Physics307L F08:People/DePaula/Notebook/070919

Speed of Light Part 2

Anne Ozaksut and I worked on this lab together and we took notes primarily in her notebook, here is a link to that page F08:People/Ozaksut/Notebook/070912 Speed of Light Data

Basic Summary

We begin the experiment completely lost and confused as to the usefulness and purpose of the Time to Analog Converter [TAC]. After understanding that the entire process could be reduced to creating a curve that represents the time delay between the light emission of the LED and the light absorption of the Photo-Multiplier Tube [PMT], we finally made the first real progress. We discovered that the Time Delay box was creating tons of unnecessary interference with our data, so we removed it completely from the setup. We were also receiving a large amount of reflection in our start and stop signal, so we added 50 ohm resistors at the end of the BNC cables to dampen the residual interference. Terminating the Start/Stop signals and removing the delay box gave us a very clear and crisp signal out of the TAC. After collecting data, by measuring the voltage difference displayed by the TAC, we determined a Speed of Light around 2.6 E9. Once I speak with Dr. Koch about importing the excel file used I will go into a more detailed explanation.