121 research outputs found
Influence of the ablation threshold on laser driven acceleration
No full textLaser ablation threshold measurements has been carried out by the nanosecond-class Nd:YAG laser at LNS-INFN in Catania. Advanced targets, such as hydrogen-enriched silicon slabs and sub-micro structured polymeric samples, have been investigated. The estimated ablation fluences are correlated to recent experimental and theoretical results on high intensity laser driven ion acceleration. Characteristics of H-atoms/protons and heavier atoms/ions coming out from the bulk of the irradiated target or from surface contaminants have been determined by optical and time-of-flight spectroscopy as well as mass quadrupole spectrometry
Experimental test of TOF diagnostics for PW class lasers
No full textNew particle acceleration regimes driven by PW class lasers imply the development of new in-situ diagnostics. Before constructing new types of detectors one must test currently available diagnostics in these new regimes of high intensity laser-matter interaction. Experimental tests on two types of time of flight detectors are presented, demonstrating the possibility of their measuring capabilities in harsh conditions, namely the strong laser induced electromagnetic pulse. A recently developed silicon carbide detector was successfully tested and particle beams were characterized. Further tests were performed on a detector based on secondary emission of electrons during the transition of laser accelerated particle beams. The presented results show a clear consistency and sufficient capabilities for high intensity laser driven particle beam detection. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only
Multi probes measurements at the PALS Facility Research Centre during high intense laser pulse interactions with various target materials
No full textDuring the interaction of high intense laser pulse with solid target, a large amount of hot electrons is produced and a giant Electromagnetic Pulse (EMP) is generated due to the current flowing into the system target–target holder, as well as due to the escaping charged particles in vacuum. EMP production for different target materials is investigated inside and outside the target chamber, using monopole antenna, super wide-band microstrip antenna and Moebius antenna. The EMP consists in a fast transient magnetic field lasting hundreds of nanosecond with frequencies ranging from MHz to tens of GHz. Measurements of magnetic field and return target current in the range of kA were carried out by an inductive target probe (Cikhardt J. et al. Rev. Sci. Instrum. 85 (2014) 103507)
A Compact "Water Window" Microscope with 60 nm Spatial Resolution for Applications in Biology and Nanotechnology
No full textShort illumination wavelength allows an extension of the diffraction limit toward nanometer scale; thus, improving spatial resolution in optical systems. Soft X-ray (SXR) radiation, from "water window" spectral range, λ=2.3-4.4 nm wavelength, which is particularly suitable for biological imaging due to natural optical contrast provides better spatial resolution than one obtained with visible light microscopes. The high contrast in the "water window" is obtained because of selective radiation absorption by carbon and water, which are constituents of the biological samples. The development of SXR microscopes permits the visualization of features on the nanometer scale, but often with a tradeoff, which can be seen between the exposure time and the size and complexity of the microscopes. Thus, herein, we present a desk-top system, which overcomes the already mentioned limitations and is capable of resolving 60 nm features with very short exposure time. Even though the system is in its initial stage of development, we present different applications of the system for biology and nanotechnology. Construction of the microscope with recently acquired images of various samples will be presented and discussed. Such a high resolution imaging system represents an interesting solution for biomedical, material science, and nanotechnology applications
Table-top water-window soft X-ray microscope using a Z-pinching capillary discharge source
No full textThe development and demonstration of a table-top transmission soft X-ray (SXR) microscope, using a laboratory incoherent capillary discharge source has been carried out. This Z-pinching capillary discharge water-window SXR source, is a first of its kind to be used for high spatial resolution microscopy at λ = 2.88 nm (430 eV) . A grazing incidence ellipsoidal condenser mirror is used for focusing of the SXR radiation at the sample plane. The Fresnel zone plate objective lens is used for imaging of the sample onto a back-illuminated (BI) CCD camera. The achieved half-pitch spatial resolution of the microscope approaches 100 nm, as demonstrated by the knife-edge test. Details about the source, and the construction of the microscope are presented and discussed. Additionally, the SXR images of various samples, proving applicability of such microscope for observation of objects in the nanoscale, are shown
Physics and technology towards electron acceleration with high repetition rate lasers
No full textTato práce ukazuje vývoj inovativního aplikačního zařízení, spočívajícího ve zdroji ultrarelativistických elektronových svazků urychlovaných laserem s opakovací frekvencí 1 kHz ve výzkumném centru ELI Beamlines. Techniku urychlování laserem generovanou brázdovou vlnou využíváme k vytváření elektronových svazků se světově rekordní energii pro opakovací frekvencí 1 kHz, což povede k pokroku ve výzkumu laserového urychlování s vysokou opakovací frekvencí a dovolí realizovat nové vědecké aplikace. Detailně jsou prezentovány fyzika a nutný technologický vývoj jak v oblasti laserového zdroje, tak i v oblasti lasero-plazmového urychlovače včetně nutné diagnostiky a řešených problémů. Celá práce byla provedena a koordinována autorem s myšlenkou vytvořit zařízení na nejvyšší světové úrovni, schopné plně pracovat na opakovací frekvenci 1 kHz, které umožní jak experimenty s urychlováním laserem generovanou brázdovou vlnou a ozařovací experimenty, tak i generaci sekundárních zdrojů (tj. rentgenového záření, pozitronů), založených na elektronových svazcích.The work shows the development of an innovative beamline consisting in a source of ultrarelativistic electron beams accelerated by a 1 kHz repetition rate laser at the ELI-Beamlines research facility. We make use of the Laser Wakefield Acceleration technique to produce high-quality world record energy 1 kHz electron beams, that will push forward the high repetition rate laser-driven acceleration research field and will allow the realization of new scientific applications. The physics and the necessary technological developments concerning both the laser driver and the laser-plasma accelerator, including the necessary diagnostics and problems solved, are presented in detail. All the work has been done and coordinated by the author with the idea to establish a state-of-the-art beamline, able to fully work at 1 kHz, allowing both LWFA experiments, and irradiation experiments as well as the generation of secondary sources (i.e. x-rays, positrons) based on the electron beams
Numerical simulations of jet formation in laser-target interactions
No full textCylindrical version of our two-dimensional Arbitrary Lagrangian Eulerian code PALE is applied for numerical studies of dense plasma jet formation from laser targets. Well collimated plasma expansion from a massive solid target irradiated by a single laser beam with a special profile is investigated. Particular interaction beam profile with intensity minimum in the beam centre is found to be responsible for jet formation during plasma expansion. A deep concave interaction beam profile at PALS is obtained from our simulation of the laser propagation in the amplifying chain and in the focusing system
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