Application of nuclear emulsions for the identification of multi-MeV protons in laser ion acceleration experiments

Laser-driven multi-MeV high-purity proton acceleration via anisotropic ambipolar expansion of micron-scale hydrogen clusters

“…Figure 2 shows the energy spectra of laser-accelerated protons measured using the 7 7 cm integration-type detector unit with the CR-39 plate located along the laser propagation direction obtained at nozzle temperatures of 25 K and 50 K, where the ion signals were accumulated for 76 and 71 laser shots, respectively. For the case with a nozzle temperature of 25 K, the higher part of the energy spectrum obtained with the CR-39 plate is in good agreement with that obtained with the stack of nuclear emulsion films in the same series of experiments 50 , which confirms that the energy spectra measurements were conducted in a technically correct manner. The maximum energy of protons accelerating along the laser propagation direction is found to be 12.4 MeV with the number of protons 1.3 10 /MeV/sr/shot, while the number of protons with the lower energy of 2.8 MeV is found to be approximately 1.6 10 /MeV/sr/shot.…”

Laser-driven multi-MeV high-purity proton acceleration via anisotropic ambipolar expansion of micron-scale hydrogen clusters

“…Figure 2 shows the energy spectra of laser-accelerated protons measured using the 7 × 7 cm 2 integration-type detector unit with the CR-39 plate located along the laser propagation direction obtained at nozzle temperatures of 25 K and 50 K, where the ion signals were accumulated for 76 and 71 laser shots, respectively. For the case with a nozzle temperature of 25 K, the higher part of the energy spectrum obtained with the CR-39 plate is in good agreement with that obtained with the stack of nuclear emulsion films in the same series of experiments 50 , which confirms that the energy spectra measurements were conducted in a technically correct manner. The maximum energy of protons accelerating along the laser propagation direction is found to be 12.4±0.6 MeV with the number of protons 1.3±0.6 × 10 6 MeV/sr/shot, while the number of protons with the lower energy of 2.8±1.9 MeV is found to be approximately 1.6±0.3 × 10 9 /MeV/sr/shot.…”

Laser-driven multi-MeV high-purity proton acceleration via anisotropic ambipolar expansion of micron-scale hydrogen clusters

“…Figure 2 shows the energy spectra of laser-accelerated protons measured using the 7 × 7 cm 2 integration-type detector unit with the CR-39 plate located along the laser propagation direction obtained at nozzle temperatures of 25 K and 50 K, where the ion signals were accumulated for 76 and 71 laser shots, respectively. For the case with a nozzle temperature of 25 K, the higher part of the energy spectrum obtained with the CR-39 plate is in good agreement with that obtained with the stack of nuclear emulsion films in the same series of experiments 49 , which confirms that the energy spectra measurements were conducted in a technically correct manner. The maximum energy of protons accelerating along the laser propagation direction is found to be 12.4±0.6 MeV with the number of protons 1.3±0.6 × 10 6 MeV/sr/shot, while the number of protons with the lower energy of 2.8±1.9 MeV is found to be approximately 1.6±0.3 × 10 9 /MeV/sr/shot.…”

“…The energy spectra measured using the CR-39 plate with the stepwise energy filter at nozzle temperatures of 25 K (red solid line) and 50 K (blue broken line). The energy spectrum measured with the stack of nuclear emulsion films at the nozzle temperature of 25 K (green dotted line) is also shown as reference data 49 . The error bars on the y-axis represent the standard deviations of the etch pit/track counts, while those on the x-axis represent the measured energy range.…”