1 / 13

High voltage

High voltage. DC Beam steering Beam focusing Reaction product guiding (e - ) High voltage barriers AC Acceleration Bunching. Electric rigidity. Bend the particle beam with an electric field. Bending voltage. E.g. V acc =130 MV d = 5 mm r = 1 m V bend = 1.3 MV !!!!!!!!!!!

maxwell-allen
Download Presentation

High voltage

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. High voltage • DC • Beam steering • Beam focusing • Reaction product guiding (e-) • High voltage barriers • AC • Acceleration • Bunching

  2. Electric rigidity Bend the particle beam with an electric field

  3. Bending voltage • E.g. • Vacc=130 MV • d = 5 mm • r = 1 m • Vbend = 1.3 MV !!!!!!!!!!! • Bending very difficult!!! • Very high voltages

  4. High voltage devices Einzel lens Electrostatic deflector

  5. Power supplies • P (+) • N (-) • R (+ or -)

  6. High voltage conditioning • At first the electrodes don’t keep the desired high voltage • Not necessarily a problem • “Teach” the electrodes = conditioning • Increase the voltage until the current jumps • Decrease the voltage so that the current (arc) drops • Increase… • Decrease…

  7. Sparking • Sparking starts from the negative electrode (=electrons) • Pay special attention on negative electrode surface • Polish (mirror surface)

  8. Connectors/cables • High-voltage connectors • SHV • High-voltage cables • Check the specifications before use

  9. Sparking • High pressure • Free electrons in residual gas • Atmosphere, dry air: 106 V/m • Vacuum: 107 V/m • Depends on geometry (slightly)

  10. Sparking in the presence of B • Magnetic field guides electrons • B along E: no help • B perpendicular to E: helps

  11. Multipaction • Multipaction is an effect that occurs with RF fields, usually in a vacuum or low pressure condition. • Results from an ion moving back and forth (in response to an RF field) and knocking other electrons off the sides when it hits. • If the transit time of the electron is nicely synchronized with the RF field, then just as it hits, the field is right to pull the new electrons towards the other side, and a cascading avalanche can result (if the electron emission coefficient (d) is >1).

  12. Multipactoring threshold Vo = (2*p*d/l) 2 * (me*c2)/(p*e) where:Vo is the voltage between the sides of the cavityme= mass of electronl = wavelengthd = spacing between wallsc = speed of light (3x108 m/s)e = charge on an electron

  13. Remember also: • Induced high voltages at inductances (coils) • Abrupt current shut-off in a coil • High voltage capacitors in electronics • Can have HV even after power shut down

More Related