Open Access. Powered by Scholars. Published by Universities.®

Physics Commons™

Open Access. Powered by Scholars. Published by Universities.®

PDF

Electron

Discipline
Institution
Publication Year
Publication
Publication Type

Articles 1 - 30 of 115

Full-Text Articles in Physics

Beyond Standard Model: Neutrino Dipoles And Proto Hydrogen Bundles., Polievkt Perov Mar 2024

Beyond Standard Model: Neutrino Dipoles And Proto Hydrogen Bundles., Polievkt Perov

College of Arts & Sciences Faculty Works

In our composite models of elementary particles as consisting of just two types of elementary basic charges, +e/3 and -e/3, the axial electric potential of any elementary particle is a function of a distance from the particle, and this function differs from the Coulomb potential of a point total charge of the particle. The electric potential of neutrinos is not zero at close distances from neutrinos. Neutrinos can form dipoles and bundles of 3 or more neutrinos. The three-neutrino bundle (a proto-hydrogen) can be converted to a hydrogen atom. As we suggested in our previous paper [4], the total numbers …

Go to article

Beyond Standard Model: Electrostatic Potential Energy Of Quarks, Electron, And Neutrinos As Spinning Composite Structures, Polievkt Perov Mar 2024

Beyond Standard Model: Electrostatic Potential Energy Of Quarks, Electron, And Neutrinos As Spinning Composite Structures, Polievkt Perov

College of Arts & Sciences Faculty Works

The potential energy of any composite structure is related to the binding energy of the structure. The equations for the electrostatic potential energy of quarks, electron-like structures, and neutrinos are presented for our models of elementary particles as spinning composite structures. The structures consist of up to 3 basic elementary charges of magnitude e/3 on the axis of rotation and N charges revolving about the axis. We applied these general equations specifically to the models of different quarks, electron and electron-like particles (muon and tau), and neutral particles (neutrinos). It is shown that the electrostatic potential energies of all considered …

Go to article

Beyond Standard Model: Axial Electric Potentials Of Quarks And Neutrinos, Polievkt Perov Feb 2024

Beyond Standard Model: Axial Electric Potentials Of Quarks And Neutrinos, Polievkt Perov

College of Arts & Sciences Faculty Works

The equations of axial electric potentials are presented for our models of quarks and neutrinos as spinning composite structures where up to 3 basic elementary charges are on the axis or rotation and the other N charges are revolving about the axis. The axial potential functions at given point on the axis of rotation were calculated as the sum of electric potentials at that point from all the charges in the structure. We applied these general equations specifically to the models of two types of neutral particles (neutrinos), one with 2 like charges on the axis and the other with …

Go to article

Beyond Standard Model: Structure Factors Of Models Of Different Quarks And Neutrinos As Spinning Structures Made Of Basic Fractional Charges +- E/3, Polievkt Perov Jan 2024

Beyond Standard Model: Structure Factors Of Models Of Different Quarks And Neutrinos As Spinning Structures Made Of Basic Fractional Charges +- E/3, Polievkt Perov

College of Arts & Sciences Faculty Works

We consider a possible line of “elementary” particles as composite spinning structures made of just two basic elementary particles of charges + e/3 and -e/3. In considered structures, up to 3 basic charges can be on the axis of rotation and other charges can be in a revolving motion about the axis. In addition to the simplest structures of quarks, an electron and a neutral particle containing mostly one or no charges on the axis of rotation, suggested initially in [4], we analyze possible spatial structures of spinning composite particles having 2 or 3 charges on the axis of rotation. …

Go to article

Electron As A Structure Made Of Basic Elementary Particles: Spinning Speed And Radius, Polievkt Perov Sep 2023

Electron As A Structure Made Of Basic Elementary Particles: Spinning Speed And Radius, Polievkt Perov

College of Arts & Sciences Faculty Works

We have calculated the orbital speed, the radius of an orbit of the revolving basic particles, and the angular speed of an electron in three models of an electron as a spinning composite particle. The three models suggested in our previous work [1] are the centered square structure, the rhombus structure, and the tetrahedral structure. The calculated speed of revolving basic particles, for all three models of an electron, does not exceed c, the maximum possible speed in nature: for the centered square model, in the rhombus model, and in the tetrahedral model. The results show that the spin of …

