Difference between revisions of "User:Jared A. Booth/Notebook/Physics 307L/2009/10/12"

From OpenWetWare
Jump to: navigation, search
Line 10: Line 10:
1) To demonstrate the wave properties of electrons.<br>
1) To demonstrate the wave properties of electrons.<br>
2) Examine the DeBroglie relation <math>\lambda = \frac {h}{p}</math><br>
2) Examine the de Broglie relation <math>\lambda = \frac {h}{p}</math><br>
3) To measure the diffraction planes of graphite.<br>
3) To measure the diffraction planes of graphite.<br>

Revision as of 17:41, 25 October 2009

Owwnotebook icon.png Project name <html><img src="/images/9/94/Report.png" border="0" /></html> Main project page
<html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>Previous entry<html>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</html>Next entry<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html>

Electron Diffraction


1) To demonstrate the wave properties of electrons.
2) Examine the de Broglie relation Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle \lambda = \frac {h}{p}}
3) To measure the diffraction planes of graphite.


 In 1924, Lois DeBroglie proposed that as photons can be seen as both waves and particles, so too can electrons.
Specifically, he postulated that the wavelength of ALL particles was related to their respective momenta by what is
now known as the DeBroglie relation.


  • Tel 2501 Universal stand
  • Electron Diffractor 2555 (5Kv .3mA)
  • Teltron Limited London England 813 KV Power Unit
  • HP 6216B Power Supply
  • Wavetek Meterman 85XT multimeter
  • Carrera Precision 6" digital caliper alloy. Note: the digital caliper's battery was low, so it was used as a standard caliper instead.


  1. The main safety concern during this procedure is electrical shock as high voltages(813KeV power supply) will be used. Standard high voltage safety precautions should be taken, including checking all equipment for damage and ensuring the equipment is properly connected.
  2. The second concern is the integrity of the equipment. Most importantly, the graphite diffraction tube. As indicated in the lab manual, the graphite is extremely thin and can be easily punctured by current overload. Use the multimeter to ensure the current stays below the maximum allowed current (0.25mA). Additionally, check the target regularly during the experiment for a red glow, indicative of current overload.


The procedure should be followed from the Lab Manual experiment 3, electron diffraction.

The following circuit was set up, with the following modification: The low voltage bias was inverted; a multimeter was put in series between the positive HV source and plug G7 on the mount to measure current. NOTE: the max voltage measurable by the multimeter is 1000V. It is important to only measure current with the multimeter while it is connected to prevent damage to the instrument as up to 5kV will be used in this experiment.
Image taken from here

Raw Data

Voltage (kV) Inner Radius (mm) Inner Diameter (mm) Outer Radius (mm) Outer Diameter (mm)
4.8 n/a 22.5 n/a 41.75
4.77 12.5 n/a 20.0 n/a
4.70 12.0 22.75 20.5 41.5
4.60 12.5 23.5 21.5 42.1
4.50 13.0 23.75 21.75 42.5
4.40 12.75 25.0 21.25 42.5
4.30 12.25 24.0 21.1 43.0
4.20 12.5 25.25 21.5 42.5
4.10 12.75 24.7 21.25 43.1
4.00 14.2 24.3 23.25 44.5
3.75 13.0 25.75 23.5 46.0
3.50 14.0 27.0 23.0 48.5
3.25 14.0 27.7 24.0 51.1
3.00 14.5 28.5 25.0 53.1
2.75 15.0 31.8 25.5 54.25
2.50 n/a n/a n/a n/a