Gaussian convolution with second degree polynomial.
- ROOT requires specific order: fits Landau-Gaussian first.
- Small features on the left of peak show extra 'wrinkle' which is not quite fitted; not present in July'15 data with UCL negative base.
- Fit worse for MedAustron data but likely to be a result of pile-up.
- FWHM from fit overestimates resolution slightly.
- Hamamatsu provided quote for flat panel detectors:
- Contact person Simon Whitehead.
- Recommended C9730DK-10 with faster readout rate but larger noise.
- Will ask for quote for C9728SK-10 and check which has larger dynamic range.
- Will also check whether we can get demo model to test: full cost £16k + £2k for software.
- Working on staged simulation to improve speed:
- Large speed difference between good and bad nodes: trying to script finding fastest nodes...
- Time limit of 12 hours for medium queue: some jobs overrun due to slow nodes and get ejected.
- Also trying to visualise beam profile every 25mm:
- Can't define overlapping geometries: need to include parallel world with sensitive detectors.
- No response from Ben Morgan: will email Geant4 mailing list.
- Sensitive detectors provide speed up over writing data in the stepping action.
- Will look into getting Oyster cards for ENLIGHT meeting delegates.
- Visit to Nuvia Monday/Tuesday:
- Requested 100x100mm sheets, 2mm or 3mm thick depending on reliability of production.
- Total thickness of 60mm
- Nuvia produce a thick piece of scintillator, then squeeze under heat to correct thickness, then cut out sheet.
- Previous issues result from lack of attention to pressing...
- Samples will arrive before Christmas (perhaps not all...).
- Hana about to go away on maternity leave...
- Should be possible to cut and polish samples before they arrive:
- Derek can cut some pieces from existing spares.
- Georgio Savini and David Brooks should have expertise on polishing.
- Nuvia may be able to polish themselves.
- ROOT scripts for reading Lecroy binary files is now working.
- Defines classes for acquiring and manipulating data.
- Just got histogram spectrum working.
- Will reject bad pulses and pulses with high variation in baseline.
- Can output data to suitable file format.
- Working on alternate fit for single module spectrum:
- Fit uses Landau-Gaussian convolution with extra exponential part.
- Χ2 per NDF above 5.
- Not entirely dissimilar from Anastasia's fitting function...
- Will review in a week.
- All of last few weeks spent writing paper on Build-Up Effects in Proton Therapy:
- Struggling to define protonic build-up in robust way.
- Using 30% of Bragg peak good at high energy but poor at low energy.
- Bortfeld formula works in opposite direction: would rather not use fit (need to check with Adam Gibson).
- Have contacted Tracey Underwood to review paper.