Go to article

Precise Determination Of Charge Distributions In Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements With Applications To Spacecraft Charging, Zachary Gibson Aug 2023

Precise Determination Of Charge Distributions In Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements With Applications To Spacecraft Charging, Zachary Gibson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding how charge builds up and moves around in materials that are highly insulating, such as dielectrics, is important for many applications from power transmission to spacecraft charging. The leading cause of issues in spacecraft due to interactions with the space environment is spacecraft charging. That is, the accumulation of charge on insulating materials leads to arcing and sparking aboard the spacecraft. The most critical charging occurs due to electrons in a particular energy range of 10-50 keV. Electrons with these energies can travel 1’s to 10’s of microns into relevant materials. To measure where the charge is embedded and …

Go to article

Fractional Charge Concept Opened Gates For New Ideas On Composition Of Matter, Polievkt Perov Jun 2023

Fractional Charge Concept Opened Gates For New Ideas On Composition Of Matter, Polievkt Perov

College of Arts & Sciences Faculty Works

Before the concept of quarks with fractional electric charges was introduced, the electron charge magnitude e was considered as the smallest amount of charge in nature so the charge of any object could be only an integer number of ± e. Then it was suggested that the proton and neutrons are composed of quarks with the fractional charges, combined in such a way that the total charge of a proton occurred to be that same known charge +e, and the charge of a neutron was zero. We suggest expanding that fruitful concept of fractional charges to build structural models of …

Go to article

New Reaction Of Neutron-Proton Conversion, Polievkt Perov Jun 2023

New Reaction Of Neutron-Proton Conversion, Polievkt Perov

College of Arts & Sciences Faculty Works

Using our models of composite particles as consisting just of two types of elementary basic charges, +e/3 and -e/3, we suggest that in any nuclear reaction the total numbers of basic charges of each of the two types are conserved. That means that in any nuclear reaction, the basic elementary charges present in the reactants can join in different combinations to form the products of the reaction. This is like a balanced chemical equation where the number of atoms of each element is conserved. We apply this suggested principle of conservation of basic elementary charges in any nuclear reaction to …

Go to article

Electron-Hole Trapping Centers In Alkali Metal Sulfates With Dy3+ Impurities, T.N. Nurakhmetov, T.T. Alibay, R.Z. Bakhtizin, S. Pazylbek, A.Zh. Kainarbay, A.M. Zhunusbekov, B.M. Sadykova, D.A. Tolekov, R.K. Shamieva, A.S. Nurpeissov Jun 2023

Electron-Hole Trapping Centers In Alkali Metal Sulfates With Dy3+ Impurities, T.N. Nurakhmetov, T.T. Alibay, R.Z. Bakhtizin, S. Pazylbek, A.Zh. Kainarbay, A.M. Zhunusbekov, B.M. Sadykova, D.A. Tolekov, R.K. Shamieva, A.S. Nurpeissov

Eurasian Journal of Physics and Functional Materials

The Na2SO4 − Dy samples were obtained by slow evaporation method. The spectroscopic methods were used to study the mechanisms of formation of electron and hole trapping centers. Intrinsic recombination emission of 2.9–3.1 eV and impurity emission of 2.55 eV and 2.15 eV are excited at 4.0–4.5 eV. Intrinsic SO3−4− SO−4 and impurity Dy2+−SO−4 trapping centers were revealed. The local levels corresponding between the electron and hole trapping center are 4.0–4.5 eV.

