Electron beam Definition and 63 Threads

Cathode rays (electron beam or e-beam) are streams of electrons observed in discharge tubes. If an evacuated glass tube is equipped with two electrodes and a voltage is applied, glass behind the positive electrode is observed to glow, due to electrons emitted from the cathode (the electrode connected to the negative terminal of the voltage supply). They were first observed in 1869 by German physicist Julius Plücker and Johann Wilhelm Hittorf, and were named in 1876 by Eugen Goldstein Kathodenstrahlen, or cathode rays. In 1897, British physicist J. J. Thomson showed that cathode rays were composed of a previously unknown negatively charged particle, which was later named the electron. Cathode-ray tubes (CRTs) use a focused beam of electrons deflected by electric or magnetic fields to render an image on a screen.

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  1. Philip Koeck

    A Can cooling enhance the monochromaticity of an electron beam?

    Does a beam of electrons become more monochromatic as it propagates? Can you cool an electron beam noticeably? I'm considering a very narrow beam of electrons with, for example an initial width in the order of 100 nm, and an energy around 1 keV and with a very small divergence angle (maybe 0.01...
  2. A

    E-beam evaporation, Physical vapour deposition

    Hi all, Hope we have some electron beam evaporation specialists in the house. I'm working with an Telemark Electron Beam Source (Linear Multi-pocket and would like some help with the issues I am facing currently. I'm seeing blue light around both sides of the crucible when the e-beam is turned...
  3. A

    I Does electron beam in empty space generate magnetic fields?

    Does electron beam in empty space generate magnetic fields around them just as with current in conductor. If yes, then is it experimentally proven that two parallel electron beam would attract each other.
  4. D

    Lessons with electron beam deflection tube and teltron tube

    Hello, I would like to discuss with my students the deflection of electrons in electric and magnetic fields. For this purpose, I would like to perform the experiments with electron beam deflection tubes and teltron tubes. How would you implement this organizationally in the classroom? There are...
  5. Christoffer B

    I Channel electron multiplier as an electron source

    Hi! I'm playing around with a type of electron (and by electron/molecule interactions: ion) source that was briefly touched upon in the 1960's. The basic idea is to use a channel electron multiplier "channeltron" with the anode removed; similar to a single MCP channel. The burst of electrons...
  6. Ilya B

    I Can a Black Hole be Destroyed by Electron Beam?

    Electrostatic repulsion of two electrons is about 4.17*10^42 stronger than their gravitational attraction, and is mediated by massless carriers. Black holes preserve charge, and charging a BH with even a moderate electric (negative) charge will result in BH repulsing electrons instead of...
  7. P

    Solving Part e of the Electron Beam Problem

    I am only asking about part e. If you are short on time, you can read through parts a - d, to get an idea of what is happening, and then attempt part e directly. I have solved parts a - d. If you would like to check your answers, the answer to part c is [rne^2 / 2e0] [ 1 - (v/c)^2], and the...
  8. H

    B Is an electron beam affected by photons?

    I am wondering if one of the prerequisites of the double-slit experiment, when done with electrons, is that the beams must be in a dark vacuum tube so as to not destroy the interference pattern. I am trying to learn if the beams will lose their interference pattern because the particles of the...
  9. A

    How Can the Optimum Aperture Angle in Electron Beam Lithography Be Determined?

    Hi, Is there anybody who knows about this subject and can guide kindly? Regards, In electron beam lithography, there is an optimum aperture angle to obtain a minimum beam size: a) Determine this angle considering only the influence of the source and spherical aberrations. b) What is the...
  10. B

    Deflection distance for an electron beam in an electric field

    Have tried doing this question but I'm a bit confused on where I'm going wrong This is what I have done but get a value that doesn't match to any of the options given above? Any help would be really appreciated, Thanks!
  11. E

    Radiation shielded Go-Pro camera sent through electron beam irradiator

    A radiation-shielded go-pro camera was sent through an electron beam irradiator. You can see the effects that the radiation has on the camera in the video. I wonder how many rads it was exposed to.
  12. F

