Up-frequency conversion in a two-resonant-wave high-gain free-electron-laser amplifier

A free-electron laser is able to resonate at two different frequencies, both in free space and in a waveguide. The two waves have positive and negative slippage. We describe the nonlinear interaction between the two waves by a set of partial differential equations which in free space do not require the slowly varying envelope approximation (SVEA). In a waveguide a less restrictive SVEA is applied to each wave. By injecting a small signal at the low frequency, a strong signal and bunching are produced at the high frequency. This effect suggests a new method of generating short wavelength radiation

Host preferences of phlebotomine sand flies at a hypoendemic focus of canine leishmaniasis in central Italy.

A survey was carried out on phlebotomine sand flies and their feeding habits at a hypoendemic focus of Leishmania infantum in Macerata province, central Italy. During two consecutive years (2000-2001), 1465 sand fly specimens (42.5% of which were males) were collected from a variety of diurnal resting sites in the municipality of Camerino. The most prevalent species was Phlebotomus perniciosus (76.6%), followed by P. papatasi (10.4%), Sergentomyia minuta (9.1%), Phlebotomus perfiliewi (3.3%) and P. mascittii (0.5%). Among the 842 females collected, 578 (68.6%) were blood-fed. Based on the results of blood meal analyses, P. perniciosus fed on man, dogs, equines, sheep and birds; P. perfiliewi on dogs, equines, sheep and birds; P. papatasi on dogs, equines and birds. Two specimens of P. mascittii fed on equines. Forage ratios (FRs) and host selectivity indices gave different results for the large domestic animals. More than 95% of the specimens collected inside a stable, dog kennel, sheep pen and chicken house were found to have fed on the animals housed in the respective shelters. In addition, at one collecting site where almost all the hosts mentioned above were present simultaneously, both P. perniciosus and P. perfiliewi were found to have fed on all five species, indicating that host choice was probably related to its availability (i.e. number and size) rather than specific attractiveness. The feeding habits of the two Leishmania vectors may have implications for the epidemiology of leishmaniasis in urban and peri-urban areas, where sand fly females deprived of other vertebrate hosts (particularly the larger species) may begin to bite humans and dogs more frequently

Transverse effects in the production of x rays with a free-electron laser based on an optical undulator

The interaction between high-brilliance electron beams and counterpropagating laser pulses produces x rays via Thomson backscattering. If the laser source is long and intense enough, the electrons of the beam can bunch on the scale of the emitted x-ray wavelength and a regime of collective effects can establish. In this case of dominating collective effects, the FEL instability can develop and the system behaves like a free-electron laser based on an optical undulator. Coherent x rays can be irradiated, with a bandwidth very much thinner than that of the corresponding incoherent emission. The emittance of the electron beam and the distribution nonuniformity of the laser energy are the principal quantities that limit the growth of the x-ray signal. In this work we analyze with a 3D code the transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical laser pulse and the x-ray spectra obtained. The scalings typical of the optical wiggler, characterized by very short gain lengths and overall time durations of the process, make possible considerable emission also in violation of the Pellegrini criterion for static wigglers. A generalized form of this criterion is validated on the basis of the numerical evidence

Compensation of Non-Linear Bandwidth Broadening by Laser Chirping in Thomson Sources

A new laser chirping prescription is derived by means of the phase-stationary method for an inci- dent Gaussian laser pulse in conjunction with a Li enard-Wiechert calculation of the scattered radia- tion flux and spectral brilliance. This particularly efficient laser chirp has been obtained using the electric field of the laser and for electrons and radiation on axis. The frequency modulation is some- what reduced with respect to that proposed in the previous literature, allowing the application of this procedure to lasers with larger values of the parameter a0. Numerical calculations have been performed using mildly focused and narrow bandwidth laser pulses, confirming a larger efficiency of the chirp prescription here introduced. The chirp efficiency has been analysed as a function of the laser parameter and focusing. Published by AIP Publishing

