The integrated low-level trigger and data acquisition (TDAQ) system of the NA62 experiment at CERN is described. The requirements of a large and fast data reduction in a high-rate environment for a ...medium-scale, distributed ensemble of many different sub-detectors led to the concept of a fully digital integrated system with good scaling capabilities. The NA62 TDAQ system is rather unique in allowing full flexibility on this scale, allowing in principle any information available from the detector to be used for triggering. The design concept, implementation and performances from the first years of running are illustrated.
Next-generation plasma-based accelerators can push electron bunches to gigaelectronvolt energies within centimetre distances1,2. The plasma, excited by a driver pulse, generates large electric fields ...that can efficiently accelerate a trailing witness bunch3–5, enabling the realization of laboratory-scale applications ranging from high-energy colliders6 to ultrabright light sources7. So far, several experiments have demonstrated large accelerations8–10 but the resulting beam quality, particularly the energy spread, is still far from state-of-the-art conventional accelerators. Here we show the results of a beam-driven plasma acceleration experiment where we used an electron bunch as a driver followed by an ultrashort witness bunch. By setting a positive energy chirp on the witness bunch, its longitudinal phase space is rotated during acceleration, resulting in an ultralow energy spread that is even lower than the spread at the plasma entrance. This result will significantly impact the optimization of the plasma acceleration process and its implementation in forthcoming compact machines for user-oriented applications.In a beam-driven plasma wakefield accelerator, the energy spread of an electron bunch is reduced with respect to the plasma entrance, which is achieved through setting a positive energy chirp that rotates the bunches’ longitudinal phase space.
The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in the field of next-generation compact and cost affordable particle ...accelerators, to be used in many fields for industrial, medical, and research applications. The ability to shape the beam longitudinal phase space, in particular, plays a key role in achieving high-peak brightness. Here we present a new approach that allows us to tune the longitudinal phase space of a high-brightness beam by means of plasma wakefields. The electron beam passing through the plasma drives large wakefields that are used to manipulate the time-energy correlation of particles along the beam itself. We experimentally demonstrate that such a solution is highly tunable by simply adjusting the density of the plasma and can be used to imprint or remove any correlation onto the beam. This is a fundamental requirement when dealing with largely time-energy correlated beams coming from future plasma accelerators.
Sprouting angiogenesis consists of the expansion and remodelling of existing vessels, where the vascular sprouts connect each other to form new vascular loops. Endothelial Progenitor Cells (EPCs) are ...a subtype of stem cells, with high proliferative potential, able to differentiate into mature Endothelial Cells (ECs) during the neovascularization process. In addition to this direct structural role EPCs improve neovascularization, also secreting numerous pro-angiogenic factors able to enhance the proliferation, survival and function of mature ECs, and other surrounding progenitor cells. While sprouting angiogenesis by mature ECs involves resident ECs, the vasculogenic contribution of EPCs is a high hurdle race. Bone marrowmobilized EPCs have to detach from the stem cell niche, intravasate into bone marrow vessels, reach the hypoxic area or tumour site, extravasate and incorporate into the new vessel lumen, thus complementing the resident mature ECs in sprouting angiogenesis. The goal of this review is to highlight the role of the main protease systems able to control each of these steps. The pivotal protease systems here described, involved in vascular patterning in sprouting angiogenesis, are the matrix-metalloproteinases (MMPs), the serineproteinases urokinase-type plasminogen activator (uPA) associated with its receptor (uPAR) and receptorassociated plasminogen/plasmin, the neutrophil elastase and the cathepsins. Since angiogenesis plays a critical role not only in physiological but also in pathological processes, such as in tumours, controlling the contribution of EPCs to the angiogenic process, through the regulation of the protease systems involved, could yield new opportunities for the therapeutic prospect of efficient control of pathological angiogenesis.
The possibility to accelerate electron beams to ultra-relativistic velocities over short distances by using plasma-based technology holds the potential for a revolution in the field of particle ...accelerators
. The compact nature of plasma-based accelerators would allow the realization of table-top machines capable of driving a free-electron laser (FEL)
, a formidable tool to investigate matter at the sub-atomic level by generating coherent light pulses with sub-ångström wavelengths and sub-femtosecond durations
. So far, however, the high-energy electron beams required to operate FELs had to be obtained through the use of conventional large-size radio-frequency (RF) accelerators, bound to a sizeable footprint as a result of their limited accelerating fields. Here we report the experimental evidence of FEL lasing by a compact (3-cm) particle-beam-driven plasma accelerator. The accelerated beams are completely characterized in the six-dimensional phase space and have high quality, comparable with state-of-the-art accelerators
. This allowed the observation of narrow-band amplified radiation in the infrared range with typical exponential growth of its intensity over six consecutive undulators. This proof-of-principle experiment represents a fundamental milestone in the use of plasma-based accelerators, contributing to the development of next-generation compact facilities for user-oriented applications
.
Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for ...a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.
We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. We ...experimentally prove that the guiding is much less affected by the beam chromatic dispersion with respect to a conventional bending magnet and, with the support of numerical simulations, we show that it can even be made dispersionless by employing larger discharge currents. This proof-of-principle experiment extends the use of plasma-based devices, that revolutionized the field of particle accelerators enabling the generation of GeV beams in few centimeters. Compared to state-of-the-art technology based on conventional bending magnets and quadrupole lenses, these results provide a compact and affordable solution for the development of next-generation tabletop facilities.
The generation of ultra-short electron bunches with ultra-low timing-jitter relative to the photo-cathode (PC) laser has been experimentally proved for the first time at the SPARC_LAB test-facility ...(INFN-LNF, Frascati) exploiting a two-stage hybrid compression scheme. The first stage employs RF-based compression (velocity-bunching), which shortens the bunch and imprints an energy chirp on it. The second stage is performed in a non-isochronous dogleg line, where the compression is completed resulting in a final bunch duration below 90 fs (rms). At the same time, the beam arrival timing-jitter with respect to the PC laser has been measured to be lower than 20 fs (rms). The reported results have been validated with numerical simulations.
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