Soft laser-plasma X-ray source for differential absorption imaging of tracing elements in thin samples

The differential imaging technique is particularly suitable for the detection of small concentrations of contrasts agents for biological and medical applications in samples using X-ray radiography. In this paper, we present an application of this technique using a laser-plasma soft X-ray source combined with a bent crystal. Using a Fresnel plate as a test object, we were able to obtain spatial resolutions of the order of a few tens of microns. The use of our configuration to perform differential imaging of a test-sample at the L2 edge of Br at 1,596 eV is finally demonstrated

A new line for laser-driven light ions acceleration and related TNSA studies

In this paper, we present the status of the line for laser-driven light ions acceleration (L3IA) currently under implementation at the Intense Laser Irradiation Laboratory (ILIL), and we provide an overview of the pilot experimental activity on laser-driven ion acceleration carried out in support of the design of the line. A description of the main components is given, including the laser, the beam transport line, the interaction chamber, and the diagnostics. A review of the main results obtained so far during the pilot experimental activity is also reported, including details of the laser-plasma interaction and ion beam characterization. A brief description of the preliminary results of a dedicated numerical modeling is also provided

A study of fast electron transport in high-intensity laser-matter interactions through X-ray imaging and spectroscopy

During the interaction of short and ultraintense laser pulses with solids a copious amount of so-called “fast” electrons is generated. These electrons have a kinetic energy much greater (hundreds of keV to a few MeV) than the bulk plasma electrons. The study of the physics underlying the generation of the fast electrons and the propagation of the fast electron beam in the substrate target material is of a great interest for a variety of research fields including the Fast Ignition (FI) scheme to Inertial Confinement Fusion. In the FI scheme, a fast electron beam generated through the interaction of a PetaWatt laser beam with the pellet at the time of maximum compression, is envisaged to deposit its energy in the core of the fuel capsule thus igniting the fuel. The demonstration of the feasibility of inertial fusion energy using the FI scheme is the main goal of the High Power laser Energy Research Facility (HiPER), currently under preparation in Europe and in Italy. In this thesis, fundamental experimental studies of fast electron generation and transport phenomena carried out at the home CNR laboratory and at the large scale facility at the Rutherford Appleton Laboratory using spectroscopy and monochromatic imaging of the produced X-ray self-emission are presented. In particular, some of the key parameters of the system required for the study of feasibility of the FI scheme, such as the fast electron mean energy and the fast electron beam divergence are addressed. The main diagnostic techniques employed for the investigation of the fast electron transport phenomena are described. Moreover, a novel diagnostic technique based on an X-ray pinhole camera equipped with a CCD working in single-photon regime is presented. With this technique, monochromatic X-ray images can be obtained simultaneously at different photon energies in a wide photon energy range, to explore the dynamics of fast electron propagation in complex targets/systems

Laser-driven sources of high energy particles and radiation: lecture notes of the "Capri" Advanced Summer School

This volume presents a selection of articles based on inspiring lectures held at the “Capri” Advanced Summer School, an original event conceived and promoted by Leonida Antonio Gizzi and Ralph Assmann that focuses on novel schemes for plasma-based particle acceleration and radiation sources, and which brings together researchers from the conventional accelerator community and from the high-intensity laser-matter interaction research fields. Training in these fields is highly relevant for ultra-intense lasers and applications, which have enjoyed dramatic growth following the development of major European infrastructures like the Extreme Light Infrastructure (ELI) and the EuPRAXIA project. The articles preserve the tutorial character of the lectures and reflect the latest advances in their respective fields. The volume is mainly intended for PhD students and young researchers getting started in this area, but also for scientists from other fields who are interested in the latest developments. The content will also appeal to radiobiologists and medical physicists, as it includes contributions on potential applications of laser-based particle accelerators

Lasers for Novel Accelerators

International audienceSignificant progress has been made over the last decade in optical laser performance including repetition rate, average and peak power, and laser-system footprint making these systems attractive for many applications including novel accelerators. Most novel acceleration schemes require high-power lasers. The talk will present drive laser requirements for current novel accelerator schemes, industry plans to meet these requirements, and the future for high-power lasers

Thomson Scattering Imaging From Ultrashort Ultraintense Laser Interaction With Gas

Laser–plasma acceleration can provide acceleration gradients which are thousands of times stronger than conventional electron accelerators. The laser propagation length is a crucial parameter that must be extended to achieve high-energy electrons. Here, we show that color images of the laser–plasma interaction region taken from the direction perpendicular to the polarization plane are a powerful tool to discriminate between Thomson scattering and plasma self-emission, leading to a precise measurement of the propagation length

Focusing and stabilizing laser?plasma-generated electron beams with magnetic devices

External magnetic devices have been successfully tested to control the divergence and pointing stability of subrelativistic electron beams accelerated by ultrashort laser pulses in a nitrogen plasma (electron density of >1019cm%3). Different configurations of the magnetic devices have been studied, and their effects are discussed in detail. The analysis is also supported by the results of ray-tracing simulations using the first-order trajectory equation in the magnetic field configurations. This simple method of improving beam stability will be particularly useful for applying laser generated ultrashort electron beams to high-dose radiobiological studies. © 2014 The Japan Society of Applied Physic

A Few MeV Laser-Plasma Accelerated Proton Beam in Air Collimated Using Compact Permanent Quadrupole Magnets

Proton laser-plasma-based acceleration has nowadays achieved a substantial maturity allowing to seek for possible practical applications, as for example Particle Induced X-ray Emission with few MeV protons. Here we report about the design, implementation, and characterization of a few MeV laser-plasma-accelerated proton beamline in air using a compact and cost-effective beam transport line based on permanent quadrupole magnets. The magnetic beamline coupled with a laser-plasma source based on a 14-TW laser results in a well-collimated proton beam of about 10 mm in diameter propagating in air over a few cm distance

Patterns of regional brain hypometabolism associated with knowledge of semantic features and categories in Alzheimer's disease

The study of semantic memory in patients with Alzheimer's disease (AD) has raised important questions about the representation of conceptual knowledge in the human brain. It is still unknown whether semantic memory impairments are caused by localized damage to specialized regions or by diffuse damage to distributed representations within nonspecialized brain areas. To our knowledge, there have been no direct correlations of neuroimaging of in vivo brain function in AD with performance on tasks differentially addressing visual and functional knowledge of living and nonliving concepts. We used a semantic verification task and resting 18-fluorodeoxyglucose positron emission tomography in a group of mild to moderate AD patients to investigate this issue. The four task conditions required semantic knowledge of (1) visual, (2) functional properties of living objects, and (3) visual or (4) functional properties of nonliving objects. Visual property verification of living objects was significantly correlated with left posterior fusiform gyrus metabolism (Brodmann's area [BA] 37/19). Effects of visual and functional property verification for nonliving objects largely overlapped in the left anterior temporal (BA 38/20) and bilateral premotor areas (BA 6), with the visual condition extending more into left lateral precentral areas. There were no associations with functional property verification for living concepts. Our results provide strong support for anatomically separable representations of living and nonliving concepts, as well as visual feature knowledge of living objects, and against distributed accounts of semantic memory that view visual and functional features of living and nonliving objects as distributed across a common set of brain area