Bunch Size Research Articles

Analytical and numerical analysis of longitudinally coupled transverse dynamics of Pulse Picking by Resonant Excitation in storage rings serving timing and high-flux users simultaneously

Abstract The pulse picking by resonant excitation (PPRE) method is applied at BESSY II to provide single bunch light to timing users while operating a multi-bunch filling pattern. This method can provide single bunch light to all beamlines simultaneously since the emittance of a selected bunch is increased by a quasi-resonant incoherent excitation close to the first synchrotron sideband of the betatron oscillation frequency. This gives high-flux to users by separating the synchrotron radiation from one horizontally enlarged bunch from the light of the multi-bunch beam. The properties of the excited bunch depend strongly on lattice parameters such as beta-functions and horizontal chromaticity, and the frequency and amplitude of the excitation signal. A theoretical interpretation by applying a linear transfer-matrix analysis based on the Liouville’s theorem is derived to illustrate a quantitative relation between the beam size and lattice parameters. In addition, measurements and numerical simulations show a monotonic increase of the timing bunch emittance as a function of the excitation amplitude at the first synchrotron sideband of the betatron oscillation frequency. The observed excitation-amplitude-dependent features of the transverse bunch size are confirmed by measurements with two independent diagnostics at BESSY II.

Spontaneous Cyclotron Radiation of a Dense Electron Bunch

Short dense electron bunches generated by today’s photoinjectors [1–5] are advantageous for creating powerful sources of spontaneous coherent radiation in the terahertz frequency range. The regime of spontaneous radiation is achieved when the bunch size in the phase space is well below 2π. Coulomb interaction between particles in the dense bunches increases the axial size, and thus can limit the power and duration of radiation. It is shown this problem can be solved for cyclotron radiation by compensating for the Coulomb repulsion in the phase space.

Surgery or surgical defolation in ‘Grand Naine’ banana in the control of black Sigatoka in the state of Rio de Janeiro

Abstract ‘Grande Naine’ banana (Musa acuminata - AAA) in the municipality of Angra dos Reis (RJ) has been affected by the Black Sigatoka agent, fijiensis Mycosphaerella(current name Pseudocercospora fijiensis); causing losses to local producers, mostly small producers and low-income producers. Since Black Sigatoka was reported in the mentioned municipality, it was aimed to determine control efficiency through surgical measurement or surgical defoliation and to evaluate its effect on banana productivity characteristics. For this purpose, treatment was designed in the form of completely randomized blocks containing three blocks, each block with five plants with treatment (Surgery) and five plants without treatment (Control), in a total of 30 plants with fungal infection. Treatments were performed every 15 days with monthly severity assessments (Weighted Mean of Infection - MPI) by the method of Stover modified by Gauhl. The results obtained at the end of the trial showed significant differences in all variables (Severity, youngest leaf spotted, bunch weight and fruit size), and treatment with surgery provided reduction in severity (MPI) around 58%, thus confirming that plants received adequate treatment according to the results obtained for this methodology, and, contributing to the increase of the healthy leaf area in the youngest leaves, whereas in plants without surgery (Control), severity increased by 14.8% in comparison to the initial MPI evaluation, consequently having a smaller healthy leaf area for the accomplishment of photosynthesis and other physiological processes. In production variables bunch weight, fruit size and number of fruits, differences were significant (Pr> F = 0.0001), reaching an increase in yield of up to 300% when compared to Control. It is therefore an effective method for the control of phytopathogen black sigatoka unpublished in the state of Rio de Janeiro and that will bring direct benefits for Family Agriculture in the region of incidence of this banana disease.

Bidirectional Soliton Rain Dynamics Induced by Casimir-Like Interactions in a Graphene Mode-Locked Fiber Laser.

We study experimentally and theoretically the interactions among ultrashort optical pulses in the soliton rain multiple-pulse dynamics of a fiber laser. The laser is mode locked by a graphene saturable absorber fabricated using the mechanical transfer technique. Dissipative optical solitons aggregate into pulse bunches that exhibit complex behavior, which includes acceleration and bidirectional motion in the moving reference frame. The drift speed and direction depend on the bunch size and relative location in the cavity, punctuated by abrupt changes under bunch collisions. We model the main effects using the recently proposed noise-mediated pulse interaction mechanism, and obtain a good agreement with experiments. This highlights the major role of long-range Casimir-like interactions over dynamical pattern formations within ultrafast lasers.

