Lab 12: Bragg Crystal Diffraction Flashcards
What was the objective of this lab?
to investigate a simulated crystal using microwaves, and to determine the ATOMIC SPACING using BRAGGS LAW
Why are microwaves good for the quantitative investigation of the optical properties of electromagnetic radiation?
because microwave radiation is monochromatic, plane polarized and coherent.
Instead of a crystal, what was used in this experiment to mimic it?
a foam cubic lattice of aluminum spheres spread 4 cm apart. It was transparent to radiation of approximately 3cm wavelength
components of the receiver
microammeter, crystal detector, potentiometer gain control, horn antenna
T/f The angles of reflection are the same as the angles of incidence
True
Conditions that must be present to see X ray diffraction effects
1) no matter what the value of the incident angle, each individual plane acts as a plane mirror. The angles of reflection for the waves equal the angles on incident
2) when a beam of radiation strikes a family of parallel planes, each plane will reflect part of the energy
Braggs law governs the ____ of waves from ____ planes in the lattice
Braggs law governs the DIFFRACTION of waves from PARALLEL planes in the lattice
How can one destructive interference be detected in our apparatus?
when there is no resulting detectable reflected beam in the receiver
the distance between the steel balls of our “crystal” is the :
inter-atomic spacing.
for the 110 family, how many peaks are expected to be seen in the relative intensity vs. degree graph
n=1
Possible sources of error
- the crystal was not lined up entirely.
What was the transmitter connected to?
a klystrom tube
