Beam instrumentation using Coherent Cherenkov Diffraction Pyramidal cone

Beam instrumentation using Coherent Cherenkov Diffraction Pyramidal cone in Teflon Measuring in 3 bands (60 -90 -110 GHz) Simulation with Vsim Bunch length monitor Bunch position monitor

Next tests on CLEAR for Diagnostics • Add. Measurements : • Directivity of the radiation • Polarisation distribution of the radiation • Spectrum of the radiation • Measuring at 60 -90 -110 -200 GHz • We did not measure anything at 10 GHz when we tried the metamaterial target • Detection problem or limitation from the target design • How much power do we produce at longer wavelength 10 -30 GHz • Material studies • Replacing Teflon by Alumina / Quartz / Silicon … depending on bunch spectrum • Improved design • Mechanical design : ‘Towards an In-vacuum design’ • Larger aperture system compatible with realistic beam line (from 1 cm to 4 cm aperture) • Detection system (targeting a real application : AWAKE e- BPM ? ) • Avoiding in-air detection – in-waveguide detection scheme avoiding background sources • Optimized electronic detection system • Coupling to RF hybrid providing Delta and Sum signal for BPM applications

Next tests on CLEAR from long CCR targets • Producing the highest output power from Coherent Cherenkov radiation • Do we understand the power we produce with the long conical targets: • Two types : twice in length – twice in diameter – different diameter (maybe retrying with same diameter) • How can we produce more • Smaller aperture ? • Different material ? • Different shape ? • Measuring wakefield induced beam kicks from a long CCR • Tests in vacuum • Need to find another location on CLEAR : e. g. plasma lens or CLIC structure ? • Measuring beam kicks for different tilt angles and offsets in the radiator • Relevant for theoretical consideration and cooling/heating effects

Another test on CLEAR for THz production • Coherent Smith-Purcell • 2 D gratings • 3 D gratings, i. e. grating with sidewalls

Publications strategy (1/2) • Non-invasive beam instrumentation using coherent Cherenkov diffraction radiation • Introduction • Best (non invasive, simpler, more intense, less noise) diagnostic based on Coherent radiation • Bunch Length and beam position measurements • Measurements at CLEAR • Bunch length with comparison RF deflector • Beam position • Simulations using Vsim • Simulations larger aperture • Better design for BPM (@longer wavelength) • Better design for BLM • Novelty : known physic phenomena but new applications for beam instrumentation • Innovation : Compactness / Signal quality / • Applications for short bunches : PWFA / LWFA / DWA / DLA / FEL / Light source / • no energy limitation (accelerators) – very low energy, i. e. electron microscope Journal : Trying PRX - PRA ?

Publications strategy (2/2) • On the shadowing effect between two sources of Coherent radiation emitted by short bunches • Introduction • • • Generation of THz radiation and DWA Analogy and difference with shadowing effect at shorter wavelength explained well by interferences theory Analogy with the suppression of CSR using small aperture beam pipes • Test-bench for Shadowing / Interference studies at sub-THz wavelength using coherent radiation at CLEAR • • CDR/CTR • Metal / Metal (10 mm aperture) • Metal / Si (10 mm aperture) • Metal / Teflon thin (10 mm aperture) (without the emission of Cherenkov radiation) CCR/CTR • Metal / Teflon long target (10 mm aperture) (with the emission of Cherenkov radiation but no interference) : field clipping - no radiation • Metal / Teflon conical target (10 mm aperture) (with the emission of Cherenkov radiation but interference) : field clipping - radiation • Metal / Teflon conical target (5 mm aperture) (with the emission of Cherenkov radiation but interference) : field clipping - radiation • Simulations using Vsim – Konstantin • • Need to extract the power spectrum to compare with measurements Extrapolation to lower - higher beam energies Extrapolation to smaller aperture Extrapolation to material • Calculations Alessandro / Alexander • Discussion • • • Novelty / First systematic measurements of shadowing with different materials Several mechanism are clearly visible and were not anticipated. . Impact / General interest for the optimisation of THz power production based on short bunches - for DWA ? Journal : Trying PRX – PRA – can it be better Nature physics/comm?