High Power Laser Science and Engineering, 2017, 5 (2): 02000e12, Published Online: Jul. 26, 2018
An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments
Figures & Tables
Fig. 1. Schematic of nFTPS. Plastic film targets cover the holes on the target holders (bottom left), which are then mounted in the target wheel. The diameter of target holes is $500~\unicode[STIX]{x03BC}\text{m}$ and the distance between two holes along the same radial line is 2.5 mm, the angle between two adjacent radial lines is $0.903^{\circ }$ . An adjustable microscope can be moved independently to observe and position individual targets in transverse direction $(x{-}y)$ . The chromatic distance sensor is used to adjust the longitudinal target position $(z)$ .
Fig. 2. Deviation (in $z$ -axis) distribution of 1683 targets (17 holders) and corresponding normal distribution fit. After positioning all targets via the microscope and distance sensor, the displacements after repositioning are shown blue. The measurements are performed in vacuum condition. $\unicode[STIX]{x1D70E}$ is the standard deviation.
Fig. 3. The trend of average deviations after movement for different hexapod velocities. Each point represents the average deviation for 99 targets of one holder, which were measured via the same procedure as described for Figure 2 . The error bars represent the standard deviation of 99 data points.
Fig. 4. (a) System vibration induced by ceasing hexapod with speed of $12.5~\text{mm}/\text{s}$ , (b) the corresponding Fast Fourier Transform and (c) beating frequency simulation. The real time displacements are measured on one film target with the distance sensor after hexapod movement with speed of $12.5~\text{mm}/\text{s}$ in vacuum condition.
Fig. 5. (a) Measured spectra of proton kinetic energies (color bars) and their corresponding distribution of maximum energies. The error bars of single shot results represent the accuracy of the maximum energy determined by the wide angle magnetic spectrometer. The part between the two dashed lines correlates to $5.1{-}9~\text{MeV}$ , where 95% of shots’ cutoff energies are located and $\unicode[STIX]{x1D70E}$ is the corresponding standard deviation. (top). (b) Proton numbers per milli-steradian per 1% kinetic energy at three different kinetic energies: 4, 5 and 6 MeV. (bottom).
Ying Gao, Jianhui Bin, Daniel Haffa, Christian Kreuzer, Jens Hartmann, Martin Speicher, Florian H. Lindner, Tobias M. Ostermayr, Peter Hilz, Thomas F. Rösch, Sebastian Lehrack, Franz Englbrecht, Sebastian Seuferling, Max Gilljohann, Hao Ding, Wenjun Ma, Katia Parodi, Jörg Schreiber. An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments[J]. High Power Laser Science and Engineering, 2017, 5(2): 02000e12.
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