Development of the Electron-Beam Diagnostics for the Future BESSY-VSR Storage Ring

This contribution focusses on the different types of new or improved electron-beam monitors at BESSY II for bunch resolved measurements under future BESSY-VSR conditions. A new diagnostics platform, involving three different dipole beam lines will be built for different dipole-related optical and THz methods. Our main concepts for robust future monitors for bunch length, beam size and position are presented in the following.

Longitudinal Bunch Size Measurements with an RF Deflector at J-PARC LINAC

We have measured the longitudinal bunch size of beams from the radio-frequency quadrupole linac (RFQ) at the Japan Proton Accelerator Research Complex (J-PARC). The radio-frequency deflector (RFD) is installed in the medium-energy beam transport section (MEBT1) between the RFQ and the drift-tube linac (DTL). The RFD, which is usually used to produce a macro pulse configuration for the 3-GeV rapid-cycling synchrotron, is utilized to produce a different deflecting angle depending on the bunch arrival phase. Transverse beam profiles were measured after the RFD with and without deflection to extract the longitudinal bunch size. The Courant-Snyder parameters in the longitudinal direction were estimated by measurements for different strength of the upstream buncher. These measurements are one of the important steps to understand the longitudinal beam properties at a high beam current.

Longitudinal bunch size measurement using an RF deflector

It is extremely important to diagnose beams in accelerators to improve accelerator operation. In the low velocity section of a proton or heavy ion linac, the diagnostic method for longitudinal beam properties is less established compared to that for transverse properties. We have developed a new diagnostic method for the longitudinal bunch size by utilizing an RF deflector. We evaluated the uncertainty in bunch size measurement through simulation, and it was obtained as 0.5°. In addition, we measured longitudinal beam emittance through bunch size measurements at several RF amplitudes of an upstream buncher. The measured emittance was 0.13±0.01π deg.MeV, which was consistent with the simulation result.

Assessment of ‘hen and chicken’ disorder for marketable yield estimates of table grape using the ‘Berry Analysis Tool’

Bunch and berry size are important quality criteria for table grapes, and bunch weight is used in estimation of vine yield. The Berry Analysis Tool (BAT), a machine vision technique, was trialled for use in estimation of berry count, diameter and weight, to support estimates of ‘hen and chicken’ disorder and vineyard yield. Berries were spread on a plate for imaging. BAT estimates achieved a r2 = 0.99 on berry number per bunch, r2 = 0.98 on average berry minor axis and r2 = 0.99 on bunch weight. Based on an allometric relationship between lineal dimensions and weight, these attributes were used to estimate the proportion of under-size (‘chicken’) berries per bunch, and bunch weight. The estimated bunch weight multiplied by a number bunches per vine provides an estimation of vine yield. Use of the BAT as a decision support tool in table grape farm management is described.

MITHRA 1.0: A full-wave simulation tool for free electron lasers

Free Electron Lasers (FELs) are a solution for providing intense, coherent and bright radiation in the hard X-ray regime. Due to the low wall-plug efficiency of FEL facilities, it is crucial and additionally very useful to develop complete and accurate simulation tools for better optimizing a FEL interaction. The highly sophisticated dynamics involved in a FEL process was the main obstacle hindering the development of general simulation tools for this problem. We present a numerical algorithm based on finite difference time domain/Particle in cell (FDTD/PIC) in a Lorentz boosted coordinate system which is able to fulfill a full-wave simulation of a FEL process. The developed software offers a suitable tool for the analysis of FEL interactions without considering any of the usual approximations. A coordinate transformation to bunch rest frame makes the very different length scales of bunch size, optical wavelengths and the undulator period transform to values with the same order. Consequently, FDTD/PIC simulations in conjunction with efficient parallelization techniques make the full-wave simulation feasible using the available computational resources. Several examples of free electron lasers are analyzed using the developed software, the results are benchmarked based on standard FEL codes and discussed in detail. Program summaryProgram Title: MITHRAProgram Files doi:http://dx.doi.org/10.17632/9f5k4zbtkg.1Licensing provisions: GNU General Public License 3Programming language: C++Nature of problem: Full-wave simulation of the free electron laser radiation is accomplished by the code. MITHRA transforms the particle positions and momenta to the bunch rest frame using the Lorentz transformation. Electrons entering the undulator start radiating due to the induced wiggling motion. The back-effect of the radiation on the bunch results in the modulation of the electron position, which in turn generates a coherent radiation. This process as the main principle behind the operation of free electron lasers is simulated using Maxwell equations, electron motion equations and relativity principles.Solution method: Non-standard Finite Difference Time Domain (NSFDTD) combined with Particle-in-Cell (PIC) is implemented in the Lorentz-boosted framework to calculate the FEL radiation. Parallelization is done using both multi-threading (open-MP) and message passing interface (MPI) to maximize the computation efficiency.

