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Laser-driven ion accelerators are a promising alternative to conventional accelerators currently in use. Following the laser-plasma interaction, the target is destroyed, making it necessary to replenish it, a task particularly challenging in the case of state-of-the-art laser systems operating at multi-hertz repetition rates. Here, we will introduc...
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Context 1
... tape-drive system developed ( Fig. 1) has two spools that can allocate tens of metres of few-micron thick tape, allowing for thousands of consecutive shots, and several rods to guide the tape though and place it on the shooting position. Those spools are both attached to rotary motors, giving the possibility of moving the tape forward and backwards, which, for tapes ...
Context 2
... to change the shooting position, the main body is mounted over two motorised stages that can be remotely controlled and automatised. Moreover, these stages are used to precisely place the tape at the focal plane. Furthermore, the angle of incidence of the laser can also be precisely controlled using the micrometric screws (see Angle screws in Fig. 1a). Additionally, transverse probing of the interaction is enabled by a side window on the body of the tape-drive. Following the initial alignment of the system, the tape must remain stable on the focal plane as the target is replaced. In our case, this is achieved by using a closed-loop system which uses feedback from one of the rods. ...
Citations
... Several alternatives are being actively studied as potential target systems [5] . Some promising recent developments include the use of liquid targets [6] , liquid crystal targets [7,8] , high-density gas jets [9,10] , or cryogenic solid hydrogen targets [11,12] , all of which would ensure the operation for extended periods of time. ...
A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are introduced. The assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets, mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser irradiations. The automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target, which alongside the purpose-built design of the target wheel, enables operation at rates up to 10 Hz. Stable and continuous laser-driven proton acceleration at 10 Hz is demonstrated, with observed cut-off energy stability about 15%.
... As these targets are destroyed after their irradiation, they need to be replaced for a fresh one and re-aligned with few-microns-precision before a new irradiation takes place. Several solutions are currently being actively studied to address this limitation [7]. In our case, we are particularly focussed on the development of targetry systems for solid targets, specifically rotating wheels and tape drives. ...
... Despite the flexibility and robustness of the rotating wheel, this solution presents intrinsic shortcomings in the context of state-of-the-art laser systems, such as the maximum number of targets, typically constrained to a few thousand, or the maximum repetition rate of operation, due to the required separation between targets and maximum velocity for the wheel movements involved. For these reasons, we are currently working on the development of a tape-drive system [7]. In this case, a thin tape is used as target, ensuring a fresh surface interacts with the laser as the tape is wound onto a motorised spool [8]. ...
... By ensuring the tape remains at a constant tension as it slides between the rods defining the interaction point, the tape surface is ensured to remain stable on the focal plane as the target is replaced. Our tape drive system is currently being commissioned at the Laser Laboratory for Acceleration and Applications, with preliminary stability measurements already indicating standard deviations of the tape position <10 µm [7]. ...
In recent years, laser-driven accelerators have emerged as a promising technology for the development of compact and cost-effective sources of high-energy particles and radiation. Here, we introduce our research programme at the Laser Laboratory for Acceleration and Applications, which focusses on high-power laser systems, development of high-repetition rate targetry, and biomedical applications of laser-based accelerators. Our recent results include the generation of high-energy proton and ion beams through laser-plasma acceleration, which have potential applications in materials activation for medical imaging. We have also investigated the feasibility of using laser-driven X-rays and ion beams for radiobiological research, including FLASH therapy and hadron therapy.
