Spectrum tailoring of low charge-to-mass ion beam by the triple-stage acceleration mechanism

Abstract

Lower charge-to-mass ions are more difficult to be accelerated during the traditional single accelerating progress, because they are generally modulated by the weaker charge-separated electric field. In this paper, the cascaded target normal sheath acceleration (TNSA) mechanism is proposed to solve this issue in experiments, where the low charge-to-mass ions (C2+) generated from the first TNSA stage can be further tailored to a mono-energetic bunch by the peak of the sheath field in the additive TNSA stages. A simple numerical model is used to explain the experimental result and shows that the energetic spread of the ion beam can be further reduced from 27% to ∼1% by expanding the two-stage acceleration to triple-stage acceleration. Here, the sheath field works like a spectral knife that can control the peak energy and bandwidth of the spectra for the ions with any charge-to-mass ratio. More choices can be provided for many potential applications, such as ion therapy and nuclear physics.

Cascaded solenoid acceleration of vortex laser-driven collimated proton beam

“…The efficiency for the protons accelerated in the center region to the total incident proton beam is assumed to be much less than 11.5% because of the expansion of the incident proton beam on the second target. Our results prove that the final efficiency of cascade proton beam is greater than 27.5%, which is much higher than the previous cascaded acceleration case driven by traditional Gaussian laser [38][39][40][41][42][43]. The main reason is that LG laser effectively compresses the protons to the beam center, so that more protons can be accelerated in the second stage.…”

“…Recently, the cascaded TNSA mechanism has been proposed to actively tailor the Maxwell spectra of the proton beam into a narrower spectrum in experiments, while reducing the experimental requirements [38][39][40]. Initially, Pfotenhauer et al performed the cascaded TNSA experiments [38].…”

“…Initially, Pfotenhauer et al performed the cascaded TNSA experiments [38]. This was followed by coupling it with the double beam image technique to realize time and special calibration during experiments, realizing high-efficiency cascaded TNSA acceleration for proton [39] and C 2+ [40] beams. It is to be noted that although the quasi-monoenergetic ion beams were generated, the obtained cascaded TNSA efficiencies were quite low.…”

Electron and ion acceleration from femtosecond laser-plasma peeler scheme

“…Moreover, enhanced TNSA has been reported in various schemes, including but not limited to using cone-like targets [63][64][65][66], thin foil coated behind a long near-critical-density plasma [67][68][69], thin foil attached microwire arrays in front [70][71][72] and multi-picosecond laser pulses [73]. Cascaded ion acceleration has also been proposed in several different setups [74][75][76].…”