    Proton Structure: De Broglie Wavelength & Resolution

    Hi all. I'd personally consider the De Broglie wavelength λ=h/p, with p being the momentum of the electron beam. I get $$\lambda \simeq 0.6 \times 10^{-18} m $$ and since the radius of a quark is ## \leq 10^{-19} m ##, the proton structure can't be resolved. I'm quite sure there's something...
  13. Zahid Iftikhar

    Collimation of an Electron Beam by the Anode of a CRT

    Please help me in understanding the function of anode. As in image attached you see, once the electron beam is emitted from cathode and filtered by grid, it enters into the one or series of anodes. As anode is positively charged, so, to my understanding it has no electric field inside its hollow...
  14. J

    B Electron Gun for a Grade 9 Physics Project?

    I am in grade 9 in the IB curriculum and next year I have to do something called a "Personal Project" where I have to make something and explain why I did it. I would like to recreate the double slit experiment. However, I have to obtain a electron gun and they are quite hard to come across. So...
  15. S

    Ejecting chemical species from a sample using an electron beam

    Hello, I was wondering if it would be possible to eject chemical compounds from a sample, say like a biological tissue, using an electron beam. I know that electron scattering is one product of electron-specimen interaction, and that's the principle behind electron microscopy, but I'm more...
  16. eigenmax

    Electron beam energy to acceleration potential relation

    Hi, How can I relate the beam energy of an electron beam produced by an electron gun to the accelerating potential? I realize that accelerating potential, initial energy (before acceleation), and losses by synchrotron radiation, etc, will play a part. I searched online and can't find much. Thanks
  17. SunRay-dvsh

    Oscillating Electron Beam potential between metal plates

    Take the case where the electron-beam is oscillating between two parallel metal plates, there will be alternating potential developed between the plates as metal tries to negate all external electric fields. My query is, (1) How to calculate the potential developed and possible way to simulate...
  18. moenste

    Calculate the speed of the electrons as they enter the gap

    Homework Statement Two parallel metal sheets of length 10 cm are separated by 20 mm in a vacuum. A narrow beam of electrons enters symmetrically between them as shown. When a PD of 1000 V is applied between the plates the electron beam just misses one of the plates as it emerges. Calculate...
  19. kiwaho

    A Anisotropic pinch force in high energy electron beam

    Here I am only considering 4 adjacent electrons in electron beam, especially the 2 electrons that are moving in tandem with velocity v. Moving charge will generate circular magnetic current. you can imagine magnetic flux as current, just like electric current. So, the question is same to find...
  20. kiwaho

    I Can electron beam accelerate electron capture beta decay?

    Some nuclides undergo decay of electron capture or beta plus. Can electron beam with appropriate energy accelerate electron capture beta decay? Same scenario: If I am looking for something, and my friend kindly hands it over to me, then I say thanks, because my seeking time is shorten.
  21. H

    Does an electron beam bending lose energy by photon emission

    A beam of electron in vacuum with velocity v enter a region of spa e with a electric field E. The field is such the electrons circle with radius r. The electrons are now accelerating at constant tangential speed. Because this is not an atomic orbital then by classical physics the electrons...
  22. Blackhawk4560

    Force on electron passing through Electric Field (calculate)

    Good afternoon, I hope this is in the right place... Anyway, diving right in- Say I have a classic CRT- How do I calculate the energy, in eV, that the electrons have upon reaching the anode? Also, is there a way to derive the speed of the electrons as well? See the attached image to...
  23. Blackhawk4560

    Calculating Vectors (in Joules) of an electromagnet

    Good afternoon, Question: Say I have an electromagnet at a 45 degree incline from an electron beam. This electromagnet is exerting 0.75 Tesla on the beam. How can I calculate the vector that the electromagnet will exert on a particle? Note, this is for my own curiosity, not for any homework...
  24. A

    Electron beam hitting a metal plate

    So i have this simple situation where i have an electron beam with a certain kinetic energy, and i have a metal plate connected to the ground, and the electrons hit the plate, now i want to know the voltage of the current in the wire to the ground. Now i know both kinetic energy of the electrons...
  25. A

    How Does Air Pressure Affect Electron Beam Penetration?

