Theory Of Accelerators Research Articles

Involving the new generations in particle physics endeavours

Since 1984 INFN and University of Pisa scientists performing experiments at Fermilab have been running a two-month summer training program for Italian students at the lab. In 1984 the program involved only a few physics students from the University of Pisa, but it was later extended to other INFN groups and to engineering students. Since 2004 the program has been supported in part by the US Department of Energy (DOE) in the frame of an exchange agreement with INFN and has been run by the Cultural Association of Italians at Fermilab (CAIF). In 2007 the Sant’Anna School of Advanced Studies (Pisa) established an agreement with Fermilab to share the cost of four engineering students each year. In the almost 40 years of its history, the program has hosted at Fermilab approximately 550 Italian students from more than 20 Italian universities and from some non-Italian universities. In addition, in the years 2010-2019, with the support of the Italian National Institute of Astrophyics (INAF), the Italian Space Agency (ASI), and CAIF, 30 students were hosted in other US laboratories and universities. The Fermilab training programs spanned from data analysis to design and construction of particle detectors and accelerator components, R/D on superconductive elements, theory of accelerators, and analysis of astrophysical data. At the other US laboratories the offered training was on Space Science. In 2015 the University of Pisa endorsed the program as one of its own Summer Schools. The interns are enrolled as Pisa students for the duration of the internship. They are required to write summary reports published in the Fermilab and University of Pisa web pages. Upon positive evaluation by a University board, students are acknowledged 6 ECTS credits. The entire program is expected to expand further under CAIF management. An agreement has been signed between ASI and CAIF, for ASI to support yearly three two-months fellowships in US space science. In the following we inform on student recruiting, training programs, and final evaluation

The problem of insulin resistance in children with type 1 diabetes. Рart 1

Currently the incidence and prevalence of type 1 diabetes in children increase. The cause of this phenomenon is not only genetic factors. The theory of accelerators is considered to be one of the possible explanations. Accelerators are factors that shift the manifestation of type 1 diabetes to an earlier age. There are two accelerators of autoimmune destruction of β­cells: insulin resistance associated with overweight and genetic predisposition. The prevalence of overweight and obesity in children with newly diagnosed diabetes mellitus increased threefold between 1979—1989 and 1990—1998. It is suggested that currently diabetes develops in children with moderate genetic predisposition more often due to increasing prevalence of overweight in the population. According to a number of studies, the prevalence of overweight and obesity in children with type 1 diabetes is higher than in general population. High doses of insulin are found to be associated with overweight and increased risk of longterm complications of diabetes. Risk factors of reduced insulin sensitivity include long diabetes experience, puberty, relatives with obesity or type 2 diabetes, sedentary lifestyle, diet with protein and fat excess. Currently, there is much data regarding the role of insulin therapy in the pathogenesis of insulin resistance in type 1 diabetes: the mismatch of treatment to the physiological profile of hormone secretion in the body and iatrogenic «hyperinsulinization». Modification of lifestyle and nutrition, as well as the development of new technologies for the treatment of diabetes gives allow for expectation of insulin sensitivity improvement in patients with type 1 diabetes.

WHY DOES THE STRUGGLE AROUND SRT CONTINUE TO THIS DAY?

The purpose of this article is not to criticize the theory of relativity, but to try to understand why, despite more than a century of dominance in physics, it is constantly criticized by physicists. In this paper, a thorough analysis of A. Einstein's theory of relativity is carried out. It relies on philosophical, physical-mathematical, logical-historical methods of investigation. It is shown that in SRT there is an error in the physical interpretation of the mathematical formalism of the Lorentz transformation (epistemological error). Therefore, the interpretation of the SRT phenomena contains logical contradictions and paradoxes. It is also shown that a consistent interpretation can be given for the Lorentz transformation within the framework of classical space-time representations. It is established that the real speed of the relative motion of inertial reference frames in is greater than the speed entering the Lorentz transformation. A new explanation is offered for relativistic phenomena without violating logic and without paradoxes. The results are of great importance for the description of relativistic phenomena in physical theories, and also for applied disciplines, for example, for the theory of cyclic accelerators, etc.

