Multi-colour sctintillator-based ion beam profiler James Green, Oliver Ettlinger, David Neely (CLF / STFC) 2 nd Ion diagnostic workshop June 7-8 th

Talk outline Diagnostic outline Multi-channel characterisation Reducing EMP & radiation effects Demonstration on Astra Gemini Future developments

High-repetition rate advances Passive media (CR-39, RCF, Image plate) increasing unsuitable Transition to active diagnostics: Scintillators, Micro-channel plates (MCPs), Phosphor screens Target Laser CCD Fibre bundle Scintillators Lens Ion beam Micro-channel plates (MCP) Radiochromic film (RCF)

2D detector head development Diagnostic aims: – 2D beam profiling – Spectral measurement – Beam pointing – Calorimetry Compact scintillator beam head – Scintillator thickness determines energy observation window – Each scintillator has a separate central emission wavelength – Need to avoid optical excitation within scintillator stack Scintillator 3 (Blue) Scintillator 1 (Orange Scintillator 2 (Green) Incident Protons 100 mm 90 mm Detector head Proton stopping ranges

Optical Stimulation Optical Stimulation: – Emission from Blue or Green scintillators can optically stimulate emission from scintillators earlier in the stack – How to stop light travelling back through the system? 5 Scintillator 3 (Blue) Scintillator 1 (Orange Scintillator 2 (Green) Incident Protons

Reducing EMP / radiation impact High resolution 800 x 800 fibre bundles – Image relay from Phosphor / Scintillator to camera outside interaction chamber – Durable with flexible deployment options – Wide transmission range – Long fibre lengths (> 5 m) possible Eliminating background radiation – Gated CCDs to block X-ray / electron signal – CCD safely shielded from hard hits 60um CoreCore Optical Cladding Optical Core Groups of fibres inside bundle

Channel separation Signal split in front of camera into 4 channels, RGB + Extra Dichroic filters used to isolate each scintillator signal RedGreen BlueAll channels Data obtained using from SRIM –

Data Deconvolution System characterised using a Cyclotron proton source Produced a response matrix for each colour channel 8 Predicted Response Matrix -Ideally require 1 on the diagonal, with 0 everywhere else

Astra Gemini experiment Astra Gemini – – 12J 50fs – 5x10 20 Wcm -2 – >10 10 contrast – TCC – Scintillator = 20 cm Scintillator 3 (Blue) Scintillator 1 (Orange Scintillator 2 (Green) Incident Protons MeV 7-9 MeV MeV Laser

Astra Gemini experiment MeV7-9 MeV MeV 50 nm Al Shot a range of Al foils, nm Clear signals on orange and green channels, insufficient flux for blue Clear structure visible with peak off axis for some shots FOV = 30 o 100 nm Al

Imaging novel targetry Microspoke targets shot on Astra Gemini Proton beam imaged using RCF and Scintillator stack 11 1mm Disks: 32um diameter, 40nm thick SiN membranes Supporting wires: 1µm wide, 40 nm thick Hole etched through 400μm thick Si. Scintillator RCF

10 Hz operation Scintillator considerations: – Rapid (  s) recovery between shots – Minimising high dose damage Implement new Scientific CMOS camera – 30 fps continuous full-frame operation – Low noise read-out, 16-bit Dynamic range Data analysis – Real-time data deconvolution for live beam profiles (Desirable – looking for collaborators?)

Future developments Further diagnostic testing – 0.05 Hz to 10 Hz progression – Efficient data capture and analysis Scintillator development – Thin scintillators for high spectral resolution – Calibration at higher (> 30 MeV energies) – Faster scintillators for fast gating – Media lifetime Experimental & industrial collaborations – Experimental access on range of facilities – Next-gen imaging and scintillator technology