Effect of pieces size of Empty Fruit Bunches (EFB) on composting of EFB mixed with activated liquid organic fertilizer

This research was to determine the effect of pieces sizes of oil palm empty fruit bunch (EFB) on the composting of EFB mixed with activated liquid organic fertilizer (ALOF) in a basket composter in order to obtain high quality compost. The composting process was started by cutting the EFB into pieces with varies sizes, inserting the EFB pieces into basket composter (33 cm W × 28 cm L × 40 cm H), and adding ALOF until moisture content (MC) in the range of 55-65%. During composting, the compost pile was turned every 3 days and the MC was maintained at 55-65% range by adding the ALOF. The sizes of the EFB pieces were varied into <1, 1-3, 4-7, 8-11, and 12-15 cm. The parameters analysed during the composting were temperature, pH, MC, compost weight, water holding capacity (WHC), CN ratio, and the quality of the final compost. Composting was carried out for 40 days and the best result obtained at EFB pieces size was 1-3 cm with compost characteristic were pH 9.0; MC 52.59%; WHC 76%; CN ratio 12.15; N 1.96%; P 0.58%; and K 0. 95%.

Variability assessment in Phoenix dactylifera L. accessions based on morphological parameters and analytical methods

Phoenix dactylifera L., usually identified as the Date Palm, is defined as a palm tree in the genus Phoenix, known for its comestible crop. To facilitate characterization of date-palm germplasm, a model based on morphological parameters has been designed to explain the effect of these descriptors on development of different date-palm accessions located in the Tunisian eco-geographical environment. In our study, we relate the phenotypic differences and connections in a collection of 69 various date-palm accessions as showed by vegetative factors. Furthermore, we apply morphological markers to describe date-palm ecotypes. Morphological and phenotypical characteristics depicting the vegetative models were estimated. The measured data set was treated using principal components analysis and principal coordinate analysis clustering. The principal component analysis indicated that the first two principal components represented 39% of the totality of variation. Indeed, the Principal coordinate analysis plot demonstrated that first three coordinates explained more than 43% of the total variance. Obtained results showed that shaft length increased with spine length and stipe size has inverse relationship with crown shape. Besides, spine rigidity has a growing relationship with leaflet width and palm bunch size has an increasing relationship with both leaflet length and leaf palm length. In addition, Bayesian networks gave an explicit model describing the different relationships between fruit and kernel characteristics. Decision-tree technique demonstrated that fruit and kernel characteristics (fruit and kernel weights, fruit and kernel lengths, fruit and kernel widths) were indispensable for model interpretation and thus palm-date yield prediction. This study supplies a simple classification plan and comprehensible analytical devices for recognizing the most important elements combined that may be practical to develop programs for date collect management.

Step Bunching Induced by Immobile Impurities in a Surface Diffusion Field

It is well known that impurities attached to a surface cause step bunching, but the effects of a surface diffusion field on step bunching have not been studied sufficiently. In this paper, we carry out Monte Carlo simulations using a simple lattice model and study how the surface diffusion field affects the growth law of the bunch size in the step bunching induced by immobile impurities. We consider a vicinal face with step spacing l. Both impurities and atoms impinge from a vapor phase to the vicinal face, but they do not evaporate. We change the impingement rate of atoms, F, keeping the ratio of the impingement rate of impurities to F constant. When F is smaller than a critical value Fc, the vicinal face becomes unstable and an array of equidistant bunches is formed. In the case of diffusion-limited growth, Fc is inversely proportional to l2. The dependence of Fc on l changes in the case of step-kinetics-limited growth: Fc becomes inversely proportional to l.

English

Diverse cultural practices have been communicated to and/or applied by resource-poor households over the past two decades to improve the overall farm health and crop tolerance to biotic/abiotic factors. This study assessed the current diversity and use of cultural practices on banana fields in Ituri and North Kivu provinces, eastern Democratic Republic of Congo (DR Congo). Interview schedules coupled with farm diagnosis were used to take stock of cultural practices. Farmers&rsquo; choice of banana cultivars was mainly influenced by bunch size, demand/price, pulp flavor/taste, and juice quality. Availability of planting materials and the lifespan of mats were also important. In contrast, drought tolerance, soil fertility conditions, length of production cycle, and pest and disease resistance were not highly considered. Suckers were the predominant type of planting material used. Banana-bean (in 15 to 39% of farms) and banana-taro-bean (18 to 30%) were the dominant intercrops. Staking of banana plants with bunches was applied by 94 to 95% of the respondents, possibly due to the perceived immediate benefits from bunches. Cutting of green leaves to among other things improve sunlight penetration for legume intercrops which was practiced by 74 to 85% of the farmers. This practice has greatly contributed to the perpetuation of banana Xanthomonas wilt disease (XW) in the region. Male bud removal was applied in 55 to 66% of farms to control XW and improve bunch size. However, 38 to 51% of these farmers de-budded after the recommended time. Other common cultural practices included de-suckering, pseudostem use for mulch and weeding. Strategies for safe application of some of the practices such as weeding, leaf cutting, de-trashing and in light of diseases such as XW are recommended. In addition, some practices such as mulching and male bud removal are knowledge intensive, while others such de-suckering have no immediate perceived benefits to farmers, thus the need to strengthen knowledge extension to enhance their adoption. &nbsp; Key words: Cropping, cultivars, cultural practices, de-budding, de-leafing, de-suckering. &nbsp

