Polarized Negative Ion Source with Multiply Sphericaly Focusing Surface Plasma Ionizer

It is proposed one universal H-/D- ion source design combining the most advanced developments in the field of polarized ion sources to provide high-current high-brightness ion beams with >90% polarization and improved lifetime, reliability, and power efficiency. The new source utilizes high-efficiency resonant charge-exchange ionization of polarized neutral atoms by negative ions generated by cesiated surface-plasma interactions via a multi-spherical negative ion focusing element. Multi-spherical focusing of the negative ions strongly suppresses the parasitic generation of unpolarized H-/D- ions. By incorporating new and novel designs for the dissociator and plasma generator in parallel with the multi-spherical focusing the design can suppress adsorption and depolarization of particles from the polarized beam greatly improving performance over current concepts

30 Years of High-Intensity Negative Ion Sources for Accelerators

Thirty years ago, July 1, 1971, significant enhancement of negative ion emission from a gas discharge following an admixture of cesium was observed for the first time. This observation became the basis for the development of Surface Plasma Sources (SPS) for efficient production of negative ions from the interaction of plasma particles with electrodes on which adsorbed cesium reduced the surface work-function. The emission current density of negative ions increased rapidly from j {approximately} 10 mA/cm{sup 2} to 3.7 A/cm{sup 2} with a flat cathode and up to 8 A/cm{sup 2} with an optimized geometrical focusing in the long pulse SPS, and to 0.3 A/cm{sup 2} for DC SPS, recently increased up to 0.7 A/cm{sup 2}. Discovery of charge-exchange cooling helped decrease the negative ion temperature T below 1 eV, and increase brightness by many orders to a level compatible with the best proton sources, B = j/T> 1 A/cm{sup 2} eV. The combination of the SPS with charge-exchange injection improved large accelerators operation and has permitted beam accumulation up to space-charge limit and overcome this limit several times. The early SPS for accelerators have been in operation without modification for {approximately} 25 years. Advanced version of the SPS for accelerators is described. Features of negative ion beam formation, transportation, space-charge neutralization-overneutralization, and instability damping is considered. Practical aspects of SPS operation and high brightness beam production is discussed

Дослідження основних параметрів технологічного процесу електроконтактного приварювання при відновленні деталей машин

The object of research is the process of restoring lancet cultivator paws by electrocontact welding of their working parts, the process connection with technological processing parameters and the physical and mechanical properties of their material.One of the most problematic places in the method of electrocontact welding when restoring the working organs of tillage machines is the lack of optimal operating parameters of this technological process of strengthening the cutting elements of working organs working in the soil-aggressive environment.Optimal parameters of electrocontact welding method of the metal mesh to the worn-out surface of the part make it possible to increase the strength of the material of the recovered parts, improve its physical and mechanical properties and increase their service life, and to reduce the magnitude and irregularity of wear.Theoretical studies of the main parameters of the technological process are carried out using the equations of mechanics of deformed bodies with their own physical and mechanical properties.In the course of the study, a steel mesh made of high-strength steel is used, and metal powders are used as a filler material, which strengthened the material of the component and increased its life.Increased wear resistance of the restored parts is obtained. This is due to the fact that with this technological process, the formation of the surface relief takes place with the formation of depressions on it, which retain the lubricant, which ensures a higher coating resistance.Due to this, it is possible to obtain a coating of parts with a thickness of up to 1.5 mm, an increase in their durability of 1.45–2.1 times and a decrease in wear intensity of 1.65 times compared to new cultivator paws.Приведены результаты исследования условий работы деталей машин, выявлены причины снижения их ресурса, дан анализ методов восстановления их работоспособности. Предложен технологический процесс повышения их долговечности применением более эффективного метода восстановления электроконтактным привариванием. Определены значения основных параметров предложенной технологии.Приведені результати досліджень умов роботи деталей машин, виявлені причини зниження їх ресурсу, поданий аналіз методів відновлення їх працездатності. Запропонований технологічний процес підвищення їх довговічності використанням більш ефективного методу відновлення електроконтактним приварюванням. Знайдені значення основних параметрів запропонованої технології

Some Features of Transverse Instability of Partly Compensated Proton Beams

suppression of generation and accumulation of secondary particles is a traditional method for suppression the transverse electron-proton instability: improve the vacuum, use a gap in beam for electron removing, use cleaning electrodes, suppressing secondary emission. But opposite solution is also possible. Transverse e-p instability in proton rings can be damped by increasing beam density and the rate of secondary particles generation above a threshold level, with decrease of the unstable wavelength below a transverse beam size. In high current Proton Storage Rings (PSR) such as, the LANSCE PSR it is possible to reach this island of stability by multiturn, concentrated charge exchange injection without painting and by enhanced generation of secondary plasma. This possibility was demonstrated in smaller scale PSR at the INP, Novosibirisk [1]. Damping of the e-p instability allowed to accumulate a coasting, space charge compensated, circulating proton beam with intensity, corresponding to the Laslett tune shift of {Delta}{nu} = 5 in the ring with original tune of {nu} = 0.85. In the other PSR transverse instability of bunched beam was damped by a simple feed back [2,3]. In this article they discuss experimental observations of transverse instability of proton beams in different accelerators and storage rings and consider methods to damp the instability. The presented experimental dates could be useful for verification of computer simulation tools developed for investigation of space charge effects and beam instabilities in realistic conditions [4,5]

Hamiltonian structures for general PDEs

We sketch out a new geometric framework to construct Hamiltonian operators for generic, non-evolutionary partial differential equations. Examples on how the formalism works are provided for the KdV equation, Camassa-Holm equation, and Kupershmidt's deformation of a bi-Hamiltonian system.Comment: 12 pages; v2, v3: minor correction