Calibration of DCD on I07
Example: X-ray Calibrating Q dependanced of Dual Crystal deflector Transmission (DCD Transmission) for liquid surfaces.
What is being calibrated and why?
On I07 two Crystals are used to deflect the beam up from the horizontal of the source then down onto the liquid surface. These crystals have some Q-dependance that varies over time due to varibales such as incident X-ray energy and temperature.
How is the calibration performed and why?
Sample is a photo diode positioned after the second crystal.
Claibration is performed by putting a diode into tht beam after the second crystal.
This is used to measure the incident flux as a function of Q.
Q is obtained by changing the angles of the crystals in such a manner as if you were measuring a liquid surface.
You must measure a range greater than the intedned Q range of the sample measurement because if you have not you won’t beable to deal with edge effects at the front and back fo the Q dependances?
When normalising the data you usually interprolate this line so you have to measure at a very high frequency greater than you would measure the sample with.
Andrew McCluskey https://islatu.readthedocs.io/en/latest/liquid_surface.html