Explain+XRF

BB's 2009 Fall Milestone Map



Explain theory behind XRF

 XRF stands for X-Ray Fluorescence. The purpose for using XRF is for elemental analysis. The basic theory behind the XRF lab is that a sample can be excited with X-rays. Then within the sample the excited atoms will give off their signature x-rays that are unique to their element. When an atom is exposed to x-rays, ionization of the atom occurs. Ionization consists of the ejection of an electron. If the x-ray has enough energy it will eject an electron from an inner shell. An electron from a higher shell will then jump down to the lower shell. This releases energy in the form of x-rays. Those can then be detected and put into spectrum with the magnitude of energy on the x-axis and the number of detections on the y-axis.



Explain XRF setup

The XRF has four pieces to it. There is an x-ray tube that emits x-rays onto the sample. There is a detector. The detector detects the x-rays emitted from the sample. There is also a cooler for the detector. The cooler helps the detector to be more precise and less susceptible to noise from other sources of radiation in the room.



Explain how to run XRF

The first thing to do before running the XRF lab is to set it up. Everything is usually already hooked up for the XRF lab, but the machine and computer needs to be turned on. The x-ray source also needs to be put in the tube. The sample then needs to be underneath the detector. After that the x-ray tube needs to be facing the sample and the sample needs to be underneath the detector. Once XRF is setup you turn on the software that collects the data on the computer for a set amount of time. After that you should have your data to be analyzed.

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