Tightly focused proton beams generated from helical coil targets have been shown to be highly collimated across small distances, and display characteristic spectral bunching. We show, for the first time, proton spectr...Tightly focused proton beams generated from helical coil targets have been shown to be highly collimated across small distances, and display characteristic spectral bunching. We show, for the first time, proton spectra from such targets at high resolution via a Thomson parabola spectrometer. The proton spectral peaks reach energies above 50 MeV, with cutoffs approaching 70 MeV and particle numbers greater than 10^(10). The spectral bunch width has also been measured as low as approximately 8.5 MeV(17% energy spread). The proton beam pointing and divergence measured at metrescale distances are found to be stable with the average pointing stability below 10 mrad, and average half-angle beam divergences of approximately 6 mrad. Evidence of the influence of the final turn of the coil on beam pointing over long distances is also presented, corroborated by particle tracing simulations, indicating the scope for further improvement and control of the beam pointing with modifying target parameters.展开更多
基金funding from EPSRC(EP/P010059/1 and EP/K022415/1)the IMPULSE project by the European Union Framework Program for Research and Innovation Horizon 2020(grant agreement No.871161)+1 种基金support of the target fabrication and mechanical engineering staff of the Central Laser Facility,STFC,UKKelvin2 cluster at the Northern Ireland High Performance Computing(NI-HPC)facility funded by EPSRC(EP/T022175)for providing computational resources
文摘Tightly focused proton beams generated from helical coil targets have been shown to be highly collimated across small distances, and display characteristic spectral bunching. We show, for the first time, proton spectra from such targets at high resolution via a Thomson parabola spectrometer. The proton spectral peaks reach energies above 50 MeV, with cutoffs approaching 70 MeV and particle numbers greater than 10^(10). The spectral bunch width has also been measured as low as approximately 8.5 MeV(17% energy spread). The proton beam pointing and divergence measured at metrescale distances are found to be stable with the average pointing stability below 10 mrad, and average half-angle beam divergences of approximately 6 mrad. Evidence of the influence of the final turn of the coil on beam pointing over long distances is also presented, corroborated by particle tracing simulations, indicating the scope for further improvement and control of the beam pointing with modifying target parameters.
