Time-Of-Flight (TOF) methods are very effective to detect particles accelerated in laser-plasma interactions, but they show significant limitations when used in experiments with high energy and intensity lasers, where both high-energy ions and remarkable levels of ElectroMagnetic Pulses (EMPs) in the radiofrequency-microwave range are generated. Here we describe a novel advanced diagnostic method for the characterization of protons accelerated by intense matter interactions with high-energy and high-intensity ultra-short laser pulses up to the femtosecond and even future attosecond range. The method employs a stacked diamond detector structure and the TOF technique, featuring high sensitivity, high resolution, high radiation hardness and high signal-to-noise ratio in environments heavily affected by remarkable EMP fields. A detailed study on the use, the optimization and the properties of a single module of the stack is here described for an experiment where a fast diamond detector is employed in an highly EMP-polluted environment. Accurate calibrated spectra of accelerated protons are presented from an experiment with the femtosecond Flame laser (beyond 100 TW power and ~ 1019 W/cm2 intensity) interacting with thin foil targets. The results can be readily applied to the case of complex stack configurations and to more general experimental conditions.
We describe the first electro-optical absolute measurements of electromagnetic pulses (EMPs) generated by laser-plasma interaction in nanosecond regime. Laser intensities are inertial-confinement-fusion (ICF) relevant and wavelength is 1054 nm. These are the first direct EMP amplitude measurements with the detector rather close and in direct view of the plasma. A maximum field of 261 kV/m was measured, two orders of magnitude higher than previous measurements by conductive probes on nanosecond regime lasers with much higher energy. The analysis of measurements and of particle-in-cell simulations indicates that signals match the emission of charged particles detected in the same experiment, and suggests that anisotropic particle emission from target, X-ray photoionization and charge implantation on surfaces directly exposed to plasma, could be important EMP contributions. Significant information achieved on EMP features and sources is crucial for future plants of laser-plasma acceleration and inertial-confinement-fusion and for the use as effective plasma diagnostics. It also opens to remarkable applications of laser-plasma interaction as intense source of RF-microwaves for studies on materials and devices, EMP-radiation-hardening and electromagnetic compatibility. The demonstrated extreme effectivity of electric-fields detection in laser-plasma context by electro-optic effect, leads to great potential for characterization of laser-plasma interaction and generated Terahertz radiation.
Although in our experience the haptics still seem weak and the diaphragm diameter too large, implantation of the black-diaphragm IOL type 67F appeared sufficiently safe and provided satisfactory functional results for correction of post-traumatic aniridia combined with cataract or aphakia, improving BCVA and reducing glare and photophobia in most patients, though clearly more cases and longer follow-up are needed to assess its clinical performance properly.
In this work, we describe the results of experiments performed at the femtosecond ECLIPSE laser facility at CELIA in Bordeaux. We irradiated targets constituted by aluminum foils of various thicknesses and characterized the accelerated protons with energies in the range of interest for p+ 11 B nuclear fusion. Time-of-flight measurements were performed by using Chemical Vapor Deposition (CVD) monocrystalline diamond detectors, which are specifically designed to operate in harsh environments where large ElectroMagnetic Pulses (EMPs) are generated during laser-target interaction. The 1 Hz high repetition rate used for the ECLIPSE laser allowed the collection of a large number of similar shots, giving therefore a large statistics to accurately characterize the energy spectrum of the laser-plasma accelerated protons. The laser repetitivity at a relatively small intensity permits to improve the signal-to-noise ratio of the detection of the products of low cross-section reactions, such as the p+ 11 B one, by their collection over a large number of similar shots.
K: Diamond Detectors; Plasma diagnostics -charged-particle spectroscopy 1Corresponding author.
The paper reports about the use of single-crystal Chemical Vapour Deposited (CVD) diamonds as radiation detectors in laser-matter interaction experiments on the ABC laser in ENEA -Frascati. The detectors have been designed and realized by University of Tor Vergata -Rome. The interdigital configuration and the new design of the bias-tee voltage supply units guarantee a fast time response. The detectors are sensitive to soft-X photons and to particles. A remarkable immunity to electromagnetic noise, associated with the laser-target interaction, makes them especially useful for the measurements of the time of flight of fast particles. A novel diamond assembly has been tested in plasmas generated by the ABC laser in the nanosecond regime at intensities I = 10 13÷14 W/cm 2 , where contributions from X rays, fast electrons and ions could be observed.
K: Diamond Detectors; Plasma diagnostics -charged-particle spectroscopy; Plasma generation (laser-produced, RF, x ray-produced); X-ray detectors 1Corresponding author.
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