    Hey! I am trying to figure out this one problem. Some help would be appreciated. How can i relate the maximum distance traveled by an electron at a given pressure? So electron is colliding with air molecules. I wonder if there is a formula or derivation which relate maximum penetration and...
  26. Ornit

    Ion Assisted Deposition (coating technology)

    Hi all, When talking to some of our optics vendors, I got the impression that Ion Assisted Deposition (IAD) is standard. We use our optics at high power densities and we care about laser damage as well as adhesion and density of the coating (aka porosity, helps reduces sensitivity to humidity)...
  27. T

    Free electron beam inducing an EM field in a target?

    Consider the following experimental setup: the front half of a klystron tube (the electron gun and resonent cavity) or perhaps a free electron laser, several different targets consisting of a highly conductive(metal) object, a possibly conductive object(salt or clay), and a non-conductive...
  28. E

    What happens if you send a electron beam in a plasma?

    What happens when a electron travels through the plasma? Would it be likely that most of the electrons hit a nuclei or not? Would a beam of electrons work like a current through the plasma? Can you send electron beams with different voltage, and would it matter? In a hot plasma it's...
  29. A

    How Does Electron Beam Lithography Work for Patterning Gold on a Substrate?

    In an article I am reading gold wires a fabricated on top of a substrate using electron beam litography. How exactly does a procedure like this work? Electron beam litography uses a beam of electrons to pattern a substrate. What exactly does this pattern consist of and how can it be used to...
  30. E

    Investigating Return Current from Electron Beam in Plasma

    Hello everybody. I have a question about generation of return current in plasma beam interaction process: we enter an electron beam in a plasma medium, and this electron beam generate a return current in plasma, I want to know how electron current can produce a return current in plasma...
  31. E

    Generating Electron Beam: Tips & Explanations

    hello every body Can anyone help me for searching about this topic, How to generate electron beam? I want few information about electron source, in a simple explanation, and namely, not complete explanation . please help me. thanks.
  32. mesa

    In the Stern Gerlach experiment, electron beam acceleration question

    In the Stern Gerlach experiment it would seem that an electron beam moving at some velocity bisecting the upper magnet on a horizontal path would be radially accelerated perpendicular to the direction of motion. I am assuming from Lenz's Law this can be corrected by increasing the Bf...
  33. mesa

    Question about an electron beam traveling through static B-fields

    In the figures below is a sketch of an electron beam entering alternating static magnetic fields perpendicular to that of the motion of an electron beam. This beam is injected from a 45° angle below the x-axis. Figure 1 is a representation of this and is supposed to be an illustration of a basic...
  34. skate_nerd

    Deflection of electron beam in cathode ray tube

    Homework Statement Part a) Deflection of the electron beam in a cathode ray tube television set has electrons accelerated until they have K.E. of 25 keV. What is the magnetic field magnitude required to deflect the electron beam 3.3 cm when the magnetic field is 8 cm long? Part b) When...
  35. C

    Pion production with an electron beam

    If one directed a 3 GeV electron beam at a target (say carbon) would pions be produced? If so, what percentage would be produced compared to bombarding the same target with a 3 GeV proton beam? In other words, how important is it that electrons do not interact via the strong nuclear force...
  36. M

    Kinetic Energy of Electron Beam.