High intensity X/ γ photon beams for nuclear physics and photonics

In this manuscript we review the challenges of Compton back-scattering sources in advancing photon beam performances in the1−20MeVenergy range, underlining the design criteria bringing tomaximum spectral luminosity and briefly describing the main achieve-ments in conceiving and developing new devices (multi-bunch RF cav-ities and Laser recirculators) for the case of ELI-NP Gamma BeamSystem (ELI-NP-GBS)

About the eastern limit of distribution of Phlebotomus ariasi (Diptera: Psychodidae)

Cette note fait part des resultats des enquetes entomologiques menees en 1995 dans les provinces de la region de Ligurie (Italie) pendant la periode d'activite des phlebotomes Un total de 2 216 phlebotomes a ete recolte dans quatre provinces en l'espace de 3 mois. Les especes suivantes ont ete identifiees : Phlebotomus perniciosus (31,8 %), P. ariasi (0,8 %) et Sergentomyia minuta (67,4 %). P. perniciosus, vecteur de leishmaniose viscerale en Italie, a ete recolte dans toutes les stations positives. Au contraire, P. ariasi a ete capture seulement dans les provinces d'Imperia et de Savona. La repartition geographique orientale de P. ariasi fait l'objet d'une discussion

The External-Injection experiment at the SPARC_LAB facility

At the SPARC_LAB facility of INFN-LNF we are installing a transport lines for ultra-short electron bunches and another for ultra-intense laser pulses,generated by the SPARC photo-injector and by the FLAME laser in asynchronized fashion at the tens of fs level,to co-propagate inside a hydrogen filled glass capillary,in order to perform acceleration of the electron bunch by a plasma wave driven by the laser pulse.The main aim of this experiment is to demonstrate that a high brightness electron beam can be accelerated by a plasma wave without any significant degradation of its quality.Motivations of the technical choices are made and expected performances are reporte

The PLASMONX Project for advanced beam physics experiments

The Project PLASMONX is well progressing into its design phase and has entered as well its second phase of procurements for main components. The project foresees the installation at LNF of a Ti:Sa laser system (peak power > 170 TW), synchronized to the high brightness electron beam produced by the SPARC photo-injector. The advancement of the procurement of such a laser system is reported, as well as the construction plans of a new building at LNF to host a dedicated laboratory for high intensity photon beam experiments (High Intensity Laser Laboratory). Several experiments are foreseen using this complex facility, mainly in the high gradient plasma acceleration field and in the field of mono- chromatic ultra-fast X-ray pulse generation via Thomson back-scattering. Detailed numerical simulations have been carried out to study the generation of tightly focused electron bunches to collide with laser pulses in the Thomson source: results on the emitted spectra of X-rays are presented

Evaluation of rK39 rapid diagnostic tests for canine visceral leishmaniasis : longitudinal study and meta-analysis

Canine visceral leishmaniasis is a vector-borne disease caused by the intracellular parasite Leishmania infantum. It is an important veterinary disease, and dogs are also the main animal reservoir for human infection. The disease is widespread in the Mediterranean area, and parts of Asia and South and Central America, and is potentially fatal in both dogs and humans unless treated. Diagnosis of canine infections requires serological or molecular tests. Detection of infection in dogs is important prior to treatment, and in epidemiological studies and control programmes, and a sensitive and specific rapid diagnostic test would be very useful. Rapid diagnostic tests (RDTs) have been developed, but their diagnostic performance has been reported to be variable. We evaluated the sensitivity of a RDT based on serological detection of the rK39 antigen in a cohort of naturally infected Brazilian dogs. The sensitivity of the test to detect infection was relatively low, but increased with time since infection and the severity of infection. We then carried out a meta-analysis of published studies of rK39 RDTs, evaluating the sensitivity to detect disease and infection. The results suggest that rK39 RDTs may be useful in a veterinary clinical setting, but the sensitivity to detect infection is too low for operational control programmes