The Effect of Fertilisation on the Performance of Barlinka Table Grapes on Sandy Soil, Hex River Valley

The response of Barlinka table grapes on grayish, sandy soil to irrigation-applied N fertilisation levels, patterns of N application, crop load and stock P and K fertilisation, were evaluated over a 12-year period in the Hex River Valley. Under the conditions of the trial, an N level of about 100 kg ha-1 appeared to be optimum for shoot growth and grape quality. Bunch and crop mass benefited from increased N levels, apparently due to better berry set. Increased N levels also appeared to preserve greenness of bunch stems better during cold storage but N levels higher than 105-120 kg ha-' reduced colour and sugar content of berries. Applying 67% of total seasonal N during the pre-bloom to veraison period and the rest after harvest, as against a 50:50 distribution, had a slight, positive effect on shoot growth and bunch size, again apparently caused by better berry set. Indications of a small, positive response of shoot growth to stock P fertilisation were obtained. Potassium applied in this manner was found to be ineffective due to leaching and regular irrigation-applied K fertilisation had to be adopted. Increased crop load had a marked negative effect on shoot growth and grape quality, in the latter case comparable in magnitude to that of too high N levels. A balanced crop load of 22 bunches per vine with a shoot mass of 1,822 kg, was calculated for this trial, but a crop load of 18-19 bunches per vine appeared to be the maximum that still ensured the best quality.

Adıyaman Merkez İlçede Yetiştirilen Yerel Üzüm Çeşitlerinin Ampelografik Tanımlanması

In order to determine the ampelographic characters of grape cultivars grown in Adıyaman province, this research was carried out during 2014 and 2015. Ampelographic characters of varieties were identified according to “Grape Descriptors” of IBPGR (International Board for Plant Genetic Resources). In the 19 grape varieties grown in Adıyaman province belonging to species of Vitis vinifera L., berry skin colour was identified as ‘green yellow’ in 12 varieties, ‘dark red-black’ in 5 varieties, and ‘red’ in Kırmızı Sofralık and Sorik variety. The varieties had averagely 118.6-291.78 cm² bunch size, 123.09-710.91 g bunch weight, 2.05-6.21 g berry weight, 4.10-7.84 kg yield per vine, 10.5-26.0% soluble solids content and 3.29-4.46 g L -1 titretable acidity. In addition, flower type was ‘hermaphrodite’ in 16 varieties, ‘female with reflexed stamens’ in Zerik, Hönüsü and Bozgolik varieties.

ABA and GA3 regulate the synthesis of primary and secondary metabolites related to alleviation from biotic and abiotic stresses in grapevine

Plants are able to synthesize a large number of organic compounds. Among them, primary metabolites are known to participate in plant growth and development, whereas secondary metabolites are mostly involved in defense and other facultative processes. In grapevine, one of the major fruit crops in the world, secondary metabolites, mainly polyphenols, are of great interest for the wine industry. Even though there is an extensive literature on the content and profile of those compounds in berries, scarce or no information is available regarding polyphenols in other organs. In addition, little is known about the effect of plant growth regulators (PGRs), ABA and GA3 (extensively used in table grapes) on the synthesis of primary and secondary metabolites in wine grapes. In table grapes, cultural practices include the use of GA3 sprays shortly before veraison, to increase berry and bunch size, and sugar content in fruits. Meanwhile, ABA applications to the berries on pre-veraison improve the skin coloring and sugar accumulation, anticipating the onset of veraison.Accordingly, the aim of this study was to assess and characterize primary and secondary metabolites in leaves, berries and roots of grapevine plants cv. Malbec at veraison, and changes in compositions after ABA and GA3 aerial sprayings. Metabolic profiling was conducted using GC-MS, GC-FID and HPLC-MWD. A large set of metabolites was identified: sugars, alditols, organic acids, amino acids, polyphenols (flavonoids and non-flavonoids) and terpenes (mono-, sesqui-, di- and triterpenes). The obtained results showed that ABA applications elicited synthesis of mono- and sesquiterpenes in all assessed tissues, as well as L-proline, acidic amino acids and anthocyanins in leaves. Additionally, applications with GA3 elicited synthesis of L-proline in berries, and mono- and sesquiterpenes in all the tissues. However, treatment with GA3 seemed to block polyphenol synthesis, mainly in berries. In conclusion, ABA and GA3 applications to grapevine plants cv. Malbec influenced the synthesis of primary and secondary metabolites known to be essential for coping with biotic and abiotic stresses.

