Photo detector Circuitry and Hardware Relating to PARCS Rachelle Baker Mentor: Alex Cronin Department of Physics University of Arizona

NASA PARCs Primary Atomic Reference Clock in Space The purpose of the PARCS project is to place an advanced laser-cooled cesium atomic clock in orbit. It will:  test certain aspects of relativity  study performance of GPS clocks  study dynamics of atoms in microgravity

2S 1/2 2P 1/2 2P 3/2 “D1 line f = GHz “D2 line” f = GHz 10 GHz Li Energy Levels More accurate measurements of energy level transitions Specific energy level transitions correspond to a specific frequency

External Cavity Diode Laser Li Atom Beam Lithium Vapor Detector 1 Detector 2 DAQ Laser Frequency Control Electronics What did I do?

Data obtained with photo detectors

Photo detectors Photo detectors collect light from lasers by the photo-electric effect and send that to an oscilloscope to be viewed as a digital signal

High Voltage Controller  Amplifies input voltage  Needed to control laser frequency

Conclusion  Atomic physics  Optics Electronics Laser science Built parts for experiments that more accurately measured energy level transitions in Li These transitions are the basis for cesium cooled atomic clocks

Special Thanks  Dr. Alex Cronin  Ben McMorran  Tory Carr  Yancey Sechrest  Brian Anderson