Physics307L:People/DePaula/Notebook/070926

Goal

Provide a measurable display of particle/wave duality of the electron. Will will attempt these measurements by creating a beam of electrons that will diffract off of a thin graphite film and create a diffraction pattern on a luminescent screen. Another option is to use magic spells to create Level 2 particle/wave duality, and summon unicorns. Because I am a level 3 rogue and cannot summon unicorns, only lesser wildabeasts, we will use the former process.^{SJK 00:38, 20 October 2007 (CDT)}

00:38, 20 October 2007 (CDT)
You should cite Anne's notebook if she was able to use magic spells.

Setup

^{SJK 00:40, 20 October 2007 (CDT)}

00:40, 20 October 2007 (CDT)
I think the explanation of the bias voltage in your summary is probably more correct. The bias voltage is too low, I think, to have an effect on the electrons leaving the filament.

We used the diagram provided to hook up the heater and a bias voltage to the electron gun. We require a bias voltage because the heater we are using does not provide enough energy. The bias voltage adds an underlying power level that the heater then builds upon. We turned on the heater and waited a couple minutes for the cathode to heat up, then we slowly raised the high voltage meter until green light appeared on the luminescent screen. We then turned on the bias voltage. After a few painful shocks we were able to adjust the bias voltage until there were two concentric green circles appearing on the luminescent screen. The bias voltage is set at 8 volts. The electron gun works by passing current through a conductive filiment creating heat and electrons which are pulled away from the cathode cylinder by the anode. The anode has a potential running through it that pulls electrons in a beam, out of the cathode and through the graphite target.

Data Collection

^{SJK 00:41, 20 October 2007 (CDT)}

00:41, 20 October 2007 (CDT)

Starting with the Hight Voltage [HV] at 5kV we measure the difference between the two radii of the concentric green rings.

Trial #	HV in kV	Outer Diameter of Inner Ring	Inner Diameter of Inner Ring	Outer Diameter of Outer Ring	Inner Diameter of Outer Ring
1	5.0 +/- 0.02	24.45mm	20.15 mm	39.51mm	36.48mm
2	4.8 +/- 0.02	24.8mm	20.49mm	42.37mm	38.41mm
3	4.6 +/- 0.02	25.47mm	21.22mm	43.32mm	38.58mm
4	4.4 +/- 0.02	26.45mm	21.32mm	45.17mm	38.54mm
5	4.2 +/- 0.02	27.58mm	22.75mm	45.32mm	40.49mm
6	4.0 +/- 0.02	28.29mm	23.03mm		41.33mm
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