ACCELERATING OF THE ELECTRONS OF ELECTRON BUNCHES IN A WAVEGUIDE LOADED DIELECTRIC STRUCTURE

The paper presents some results of experimental studies of the excitation of wake fields and the acceleration of electrons in waveguide-dielectric structures (DS) upon injection of a sequence of electron bunches into them. Exper-iments have shown an increase in the amplitude of the wake wave and the acceleration of a small fraction of elec-trons when the wavelength of the excited field is equal to the doubled bunch length. A simple physical model of the observed phenomenon is given. Also, the paper proposes a method for accelerating a part of each electron bunch in the steady-state mode of the resonator dielectric structure. Some of the electrons are “cut out” by the collimator and enter the accelerating phase of the previously excited wake wave. The wave is displaced due to the difference in the distances traveled by the wave and the accelerated part of the electrons.

Longitudinal Beam Dynamics for the Heavy-Ion Synchrotron Booster Ring at HIAF

To accelerate high-intensity heavy-ion beams to high energy in the booster ring (BRing) at the High-Intensity Heavy-Ion Accelerator Facility (HIAF) project, we take the typical reference particle 238U35+, which can be accelerated from an injection energy of 17 MeV/u to the maximal extraction energy of 830 MeV/u, as an example to study the basic processes of longitudinal beam dynamics, including beam capture, acceleration, and bunch merging. The voltage amplitude, the synchronous phase, and the frequency program of the RF system during the operational cycle were given, and the beam properties such as bunch length, momentum spread, longitudinal beam emittance, and beam loss were derived, firstly. Then, the beam properties under different voltage amplitude and synchronous phase errors were also studied, and the results were compared with the cases without any errors. Next, the beam properties with the injection energy fluctuation were also studied. The tolerances of the RF errors and injection energy fluctuation were dictated based on the CISP simulations. Finally, the effect of space charge at the low injection energy with different beam intensities on longitudinal emittance and beam loss was evaluated.

Quality Responses of Table Grapes ‘Flame Seedless’ as Effected by Foliarly Applied Micronutrients

Micronutrient (iron, zinc and boron) deficiencies are a basic and prominent factor affecting grape quality and yield in the Pothwar region. To overcome these deficiencies, different levels of micronutrients were applied foliarly on grapevines at five different berry developmental stages during two consecutive growing seasons (2018 and 2019). The data suggested that foliar treatment of micronutrients significantly increased the yield, number of bunches per vine, bunch weight, yield per vines, bunch length, berry number per cluster, berry diameter, berry weight and cluster compactness. The biochemical quality attributes of berries, including sugars (reducing, non-reducing as well as total sugars), ascorbic acid content, pH and TSS values, were at their highest levels in grapevines supplemented with Fe, Zn and B treatment at 200 ppm, respectively, i.e., the highest concentrations used. Biochemical leaf values, including chlorophyll a and b and leaf micronutrient content (Fe, Zn and B), were also highest in grapevines that were sprayed with Fe, Zn and B at 200 ppm. Overall, the results revealed that the performance of grapevine cv. ‘Flame Seedless’ growing in agroclimatic conditions of the Pothwar region was improved as a result of the foliar application of Fe, Zn and B at 200 ppm. The results also suggested that a further increase in the concentration of each nutrient might be helpful to obtain berries of improved quantity and quality.

Monitoring the size of low-intensity beams at plasma-wakefield accelerators using high-resolution interferometry

Plasma-based accelerators are on the brink of a development stage, where applications of the beam for medical sciences, imaging, or as an injector for a future large-scale accelerator-driven light source become feasible. The requirements on electron beams for injection into a storage-ring are stringent regarding beam quality and reliability. Here, we propose a beam diagnostic technique for measuring lateral beam sizes with a few-μm resolution by applying a state-of-art single-photon camera to coherent synchrotron radiation that affords by a sub-femtosecond short bunch-length property. A sophisticated image processing algorithm enables the technique down to 5 photons/pixel for the visibility of 0.132. Results show the potential of the proposed system that achieves precise retrieval of the complex degree of coherence at an extremely low photon intensity similar to those expected towards the plasma-acceleration injectors.

Morpho-phenological characterization of grape (Vitis vinifera L.) germplasm grown in northern zones of Punjab, Pakistan

This endeavor includes thirty grapes’ genotypes grown in northern zones of Punjab, Pakistan to determine similarities and dissimilarities in forty-four morphological traits according to the descriptor “International Plant Genetic Resources Institute (IPGRI)”. The relation between the genotypes was determined by principal component analysis (PCA), and similarity was worked out by using cluster analysis. The dendrogram divided the genotypes into two main groups with classes and subclasses. The variation present within the class was up to 81.72% while the difference between classes was 18.28%. The morphological quantitative traits such as bunch length, bunch width, bunch weight, peduncle length, the weight of 10 berries, number of berry in a bunch, berry length, and berry width were in the following range 27.50-11 cm, 13.75-5 cm, 583.56-77.70 g, 6.50-1.55 cm, 53.70-9.70 g, 354-28, 27.37-11.40 mm and 18.06-10.41 mm respectively, which indicated a wide level of diversity in the selected genotypes. Based on phenological attributes, “Regina”, “Perlet”, and “Early White” were found early maturing genotypes to prevent berry rotting due to monsoon rains at the final stage of ripening. The data generated in this study would be helpful to preserve the existing germplasm and be available for designing future breeding programs.

Épocas de desponte de cachos na variedade de uva rainha Itália (Vitis vinifera L.), produzida em ambiente protegido na Serra Gaúcha

The objective of the work was to evaluate the production and quality of the cultivar Italia produced in a protected environment, submitted to three seasons of topping of bunch. The experiment was carried out in 2015, in Caxias do Sul - RS. The experimental design used blocks at random with four treatments, being: without topping of bunch, topping of bunch in pre-flowering, topping of bunch in full bloom, topping of bunch in post-blooming. The variables analyzed were: production per plant, bunch weight, bunch length, berry diameter and number of bunches soluble solids and titratable acidity. Regardless of the pruning time of the bunches, the factors of production and the evaluated chemical physics were not affected, obtaining bunches with weight and shape according to market requirements.