Go to article

Electron And Other Quarks As Particles Made Of Elementary Particles Of Charge E/3 And Mass Me/6, Polievkt Perov May 2023

Electron And Other Quarks As Particles Made Of Elementary Particles Of Charge E/3 And Mass Me/6, Polievkt Perov

College of Arts & Sciences Faculty Works

We suggest that the first-generation quarks are not elementary particles, but structures made of a basic elementary particle of charge e/3 and its antiparticle, interacting via an electrostatic force. The structures are suggested for d-quark as consisting of one positive and two negative basic elementary charges, for u-quark as a structure with one negative and three positive basic charges, for an electron as a quark with one positive and four negative basic charges, and for one more quark made of one positive and one negative basic charge. All the suggested structures are in a spinning motion and are stable. The …

Go to article

Electron-Hole Trapping Centers In Na2so4 With A Transition Metal Impurity Mn, T.N. Nurakhmetov, T.T. Alibay, S. Pazylbek, A.M. Zhunusbekov, B.M. Sadykova, D.A. Tolekov, R.K. Shamieva, A.S. Nurpeissov Mar 2023

Electron-Hole Trapping Centers In Na2so4 With A Transition Metal Impurity Mn, T.N. Nurakhmetov, T.T. Alibay, S. Pazylbek, A.M. Zhunusbekov, B.M. Sadykova, D.A. Tolekov, R.K. Shamieva, A.S. Nurpeissov

Eurasian Journal of Physics and Functional Materials

The Na2SO4 samples were obtained by slow evaporation method. The mechanisms of the formation of electron and hole trapping centers are investigated by spectroscopic methods. Intrinsic recombination emission of 2.9–3.1 eV and impurity emission of 1.85 eV are excited at 4.0–4.5 eV. Intrinsic SO3−4−SO−4 and impurity Mn+ − SO−4 trapping centers were revealed. The local levels corresponding between the electron and hole trapping center are 4.0–4.5 eV. The decay of intrinsic and impurity trapping centers was recorded at temperatures of 130–150 K and 280–350 K.

Go to article

A Study Of Electron Plasma Oscillations Using The Nimrod Code, Mckay Murphy Dec 2022

A Study Of Electron Plasma Oscillations Using The Nimrod Code, Mckay Murphy

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

A plasma, whether ”hot” or ”cold,” magnetized or unmagnetized, electrostatic or electromagnetic, exhibits normal modes of oscillation. Critical to understanding the stability of a plasma is the study of these normal modes. Waves originate from the long-range electric interactions between charged particles. This work will consider a class of waves known as Langmuir waves. These waves occur when a group of electrons are displaced with respect to the ions, with the electric Coulomb force playing the role of the restoring force of the oscillation [1]. Since the mass of ions is much greater than that of electrons, we can approximate …

Go to article

Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang Jan 2022

Cooling Performance In A Dual Energy Storage Ring Cooler, B. Dhital, Y. S. Derbenev, D. Douglas, G. A. Krafft, H. Zhang, F. Lin, V. S. Morozov, Y. Zhang

Physics Faculty Publications

The longitudinal and transverse emittance growth in hadron beams due to intra-beam scattering (IBS) and other heating sources deteriorate the luminosity in a collider. Hence, a strong hadron beam cooling is required to reduce and preserve the emittance. The cooling of high energy hadron beam is challenging. We propose a dual energy storage ring-based electron cooler that uses an electron beam to extract heat away from hadron beam in the cooler ring while the electron beam is cooled by synchrotron radiation damping in the high energy damping ring. In this paper, we present a design of a dual energy storage …

Go to article

Modeling A Nb3Sn Cryounit In Gpt In Uitf, Sunil Pokharel, Geoffey A. Krafft, A. S. Hofler Jan 2022

Modeling A Nb3Sn Cryounit In Gpt In Uitf, Sunil Pokharel, Geoffey A. Krafft, A. S. Hofler

Physics Faculty Publications

Nb₃Sn is a prospective material for future superconducting RF (SRF) accelerator cavities. The material can achieve higher quality factors, higher temperature operation and potentially higher accelerating gradients (E_{acc} 96 MV/m) compared to conventional niobium. In this work, we performed modeling of the Upgraded Injector Test Facility (UITF) at Jefferson Lab utilizing newly constructed Nb₃Sn cavities. We studied the effects of the buncher cavity and varied the gun voltages from 200-500 keV. We have calibrated and optimized the SRF cavity gradients and phases for the Nb₃Sn five-cell cavities energy gains with the framework of General Particle Tracer (GPT). Our calculations show …