    Homework Statement Two horizontal plates connected to 600v with the positive at the top. A positively charged ion between the plates moves downwards under the force of the field (neglect gravity). The ion has charge 1.6×10^–19C and mass 2.3×10^–26kg. Show that the kinetic energy of the ion is...
  37. B

    Deflection of electron beam in oscilloscope

    Homework Statement Calculate the deflection of an electron beam as it passes between the plates of a CRT tube. In the picture, the parallel plates create an electric field, with the positive plate on top and the negative plate on bottom, causing the electron's path to be deflected upwards as...
  38. K

    Max distance of rectangle that electron beam can pass through

    Homework Statement A beam of electrons is fired into a rectangular region of space that contains a uniform magnetic field in the -z direction. The electrons are moving in the +x direction, as shown. The speed of the electrons in the beam is 6.00 × 106 m/s. The mass of an electron is me =...
  39. A

    Thickness of material to absorb electron beam

    Homework Statement Beam of electrons (charged particles!) is directed to copper absorber with known energy (E= 10MeV) and intensity (10^8(s*cm^2)^-1) . I need to find the thickness of absorber so that all electrons would be absorbed. Also under what conditions does it happen and what is...
  40. M

    Distance between electrons in electron beam?

    Homework Statement A beam of 9.5 MeV electrons (gamma = 20) amounting as a current to 0.05 microamperes, is traveling through a vacuum. The transverse dimensions of the beam are less than 1 mm, and there are no positive charges in or near it. (a) In the lab frame, what is approximately the...
  41. A

    How Can Two Electron Beams Be Manipulated to Merge and Exit on a Parallel Path?

    I have an engineering problem that I have to solve. Imagine that we have two electron beams, one originates from a heading of 0, coming toward point A. A line between the origin of beam 1 and point A would create a line of heading 0. Now a second beam, beam 2, originates from a heading of...
  42. V

    Estimation of reflected electron beam power falling on a target

    Hi, I need to calculate an estimate of the reflected electron beam power in the form of back scattered electrons and secondary electron emissions from a tungsten/Graphite target. The Electron source is a 25kV source with operated at a power of around 25kW. The tungsten. graphite blocks are...
  43. W

    Determine the dissociation energy with an electron beam

    Hi! If you use an electron beam on hydrogen gas and when the energy of the beam is 22 eV H+ start to appear, how can you calculate the dissociation energy of H2 using that information? I've tried: 22 eV = D + "ionization energy of a H atom" etc, but couldn't make it add up. I would be...
  44. atomqwerty

    Calculating Theta for Lowest Wavelength Electron Beam

    Homework Statement An electron beam (energy 119,9 eV) contacts perpendicularly on a Ni plate, with interatomic spacing d= 0,215 nm. At which angle Theta will be obtained an electron beam with the lower wavelenght possible? Homework Equations n\lambda=d sin(\theta) (Bragg's for...
  45. K

    Calculating temperature of electron beam

    I was curious. Does anyone know of anywhere were I might be able to find a formula for calculating the temperature of an electron beam? I already know the frequency and energy levels (actually calculating for multiple energies, so I have a spreadsheet I'd like to plug the equation into).
  46. R

    How Big Must V₀ Be for 40% Electron Beam Reflection?

    Electron beam with kinetic energy E_{k} = 10 eV strikes a positive potential barrier V_{0} and the kinetic energy after the beam has passed through the barrier is E_{k} = (10 eV -V_{0}). How big potential V_{0} is needed so that 40% of the electron beam is going to be reflected? What...
  47. S

    Magetic lens electron beam bremsstrahlung

    I am trying to find information about the creation of bremsstrahlung due to the convergence or deflection of an electron beam using an magnetic lens. I can not find any information about the creation of bremsstrahlung when electron beams pass through magnetic lenses, I have only found...
  48. M

    Understanding Current and its Properties: A Comprehensive Guide

    [b]1. The electron beam inside a television picture tube is 0.300 mm in diameter and carries a current of 52.0 mu A . This electron beam impinges on the inside of the picture tube screen. a)How many electrons strike the screen each second? b)What is the current density in the electron...
  49. P

    Electron Beam: Constant Distance Explored

    is the distance between electrons in an electron beam constant
  50. V

    Simulating electron beam - what equations to use?

    Hi, I'm doing a simulation of an electron beam. I've done integration of classical electrodynamics equations where I calculate electric fields with Coulomb force and magnetic fields with Lorentz force. I would like to know how to make this simulation more correct by using SR equations...
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