# Pound–Rebka experiment

Im trying to understand the pound- rebka test , so was the gamma ray detector moving
, when the photon gets shot from the top of the 4th floor of the science building at harvard
to the bottom it will be blue shifted , so would they want to move the detector away at a certain speed so the doppler effect will cancel out the blueshift , and the speed that the detector is moving then using the doppler effect equation we could calculate the shift.
Any input will be much appreciated.

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Yes, I think you're on the right track although it's hard to follow what you've written. This Wiki entry might explain ( if you have not seen it already ). The experimenters certainly moved the receiver to offset the gravitational frequency shift with a Doppler shift.

http://en.wikipedia.org/wiki/Pound–Rebka_experiment

Im trying to understand the pound- rebka test , so was the gamma ray detector moving
, when the photon gets shot from the top of the 4th floor of the science building at harvard
to the bottom it will be blue shifted , so would they want to move the detector away at a certain speed so the doppler effect will cancel out the blueshift , and the speed that the detector is moving then using the doppler effect equation we could calculate the shift.
Any input will be much appreciated.
The reason is that once you move the detector at the right speed, the experimenters managed to cancel out the gravitational blueshift through the relativistic Doppler redshift. The idea was that the Doppler redshift was used as an easy to measure effect (through measuring the elevator speed "v").

ok so the detector was moving towards the earth in an elevator with a speed V .
And i am just wondering could we use the zee man effect to measure the shift ,
could we use an atom that had a specific wavelength of a photon between the ground state and some other state , that could be absorbed from the emitter but could not be absorbed at the detector because of the red shift , but if we placed the atom's in a magnetic field at the detector and had the strength of the B field tuned precisely to accept the shifted photon , would this work.

ok so the detector was moving towards the earth in an elevator with a speed V .
And i am just wondering could we use the zee man effect to measure the shift ,
could we use an atom that had a specific wavelength of a photon between the ground state and some other state , that could be absorbed from the emitter but could not be absorbed at the detector because of the red shift , but if we placed the atom's in a magnetic field at the detector and had the strength of the B field tuned precisely to accept the shifted photon , would this work.
yes, should work

sweet thanks for your response .