Proton Calorimetry/Future Work

Personnel

• UCL: Simon Jolly (SJ), Joseph Bateman (JB), Febian (F), Matt Warren (MW), Harry Barnett (HB).
• Bari (Ba): Raffaella Radogna (RR).
• Oxford University (Ox): Pete Hastings (PH), Mark Jones (MJ).
• Imperial College (IC): Andy Rose (AR), Duncan Parker (DP), Munir Saleh (MS).
• Heidelberg (He): Blake Leverington (BL), Julian Horn (JH).

Design Goals

• Real-time measurements of PBT beam range with sub-millimetre precision using plastic scintillator range telescope.
• Real-time measurement of PBT beam spot size/position with sub-millimetre precision using scintillating fibre arrays.
• Coverage of “clinically relevant” transverse scanning area and range:
  • 250 MeV/400 mm range.
  • 5 cm × 5 cm scanning area.
• Integration into single portable detector enclosure with single power and network inputs and nozzle mount.
• Full system control and display with web-based GUI from on-board DAQ.

Current Status (October 2025)

• QuARC tested in Trento:
  • Calibration stable.
  • Range measurements repeatable.
  • Full GUI control.
• Fibre array prototype tested in Trento:
  • Analogue Hamamatsu photodiode arrays and driver circuits.
  • NI-driven DAQ.
  • Fibre arrays assembled in Italy with 500 micron scintillating fibres.
  • Repeatable, low noise measurements of beam position and profile at multiple positions and sizes.

QuARC Development

• Reduce scintillator sheet thickness/photodiode spacing to 2.5 mm.
• Improve manufacturing process and surface finish.
• Move from 2 to 4-sided photodiode readout.
• Replace individual photodiodes with 16-element arrays.
• Daisy-chain electronics around 4 sides of single module.
• Increase scintillator area to 150 × 150 mm.

Scintillator Development

• Existing scintillator sheets need machining on Datron to improve quality and reduce thickness to 2.5 mm: HB.
• Superior quality scintillator blanks needed from Nuvia: HB and SJ to liaise with Hana Buresova.
• Move to larger area scintillator sheets once 100 mm sheet production refined.

Scintillator Modules

• Redesign scintillator stack holders for 4-sided readout: HB.
• Individual modules must be self-contained and pre-cabled on 3 sides with only top-mounted USB-C I/O connector needing to be connected when assembling.

Photodiodes and Electronics

• Front-end DDC boards need to shrink to accommodate Hamamatsu S12362 16-element arrays with 2.5 mm pitch: PH.
• Replace vertical USB-C connectors with horizontal and move to upstream end to match new 4-sided setup: PH to liaise with HB.

DAQ and GUI

• Streamline existing FPGA code to improve memory management: MW.
• Replace Raspberry Pi/USB104 with QuADProBe Kria (see below): F.
• Live GUI frequently unresponsive, needs resolving: JB.
• Replace PapaParse with direct JSON input: JB.
• Ensure post processing and replay fully functional to review previous beam tests: JB.

QuADProBe Development

• 250 micron square scintillating fibre arrays: RR.
• Hamamatsu digital S17285 photodiode array readout.
• Kria-based DAQ.

Front-End Electronics

• Move to Hamamatsu S17285 arrays.
• Mechanical design of holder for scintillating fibres and photodiode arrays: HB.
• Interface board needed for power/timing signal distribution and board I/O: PH.

DAQ

• Transition from Pi/USB104 to Kria.
• Kria needs bespoke carrier board for power and DAQ interconnects: IC.
• Port existing Pi DAQ code to Kria: F.
• Expand firmware to include SciFi readout and 4-sided QuARC: F.
• Modify GUI to include spot position measurements: JB.

Reconstruction

• Development “Event Tagging” system to sync SciFi and QuARC “Events”: JB.
• Streamline reconstruction process to allow rapid reconstruction of acquired data: JB.

Mechanical Design (HB)

• Enlarge cover/alignment plates and resolve offset.
• Investigate use of carbon fibre sheet to replace aluminised mylar windows.
• Modify rails with better mounts for module fixation.
• Nozzle mount.

Calibration and data

• Is it possible to calibrate the detector without a proton beam?
• Maybe an e- beam beta source?

Future Beam Tests

• Compare QuADProBe performance against HIT scintillating fibre array: SJ to liaise with JH.
• Retest alignment of Czech PTC nozzle and QA: SJ to liaise with Prague PTC.
• Collate list of centres that can provide scanned fields/treatment plans from experimental nozzles: SJ.
• Nozzle-mounted test with Mevion system at Maastro.