O.I. Akhiezer Institute of Theoretical Physics

Professor A.I. Akhiezer is an outstanding Soviet theoretical physicist who made an outstanding contribution to the development of science. He is one of the most active in the field of theoretical physics of Soviet scientists. He has done about a hundred papers on various problems of nuclear physics, quantum electrodynamics, and the theory of charged particle accelerators. A number of difficult and ingenious studies, which gave fundamental results, made a significant contribution to the development of these problems and made his name known and authoritative among scientists of the Soviet Union and abroad. Professor A.I. Akhiezer is one of the best Soviet theoretical physicists working in the field of atomic nucleus physics and quantum electrodynamics. He is the author of first-class works on the scattering of γ-quanta by nuclei, on the diffraction scattering of nuclear particles. He established the possibility of a new phenomenon — diffraction splitting of deuterons by nuclei. AI Akhiezer is the author of the pioneering work on the scattering of neutrons in crystals, which have become particularly important in connection with the question of the moderation of neutrons. Of great importance was his first work to determine the critical dimensions of the reactor, taking into account the slowing down of neutrons. Of particular note are the works of Professor A.I. Akhiezer and his school on the theory of linear accelerators of charged particles and the theory of plasma.

A primer on theory and operation of linear accelerators in radiation therapy

A primer on theory and operation of linear accelerators in radiation therapy

On the magnetohydrodynamics flows in curved coaxial channels

Stationary plasma flows obtained by using numerical solutions of corresponding stationary problems in curved coaxial channels are considered. It is supposed that plasma interacts with own azimuthal magnetic field. The main attention of the paper is focused on accelerating transonic flows, which attract a considerable interest in the theory of plasma accelerators. It was demonstrated that a curvilinear configuration of a channel makes the significant contribution to distributions of basic plasma parameters.

A theory of ferromagnetic waveguide accelerators driven by an electron beam

A fully self-consistent theory of ferromagnetic waveguide accelerators driven by a relativistic electron beam is developed. The theoretical analysis is based on Faraday’s law, which provides a second-order partial-differential equation of the azimuthal magnetic field, under the assumption that με≫1. Here μ and ε are the permeability and dielectric constant of the waveguide material. The azimuthal magnetic field and axial acceleration field are obtained in forms of integral equations for an arbitrary profile of the drive-beam current I(t). In the limit when the conductivity σ of the waveguide material is zero, the acceleration mechanism is similar to the typical wake-field accelerators. In this limit, the acceleration field is proportional to the square root of the parameter μ/ε and can be easily more than 200 MV/m for moderate system parameters. On the other hand, for high conductivity limit, the acceleration mechanism is the magnetic field decay, exhibiting that the electromagnetic fields are a decaying function of the time. With appropriate physical parameters, the acceleration gradient of the magnetic field-decay accelerator is also very large.

A Primer on Theory and Operation of Linear Accelerators in Radiation Therapy by C. J. Karzmark and R. J. Morton

<i>A Primer on Theory and Operation of Linear Accelerators in Radiation Therapy</i> by C. J. Karzmark and R. J. Morton

Линейные индукционные ускорители — новые генераторы мощных пучков релятивистских электронов

Electrophysical Apparatus, Leningrad). Usp. Fiz. Nauk; 110: No. 1, 117-137(May 1973). (In Russian). Operation of the first operative linear induction accelerator showed that the method on which this accelerator is based makes it possible to obtain at efficiencies in tens of percent relativistic electron beams in hundreds and thousands of amperes reliably and repeatably. Intense development of accelerators of this type was carried out in a series of laboratories. Its theory and methods of calculation were developed. The results of works published in this area are systematized and discussed. The theory of linear induction accelerators, the form of the accelerating field, and the confinement of the high-current beam are examined. The parameters of both the operative and under-construction accelerators are reported and the construction of the basic subassemblies are briefly described. (tr-auth)

On the theory of stochastic acceleration of high energy particles in cyclic accelerators

The existing results on the theory of stochastic cyclic accelerators are extended using the methods of difference equations and random-walk theory. The theoretical guidelines provided by this paper should be sufficient to allow an evaluation of the feasibility of making a practical machine using the principle of stochastic acceleration.

Theory of Cyclic Accelerators

<i>Theory of Cyclic Accelerators</i>

Reactions of Accelerators during Vulcanization. II—A Theory of Accelerators Based on the Formation of Polysulfides during Vulcanization.

Reactions of Accelerators during Vulcanization. II—A Theory of Accelerators Based on the Formation of Polysulfides during Vulcanization.