Go to article

Lower Temperature Annealing Of Vapor Diffused Nb3Sn For Accelerator Cavities, Jayendrika K. Tiskumara, Jean R. Delayen, G. V. Eremeev, U. Pudasaini Jan 2022

Lower Temperature Annealing Of Vapor Diffused Nb3Sn For Accelerator Cavities, Jayendrika K. Tiskumara, Jean R. Delayen, G. V. Eremeev, U. Pudasaini

Physics Faculty Publications

Nb3Sn is a next-generation superconducting material for the accelerator cavities with higher critical temperature and superheating field, both twice compared to Nb. It promises superior performance and higher operating temperature than Nb, resulting in significant cost reduction. So far, the Sn vapor diffusion method is the most preferred and successful technique to coat niobium cavities with Nb3Sn. Although several post-coating techniques (chemical, electrochemical, mechanical) have been explored to improve the surface quality of the coated surface, an effective process has yet to be found. Since there are only a few studies on the post-coating heat treatment …

Go to article

Improved Electrostatic Design Of The Jefferson Lab 300 Kv Dc Photogun And The Minimization Of Beam Deflection, M. A. Mamun, D. B. Bullard, J. R. Delayen, J. M. Grames, C. Hernandez-Garcia, Geoffrey A. Krafft, M. Poelker, R. Suleiman, S.A.K. Wijethunga Jan 2022

Improved Electrostatic Design Of The Jefferson Lab 300 Kv Dc Photogun And The Minimization Of Beam Deflection, M. A. Mamun, D. B. Bullard, J. R. Delayen, J. M. Grames, C. Hernandez-Garcia, Geoffrey A. Krafft, M. Poelker, R. Suleiman, S.A.K. Wijethunga

Physics Faculty Publications

An electron beam with high bunch charge and high repetition rate is required for electron cooling of the ion beam to achieve the high luminosity required for the proposed electron-ion colliders. An improved design of the 300 kV DC high voltage photogun at Jefferson Lab was incorporated toward overcoming the beam loss and space charge current limitation experienced in the original design. To reach the bunch charge goal of ~ few nC within 75 ps bunches, the existing DC high voltage photogun electrodes and anode-cathode gap were modified to increase the longitudinal electric field (Ez) at the photocathode. The anode-cathode …

Go to article

Bunch Length Measurements At The Cebaf Injector At 130 Kv, Sunil Pokharel, M. W. Bruker, J. M. Grames, A. S. Hofler, R. Kazimi, Geoffrey A. Krafft, S. Zhang Jan 2022

Bunch Length Measurements At The Cebaf Injector At 130 Kv, Sunil Pokharel, M. W. Bruker, J. M. Grames, A. S. Hofler, R. Kazimi, Geoffrey A. Krafft, S. Zhang

Physics Faculty Publications

In this work, we investigated the evolution in bunch length of beams through the CEBAF injector for low to high charge per bunch. Using the General Particle Tracer (GPT), we have simulated the beams through the beamline of the CEBAF injector and analyzed the beam to get the bunch lengths at the location of chopper. We performed these simulations with the existing injector using a 130 kV gun voltage. Finally, we describe measurements to validate these simulations. The measurements have been done using chopper scanning technique for two injector laser drive frequency modes: one with 500 MHz, and another with …

Go to article

New Results At Jlab Describing Operating Lifetime Of Gaas Photo-Guns, M. Bruker, J. Grames, C. Hernández-García, M. Poelker, S. Zhang, V. Lizárraga-Rubio, C. Valerio-Lizárraga, Joshua T. Yoskowitz Jan 2022

New Results At Jlab Describing Operating Lifetime Of Gaas Photo-Guns, M. Bruker, J. Grames, C. Hernández-García, M. Poelker, S. Zhang, V. Lizárraga-Rubio, C. Valerio-Lizárraga, Joshua T. Yoskowitz

