Matthew Allen

Intense ion beams accelerated by relativistic laser plasmas

We have studied the influence of the target properties on laser-accelerated proton and ion beams generated by the LULI multi-terawatt laser. A strong dependence of the ion emission on the surface conditions, conductivity, shape and material of the thin foil targets were observed. We have performed a full characterization of the ion beam using magnetic spectrometers, Thompson parabolas, radiochromic film and nuclear activation techniques. The strong dependence of the ion beam acceleration on the conditions on the target back surface was found in agreement with theoretical predictions based on the target normal sheath acceleration (TNSA) mechanism. Proton kinetic energies up to 25 MeV have been observed.

Intense ion beams accelerated by ultra-intense laser pulses

The discovery of intense ion beams off solid targets irradiated by ultra-intense laser pulses has become the subject of extensive international interest. These highly collimated, energetic beams of protons and heavy ions are strongly depending on the laser parameters as well as on the properties of the irradiated targets. Therefore we have studied the influence of the target conditions on laser-accelerated ion beams generated by multi-terawatt lasers. The experiments were performed using the 100 TW laser facility at Laboratoire pour l’Utilisation des Laser Intense (LULI). The targets were irradiated by pulses up to 5×1019 W/cm2 (∼300 fs,λ=1.05 μm) at normal incidence. A strong dependence on the surface conditions, conductivity, shape and purity was observed. The plasma density on the front and rear surface was determined by laser interferometry. We characterized the ion beam by means of magnetic spectrometers, radiochromic film, nuclear activation and Thompson parabolas. The strong dependence of the ion b...

Intense, high-quality ion beams generated by ultra-intense lasers

The advent of ultra-intense short-pulse laser systems has opened the field of relativistic laser-generated plasmas in which the electron temperature exceeds several MeV. One particularly exciting topic of recent interest has been the discovery of intense, collimated, energetic beams of ions off the back surface of solid targets. The beam currents exceed several hundreds of kiloamperes at a pulse duration of only a few picoseconds.

Short Pulse Laser Driven Ion Beams — Experiments and Applications

We present the results of a study on the acceleration of intense ion beams from solid targets irradiated with laser intensities up to 5×1019W/cm2. A strong dependence of the ion beam parameters on the conditions on the target conditions and laser parameter was found. The ion beam characteristic revealed a highly laminar acceleration and an excellent beam quality superior to that from conventional accelerators. We succeeded in shaping the ion beam by the appropriate tailoring of the target geometry and we performed a characterization of the ion beam quality. The production of a heavy ion beam could be achieved by suppressing the amount of protons at the target surfaces. Finally, we demonstrated the use of short pulse laser driven ion beams for radiography of thick samples with high resolution.