What is Linear accelerator: Definition and 28 Discussions

A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline. The principles for such machines were proposed by Gustav Ising in 1924, while the first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University.
Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy, serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles (electrons and positrons) for particle physics.
The design of a linac depends on the type of particle that is being accelerated: electrons, protons or ions. Linacs range in size from a cathode ray tube (which is a type of linac) to the 3.2-kilometre-long (2.0 mi) linac at the SLAC National Accelerator Laboratory in Menlo Park, California.

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  1. O

    I Linear Accelerator Length Contraction

    I am trying to understand the effect of relativistic length contraction on the electron bunches in a linear accelerator. Figure B is for nonrelativistic speeds, successive cylinder lengths are progressively longer. However, wikipedia says "At speeds near the speed of light, the incremental...
  2. R

    Size of bremsstrahlung radiation fields generated by linear accelerators

    Hi everyone, sorry we are talking about pulsed power accelerators again. In this context, it is about the HERMES III again. According to https://apps.dtic.mil/dtic/tr/fulltext/u2/a351472.pdf HERMES III, a 16 terawatt pulsed power accelerator at Sandia National Labs, which fired electron beams...
  3. R

    B Isodose contours of HERMES III

    These pictures below show four isodose contours of HERMES III with different anode-cathode gaps. The radiation produced are gamma rays. More informations can be seen here in the article https://www.osti.gov/biblio/6233581-hermes-iii-gamma-ray-facility-simulation-technology-laboratory-guide-users...
  4. R

    How far do gamma rays extend from an accelerator?

    According to https://www.osti.gov/servlets/purl/7234564, the HERMES III which stand for High Energy Radiation Megavolt Electron Source accelerator is "capable of delivering a peak dose of ~100 krad (CaF2) over a useful area of ~1000cm2 (area where dose is greater than 50% of the peak dose) in a...
  5. dsilvas

    Solving the Mystery: Exploring E << m Condition for Carbon 12 Ions

    Clarification: The statement in the title is actually from the solution to the homework question, as given by the textbook (you can see the whole thing below under "Textbook solution"). The solution doesn't explain everything, which is where my confusion comes from. Usually in my classes we...
  6. f77hacker

    A Rayleigh length to electron bunch emittance

    Hello, Context is Inverse Compton Scattering with an pulsed electron beam interacting with a pulsed laser. A laser has a Raleigh length of Z_r = w_o^2 * pi / lambda w_o is the the radius of the spot size, lambda is the laser frequency. I want to match this spot size to a pulsed electron bunch...
  7. W

    Building a linear accelerator -- radiation shielding, O2-,

    So, I have no education in this field. I've really been into mutant breeding and crisper plasmid based genetic engineering. I've read that heavy ions create a greater number of mutagens than electron magnetic radiation such as deep uvc. lately particle accelerators have been on my mind. I'm...
  8. D

    Gauss' gun/magnetic linear accelerator

    Hi, I'm currently doing my extended essay for the IB in physics and I'm basing mine around the Gauss gun (similar post that explains it really well here https://www.physicsforums.com/threads/physics-behind-gaussian-accelerator-magnetic-linear-accelerator.320389/). What I was wondering was how I...
  9. AndresPB

    I Acceleration of a Particle Because of a Wave

    Hello all, I would like to know why an electron is accelerated in a linear accelerator because of the microwaves emitted by a magnetron?. Can someone tell me what are the relevant physics equations and what is the role of skin-effect here? Thanks a lot.
  10. J

    I Video that show how a linear accelerator was built in 1967

    Hi folks, I have just found a video on youtube that shows how a 2 mile linear accelerator was built in 1967, I share it with you, hopefully you will enjoy it as much as I did:
  11. I

    I Is this Linear Accelerator Design Valid?

    Good Evening Everyone, A group of friends and I were having a mini-contest, to see who could theoretically make anti-matter using the most simplistic design in terms of cost and general complexity. The obvious choice for us was the Positron, due to low energy requirements on all fronts. One of...
  12. M

    Particle in linear accelerator

    Homework Statement An electron (e=1.6x10^(-19) Coulomb) of total energy 10.22 MeV (\gamma about 20) is undergoing linear acceleration due to application of a uniform electric field of strenght E_0=1000 MV/m a)how large is the applied force, in Newton? b) Calculate the instantaneous radiated...
  13. Z