Physics Faculty Publications

Polarized electrons from GaAs photocathodes have been key to some of the highest-impact results of the Jefferson Lab science program over the past 30 years. During this time, various studies have given insight into improving the operational lifetime of these photocathodes in DC high-voltage photo-guns while using lasers with spatial Gaussian profiles of typically 0.5 mm to 1 mm FWHM, cathode voltages of 100 kV to 130 kV, and a wide range of beam currents up to multiple mA. In this contribution, we show recent experimental data from a 100 kV to 180 kV setup and describe our progress at …

Go to article

197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao Jan 2022

197 Mhz Waveguide Loaded Crabbing Cavity Design For The Electron-Ion Collider, Subashini De Silva, Jean Delayen, J. Guo, R. A. Rimmer, Z. Li, B. P. Xiao

Physics Faculty Publications

The Elec­tron-Ion Col­lider will re­quire crab­bing sys­tems at both hadron and elec­tron stor­age rings in order to reach the de­sired lu­mi­nos­ity goal. The 197 MHz crab cav­ity sys­tem is one of the crit­i­cal rf sys­tems of the collider. The crab cav­ity, based on the rf-di­pole de­sign, explores the op­tion of wave­guide load damp­ing to sup­press the higher order modes and meet the tight im­ped­ance spec­i­fi­ca­tions. The cav­ity is de­signed with com­pact dog-bone wave­guides with tran­si­tions to rec­tan­gu­lar wave-guides and wave­guide loads. This paper pre­sents the com­pact 197 MHz crab cav­ity de­sign with wave­guide damp­ing and other an­cil­lar­ies.

Go to article

Triply Differential Positron And Electron Impact Ionization Of Argon: Systematic Features And Scaling, Robert D. Dubois, O. G. De Lucio Dec 2021

Triply Differential Positron And Electron Impact Ionization Of Argon: Systematic Features And Scaling, Robert D. Dubois, O. G. De Lucio

Physics Faculty Research & Creative Works

Triply differential data are presented for the 200 eV positron and electron impact ionization of argon. Six electron emission energies between 2.6 and 19 eV, and for scattering angles of 2, 3, and 4 degrees cover a momentum transfer range of 0.16 to 0.31 a.u. The binary and recoil intensities are fitted using a double peak structure in both regions, which, for the present kinematic conditions, are unresolved. The fitted peak intensities and angular positions are shown to have systematic dependences as a function of the momentum transfer and kinematic emission angle, respectively, and illustrate projectile charge effects. A comparison …

Go to article

Mechanisms For The Creation Of Intrinsic Electron-Hole Trapping Centers In A Caso4 Crystal, T. N. Nurakhmetov, K. B. Zhangylyssov, A. M. Zhunusbekov, D. H. Daurenbekov, T. T. Alibay, B. M. Sadykova, B. N. Yussupbekova, D. A. Tolekov Sep 2021

Mechanisms For The Creation Of Intrinsic Electron-Hole Trapping Centers In A Caso4 Crystal, T. N. Nurakhmetov, K. B. Zhangylyssov, A. M. Zhunusbekov, D. H. Daurenbekov, T. T. Alibay, B. M. Sadykova, B. N. Yussupbekova, D. A. Tolekov

Eurasian Journal of Physics and Functional Materials

The mechanism of creation of electron-hole trapping centers in CaSO4 at 15-300 K was investigated by the methods of vacuum-ultraviolet and thermoactivation spectroscopy. It is shown that electron-hole trapping centers are formed upon trap of electrons in the anionic complexes SO2. and localization 4 of holes in the form of SO. radical. Based on the measurement of the spectrum of excitation of 4 long-wavelength recombination emission at 3.0-3.1 eV and 2.7 eV, the energy distance of the formed electron-hole trapping centers was estimated (4.43 eV and 3.87 eV).

