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:
  • 230 MeV/330 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.

Scintillators and PD

• Scintillators uniform in thickness (3mm) and flatness.
• Machine block clear polished sheets.
• For 245 MeV, is it doable to do 1 module of 32 PD with the 2.8mm thick and then 3 modules of 32 PD with scintillators 3mm thick?
• For low energy just 1 module of 2.8mm
• Photodiodes are OK, there are no issues in the coupling.

DAQ & Electronics

Redesign of the analog circuit. The boards need a revision.

• We want everything to connect via usb-C (currently there is only one usb-C cable that does not work properly and it is a very long one). Did Saad discuss this with Marco? What was the outcome of the lab tests?
• We need all the power to come just from FPGA (5V, ~2A) ➾ the voltage regulator chips need to go.
• Long usb-C between the daugther board and the DDC will be removed, and the two can connect directly [daughter board - bridge usb C board - (usb C cable) - bridge board - DDC board]
• FPGA from Saad had some glitches that need to be resolved. Do we see those with Nexus as well as the usb104? ➾ On board fitting needs to be implemented

Calibration and data

Is it possible to calibrate the detector without a proton beam?

• Maybe an e- beam beta source?
• Modify the geant4 simulation to verify what E will we need so there is no quenching?
• Can we obtain average results to mitigate position sensitivity?

GUI

• Implement any options needed that have user input
• Replay and post-processing options
• Version with full live detector control ➾ reset and relaunch options included
• Check current varian control system: what does if offer and how do they control the detector? ➾ Check with Clatterbridge, Allison and A. Mazal

Mechanical design

• For 245 MeV, is it doable to do 1 module of 32 PD with the 2.8mm thick and then 3 modules of 32 PD with scintillators 3mm thick?
• How can we design the modules so they can attach and detach easily? ➾ We need a robust design but not rigid
• Power distribution?
• Beam windows? Light tight?

Future beam tests

• Beam test where we check the shape and position of the BP (scanning field)
• Real treatment plans
• Testing with real gantry mount