Thermal simulations for optical transition radiation screen for Eli-NP compton gamma source

The ELI-NP GBS (Extreme Light Infrastructure-Nuclear Physics Gamma Beam Source) is a high brightness elec-tron LINAC that is being built in Romania. The goal for this facility is to provide high luminosity gamma beam through Compton Backscattering. A train of 32 bunches at 100Hz with a nominal charge of 250pC is accelerated up to 740 MeV. Two interaction points with an IR Laser beam produces the gamma beam at different energies. In order to measure the electron beam spot size and the beam proper-ties along the train, the OTR screens must sustain the ther-mal and mechanical stress due to the energy deposited by the bunches. This paper is an ANSYS study of the issues due to the high quantity of energy transferred to the OTR screen. They will be shown different analysis, steady-state and thermal transient analysis, where the input loads will be the internal heat generation equivalent to the average power, deposited by the ELI-GBS beam in 512 ns, that is the train duration. Each analyses will be followed by the structural analysis to investigate the performance of the OTR materi

Thermal issues for the optical transition radiation screen for the ELI-NP compton gamma source

A high brightness electron LINAC is being built in the Compton Gamma Source at the ELI Nuclear Physics facility in Romania. To achieve the design luminosity, a train of 32 bunches, 16 ns spaced, with a nominal charge of 250 pC will collide with a laser beam in two interaction points. Electron beam spot size is measured with Optical Transition Radiation (OTR) profile monitors. In order to measure the beam properties, the OTR screens must sustain the thermal and mechanical stress due to the energy deposited by bunches. This paper is an ANSYS study of the issues due to the high energy transferred to the OTR screens. Thermal multicycle analysis will be shown; each analysis will be followed by a structural analysis in order to investigate the performance of the materia

Analysis and Correction of Geometrical Non-Linearities of ELI-NP BPMs on Position and Current Measurements

The advanced source of Gamma-ray photons will be soon built near Bucharest (Romania) by an European consortium (EurogammaS) led by INFN, as part of the ELI-NP (Extreme Light Infrastructure-Nuclear Physics). It will generate photons by Compton back-scattering in the collision between a multi-bunch electron beam, at a maximum energy of 720 MeV, and a high intensity recirculated laser pulse. An S-Band photo-injector and the following C-band Linac, which are under construction, will operate at 100Hz repetition rate with macro pulses of 32 electron bunches, separated by 16ns and with 250pC nominal charge. Stripline and cavity BPMs will be installed along the linac, in order to measure both the position and charge of the electron beam. Stripline BPM response can be considered linear within a limited area around the BPM origin. In order to use the full BPM acceptance area, without accuracy losses due to non-linearities, we plan to use correction algorithms, developed on the basis of simulations and measurements of BPMs response. In particular, suitable high-order surface polynomials will be used

Root internalization of Salmonella Typhimurium in basil plants

Abstract Background Foodborne pathogens present in soil or irrigation water have the potential to internalize via root into edible parts of the plants and survive, representing a serious hazard for consumer's health (1). The present work assesses the ability of Salmonella Typhimurium (ST) to enter basil plants (Ocimum basilicum L., cultivar "Napoletano") from roots. This situation may represent a risk in food safety since that vegetable is largely used raw/undercooked, in the Mediterranean diet. Methods Sixteen basil plants were cultivated in hydroponics, from the seeds. Roots from 14 plants at 4 leaves-stage were individually immersed in liquid media contaminated with a suspension of ST isolated from Aterno river in Abruzzo region, Italy (9 log10 cfu/mL final concentration). Two plants were used as negative controls (no ST challenge); surface swabs were taken from leaves and stems to exclude external contaminations. After 24 hours, plants were tested for detection (UNI EN ISO 6579-1:2017) and enumeration (in-house method) of ST in leaves and stems. Results ST detection gave positive results in 14/14 plants; in particular, ST was present in 14/14 plants in the leaves and for 9/14 plants also in the stems. The internalized ST strains were also enumerated in 10/14 plants. In particular, 3/14 plants gave positive results both in the leaves and stems, 2/14 only in the stems and other 5/14 only in the leaves. The average ST counts were of 4 log10 cfu/g in leaves and stems. All negative ctr/surface swabs were negative to ST. Conclusions Even though antimicrobial properties of basil plants have been described (2), this study demonstrated the potential of ST to internalize, survive and spread to edible parts. The findings highlight the risk of human infections by ST in plant following root uptake, suggesting the importance of applying appropriate preventive pre-harvest strategies. Biblio EFSA. E. Jour. (2014);12(3):3600 Tenore et al. (2017). Natural product research, 31(17), 2067-2071 Key messages The ability of Salmonella Typhimurium to internalize, survive and spread to edible parts of basil plants. Pathogenic bacteria root uptake represents a potential risk for human health

Conceptual design of electron beam diagnostics for high brightness plasma accelerator

A design study of the diagnostics of a high brightness linac, based on X-band structures, and a plasma accelerator stage, has been delivered in the framework of the EuPRAXIA@SPARC_LAB project. In this paper, we present a conceptual design of the proposed diagnostics, using state of the art systems and new and under development devices. Single shot measurements are preferable for plasma accelerated beams, including emittance, while $\mu$m level and fs scale beam size and bunch length respectively are requested. The needed to separate the driver pulse (both laser or beam) from the witness accelerated bunch imposes additional constrains for the diagnostics. We plan to use betatron radiation for the emittance measurement just at the end of the plasma booster, while other single-shot methods must be proven before to be implemented. Longitudinal measurements, being in any case not trivial for the fs level bunch length, seem to have already a wider range of possibilities

What should a quantitative model of masking look like and why would we want it?

Quantitative models of backward masking appeared almost as soon as computing technology was available to simulate them; and continued interest in masking has lead to the development of new models. Despite this long history, the impact of the models on the field has been limited because they have fundamental shortcomings. This paper discusses these shortcomings and outlines what future quantitative models should look like. It also discusses several issues about modeling and how a model could be used by researchers to better explore masking and other aspects of cognition