Go to article

Intrinsic Emission And Electron-Hole Trapping Centers In Li2so4-Cu Crystals, T. N. Nurakhmetov, Zh. M. Salikhodzha, M. Y. Dolomatov, B. N. Yussupbekova, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, B. M. Sadykova, K. B. Zhangylyssov, T. T. Alibay, D. A. Tolekov Jun 2021

Intrinsic Emission And Electron-Hole Trapping Centers In Li2so4-Cu Crystals, T. N. Nurakhmetov, Zh. M. Salikhodzha, M. Y. Dolomatov, B. N. Yussupbekova, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, B. M. Sadykova, K. B. Zhangylyssov, T. T. Alibay, D. A. Tolekov

Eurasian Journal of Physics and Functional Materials

In thepresent work, the emission and excitation spectrain Li2SO4-Cu crystalshave been obtainedby the methods of vacuum-ultraviolet and thermoactivation spectroscopy. We have studied the nature of emission from a pressed and annealed sample of Li2SO4-Cu powders. It has been revealed that at low temperatures Cu0-SO. -centers are formed during the trap of electrons by Cu+ -centers and during 4 localization of SO. 4 -radicals in the form of localized hole centers.

Go to article

Mechanisms Of Formation Of Electron Hole Trap Centers In Likso4 Crystal, T. N. Nurakhmetov, Zh. M. Salikhodzha, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, T. T. Alibay, B. M. Sadykova, K. B. Zhangylyssov, B. N. Yussupbekova, D. A. Tolekov Mar 2021

Mechanisms Of Formation Of Electron Hole Trap Centers In Likso4 Crystal, T. N. Nurakhmetov, Zh. M. Salikhodzha, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, T. T. Alibay, B. M. Sadykova, K. B. Zhangylyssov, B. N. Yussupbekova, D. A. Tolekov

Eurasian Journal of Physics and Functional Materials

The mechanisms of creation of electron-hole trapping centers in LiKSO4 have been investigated by the methods of vacuum and thermal activation spectroscopy. It is shown that electron-hole trapping centers are formed during the trappingof electronsbyanionic complexes and localizationofa holein the lattice in the form of the radical SO. . The appearance of phosphorescence at 3.0-3.1 eV, 2.6-2.7 eV and 2.3-2.4 4 eV confirms the creation of electron-hole trap centers.

Go to article

Energy Transfer Of Intrinsic Electronic Excitation To Impurities In The Caso4-Mn System, T. N. Nurakhmetov, Zh. M. Salikhodzha, K. B. Zhangylyssov, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, Zh. Azmagambetova, B. M. Sadykova, B. N. Yussupbekova, T. T. Alibay, D. A. Tolekov, N. Tulebayeva Mar 2021

Energy Transfer Of Intrinsic Electronic Excitation To Impurities In The Caso4-Mn System, T. N. Nurakhmetov, Zh. M. Salikhodzha, K. B. Zhangylyssov, A. M. Zhunusbekov, A. Zh. Kainarbay, D. H. Daurenbekov, Zh. Azmagambetova, B. M. Sadykova, B. N. Yussupbekova, T. T. Alibay, D. A. Tolekov, N. Tulebayeva

Eurasian Journal of Physics and Functional Materials

The nature of the impurity emission center and the energy transfer mechanisms from intrinsic electronic excitations to the Mn2+ impurity centers in the CaSO4 . Mn crystal have been investigated. The methods of vacuum ultraviolet, atomic absorption and luminescence spectroscopy are used in a wide temperature range from 5 K to 300 K. The energy transfer of intrinsic electronic excitations to impurity emission centers in CaSO4 . Mn has been detected.

Go to article

Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner Mar 2021

Study Of Neon Collisional Negative Ion Compound Resonance Using A Trochoidal Electron Monochromator, Will Brunner

Honors Theses

This thesis describes the experimental apparatus and procedure used to measure the excitation function of the 2p53p 3D3 state of neon. First I describe the effect on this excitation of negative ion resonances and previous experiments to measure the excitation function, as well as suggestions for future applications of such studies. Then the experimental apparatus is described in three parts. The vacuum system uses a turbomolecular pump to decrease the pressure of the chamber to as low as 4*10-9 Torr. The electron beam system incorporates a trochoidal electron monochromator to send a highly monochromatic beam …