A new station for optical observation of electron beam parameters at electron storage ring SIBERIA-2

A new station for optical observation of electron beam parameters at the electron storage ring SIBERIA-2 is dedicated for measurement of the transverse and longitudinal size of electron bunches with the use of the synchrotron radiation (SR) visible spectrum in single-bunch and multi-bunch modes and for study of time-dependent behavior of individual electron bunches with changing accelerator parameters. The article briefly describes the main components of the diagnostics and the experimental results.

Step bunching and macrostep formation in 1D atomistic scale model of unstable vicinal crystal growth

We devise a new 1D atomistic scale model of vicinal growth based on Cellular Automaton. In it the step motion is realized by executing the automaton rule prescribing how adatoms incorporate into the vicinal crystal. Time increases after each rule execution and then nDS diffusional updates of the adatoms are performed. The increase of nDS switches between the diffusion-limited (DL, nDS=1) and kinetics-limited (KL, nDS>>1) regimes of growth. We study the unstable step motion by employing two alternative sources of instability – biased diffusion and infinite inverse Ehrlich-Schwoebel barrier (iiSE). The resulting step bunches consist of steps but also of macrosteps since there is no step-step repulsion incorporated explicitly into the model. This complex pattern formation is quantified by studying the time evolution of the bunch size N and macrostep size Nm in order to find the proper parameter combinations that rescale the time and thus to obtain the full time-scaling relations including the pre-factors. For the case of biased diffusion the time-scaling exponent β of N is 1/2 while for the case of iiSE it is 1/3. In both cases, the time-scaling exponent βm of Nm is ~3β/4 in the DL regime and 3β/5 in the KL one.

Proton driven plasma wakefield generation in a parabolic plasma channel

An analytical model for the interaction of charged particle beams and plasma for a wakefield generation in a parabolic plasma channel is presented. In the suggested model, the plasma density profile has a minimum value on the propagation axis. A Gaussian proton beam is employed to excite the plasma wakefield in the channel. While previous works investigated on the simulation results and on the perturbation techniques in case of laser wakefield accelerations for a parabolic channel, we have carried out an analytical model and solved the accelerating field equation for proton beam in a parabolic plasma channel. The solution is expressed by Whittaker (hypergeometric) functions. Effects of plasma channel radius, proton bunch parameters and plasma parameters on the accelerating processes of proton driven plasma wakefield acceleration are studied. Results show that the higher accelerating fields could be generated in the PWFA scheme with modest reductions in the bunch size. Also, the modest increment in plasma channel radius is needed to obtain maximum accelerating gradient. In addition, the simulations of longitudinal and total radial wakefield in parabolic plasma channel are presented using LCODE. It is observed that the longitudinal wakefield generated by the bunch decreases with the distance behind the bunch while total radial wakefield increases with the distance behind the bunch.

Reducing the Sugar and pH of the Grape (Vitis vinifera L. cvs. ‘Grenache’ and ‘Tempranillo’) Through a Single Shoot Trimming

Many vineyards all over the world can easily produce high potential alcohol levels, but the importance of the sugar content in berries has been changing over the past few years. The objective of this work was to reduce the sugar and pH of the grapes, delay berry ripening by decreasing the ratio between the leaf area and yield, perform an intense trimming treatment after berry set and establish the consequences for grapevine productivity in the following year. Severe shoot trimming was done over a three-year period (2010 to 2012). Phenological, vegetative and productive parameters were examined. The date of veraison was delayed by about 20 days. On the same harvesting date, the trim treatment had lower soluble solids (12% to 15 % reduction), lower pH (0.1 to 0.3) and a lower total anthocyanin content (10% reduction). The trim effect was also reflected in berry weight; as a consequence, bunch size and yield were also reduced by around 10%. If the trim treatment does not reduce the leaf area to fruit ratio below 0.50 m2/kg, there is no negative impact on vine capacity in the next year.