    Finding the Velocity of a BB on a Magnetic Linear Accelerator

    As is in the title, I am looking for a better way to measure the velocity of a ball bearing (actually only looking for speed) that has been accelerated by a magnetic. If you don't know what a Magnetic Linear Accelerator is, then this link/video should help: I already have some success...
  14. M

    Converting Linear Accelerator To Circular One

    Hi guys , Suppose there is a circular accelerator has the same inner structure of a linear accelerator in terms of the rings of acceleration ... The angular frequency of accelerated particles is : ω = qB/m = 2πf , and this is also the supplied current frequency ... The question is ...
  15. J

    A question about linear accelerator and relativistic momentum

    A 3.2km linear accelerator(linac) accelerates electrons constantly down the linac,each electron will have 50GeV of energy at the exit point. what is the speed of the electron after going 1m down the accelerator? After electrons exit the linac,magnets are used to curve the electron beams. the...
  16. L

    Why does the output of a linear accelerator increase in time?

    I was reading that i certain type of linear accelerator increases in output though time... why would this be? If anything i would have thought it would have been the opposite.. thanks
  17. J

    Linear Accelerator Basics: Understanding Drift Tubes and Forces

    Homework Statement Could someone please fill in the gaps in my knowledge about Linear Accelerators. The drift tubes are spaced equally apart. BUT the electrons speed up in between the tubes so surely the distance between the tubes should increase as does the length of the drift tubes...
  18. N

    Question about simple linear accelerator

    Hello, Lets say we have linear accelerator with uniform electric field E and length L. Lets an electron enters it with high speed v0. How to calculate speed v the electron will have in output? Thank you.
  19. S

    How does a linear accelerator produce X-rays?

    Hi all, I am new to the forums, so try to persevere with my general lack of knowledge. I am a student at high school and we have just recently been studying a unit in nuclear and atomic physics. I understand all the basic concepts such as the photoelectric effect, Planck's constant, electron...
  20. S

    How to power an RF Linear Accelerator?

    I want to build a small linear accelerator with an energy level around 2-2.5 MeV and as much beam current as I can get without getting too exotic (but I'll be happy with whatever I can get initially). I will need a means of generating microwave RF with the power requirements, I'm guessing, to...
  21. Y

    Magnetic Linear Accelerator Questions

    Firstly, I am sorry if I sound like a moron I only finished 1 year at university before leaving so I don't have the firmest grasp on some of this. I do have a massive facination with nuclear physics and quantum mechanics, string theory etc. Secondly, Im looking at building a linear accelerator...
  22. X

    Physics behind Gaussian Accelerator/ Magnetic Linear Accelerator

    Hi all. i have seen some videos on youtube and i am amazed by the videos of Gaussian accelerator/ Magnetic linear accelerator. As i have a physics project coming up i may consider using this for my project, however i need to ensure that this experiment is within my syllabus. i have basically...
  23. T

    Building a Linear Accelerator at Home: Safety Concerns

    I am making a proof-of-concept linear accelerator with one stage at home ( if i can call it such ).The vacuum chamber is a 40cm transparent pipe with a radius of 10mm.The particles are accelerated by an electrical field created at the two ends of the tube with a voltage of 20kV.I need an...
  24. E

    Magnetic Linear Accelerator ( finding magnets)

    So i have decided for my physics project to build a magnetic linear accelerator made with half inch ball bearings on a plastic track. The first bearing is rolled and accelerated by the magnet which when struck, launches the ball on the other side due to the momentum of the accelerated bearing...
  25. M

    Magnetic linear Accelerator + Newton's Balls

    It is time for my HS Physics Class final project. I have about a month to design and build a piece of equipment to show my knowledge of any topic we have covered this year. My idea was to have a basic small magnetic linear accelerator ( just basic type for shooting steel balls such as this...
  26. C

    Linear accelerator physics problem

    Ive been working on this problem for a few hours and can't get the last few parts. In a linear accelerator, protons are accelerated from rest through a potential difference to a speed of approximately 3.1 X 10^6 meters per second. The resulting proton beam produces a current of 2 X 10^-6...
  27. D

    Linear Accelerator (Gauss Rilfe)

    This is a little bit of a mouthful but any help would be greatly appreciated. :smile: I am building a linear accelerator similar to the one found on this site: http://www.scitoys.com/scitoys/scitoys/magnets/gauss.html This is for a physics 12 project with my friends, but only it is on a...
  28. R

    How Does a Linear Accelerator Work and What's the Cost of a DIY Laser?

    does somebody knows how a linear acccelerator works or know any website about the accelerators. and how much it costs to built a cheap home made laser.