Go to article

Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer Mar 2021

Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer

Honors Theses

When an electron beam travels through space, it spreads out over time which impedes the ability to work with short electron pulses in the lab. A Wien filter is a device consisting of perpendicular electric and magnetic fields which filters charged particles based on their velocities. For a specific velocity, the two forces from the two fields in the filter cancel each other out letting charges with that velocity travel straight through the filter. Charges moving at other speeds are deflected as they have a net force applied to them from the filter. If a particle is deflected from the …

Go to article

Design Of An Rf-Dipole Crabbing Cavity System For The Electron-Ion Collider, Subashini U. De Silva, Jean R. Delayen, H. Park, F. Marhauser, J. Henry, R. A. Rimmer Jan 2021

Design Of An Rf-Dipole Crabbing Cavity System For The Electron-Ion Collider, Subashini U. De Silva, Jean R. Delayen, H. Park, F. Marhauser, J. Henry, R. A. Rimmer

Physics Faculty Publications

The Electron-Ion Collider requires several crabbing systems to facilitate head-on collisions between electron and proton beams in increasing the luminosity at the interaction point. One of the critical rf systems is the 197 MHz crabbing system that will be used in crabbing the proton beam. Many factors such as the low operating frequency, large transverse voltage requirement, tight longitudinal and transverse impedance thresholds, and limited beam line space makes the crabbing cavity design challenging. The rf-dipole cavity design is considered as one of the crabbing cavity options for the 197 MHz crabbing system. The cavity is designed including the HOM …

Go to article

Redesign Of The Jefferson Lab -300 Kv Dc Photo-Gun For High Bunch Charge Operations, S.A.K. Wijethunga, J. Benesch, Jean R. Delayen, C. Hernandez-Garcia, Geoffrey A. Krafft, Gabriel Palacios-Serrano, M.A. Mamun, M. Poelker, R. Suleiman Jan 2021

Redesign Of The Jefferson Lab -300 Kv Dc Photo-Gun For High Bunch Charge Operations, S.A.K. Wijethunga, J. Benesch, Jean R. Delayen, C. Hernandez-Garcia, Geoffrey A. Krafft, Gabriel Palacios-Serrano, M.A. Mamun, M. Poelker, R. Suleiman

Physics Faculty Publications

Production of high bunch charge beams for the ElectronIon Collider (EIC) is a challenging task. High bunch charge (a few nC) electron beam studies at Jefferson Lab using an inverted insulator DC high voltage photo-gun showed evidence of space charge limitations starting at 0.3 nC, limiting the maximum delivered bunch charge to 0.7 nC for beam at -225 kV, 75 ps (FWHM) pulse width, and 1.64 mm (rms) laser spot size. The low extracted charge is due to the modest longitudinal electric field (Ez) at the photocathode leading to beam loss at the anode and downstream beam pipe. To reach …

Go to article

Few Body Effects In The Electron And Positron Impact Ionization Of Atoms, R. I. Campeanu, Colm T. Whelan Jan 2021

Few Body Effects In The Electron And Positron Impact Ionization Of Atoms, R. I. Campeanu, Colm T. Whelan

Physics Faculty Publications

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will …

Go to article

Beam Dynamics Study In A Dual Energy Storage Ring For Ion Beam Cooling*, B. Dhital, Y. S. Derbenev, D. Douglas, A. Hutton, Geoffrey A. Krafft, F. Lin, V. S. Morozov, Y. Zhang Jan 2021

Beam Dynamics Study In A Dual Energy Storage Ring For Ion Beam Cooling*, B. Dhital, Y. S. Derbenev, D. Douglas, A. Hutton, Geoffrey A. Krafft, F. Lin, V. S. Morozov, Y. Zhang

Physics Faculty Publications

A dual energy storage ring designed for beam cooling consists of two closed rings with significantly different energies: the cooling and damping rings. These two rings are connected by an energy recovering superconducting RF structure that provides the necessary energy difference. In our design, the RF acceleration has a main linac and harmonic cavities both running at crest that at first accelerates the beam from low energy E_{L} to high energy E_{H} and then decelerates the beam from E_{H} to E_{L} in the next pass. The purpose of the harmonic cavities is to extend the bunch length in a dual …

Go to article

Next Last