XRF

Question 0

As XRF is non destructive and portable it is Ideal for analysing….

Answer 0

Art and archeological artefacts.

Question 1

Complements to….

Answer 1

Raman spectroscopy.

Question 2

In EDS, the sample is irradiated with electrons, whereas in XRF the sample is irradiated with…..

Answer 2

A beam of X-rays

Question 3

XRF is not useful for lighter elements, H, He, Li because….

Answer 3

They only have one shell, so don’t have electron transitions.

Question 4

If an electron falls from a higher shell to a lower shell, the transition is referred to by the shell being filled.
If m1 falls to K it is a…..

Answer 4

K transition

Question 5

A disadvantage of XRF over Raman is the beam is larger, meaning it….

Answer 5

Provides less detailed info about pigment distribution.

Question 6

XRF can be fitted with a camera to allow….

Answer 6

The sample area to be well defined.

Question 7

The energy of the peaks tells us….

Answer 7

Which elements are present.

Question 8

The intensity of peaks can be compared with known standards to….

Answer 8

Find the quantity of element.

Question 9

How are secondary X-rays formed?

Answer 9

Formed from a release of energy as an electron falls from a higher to lower shell.

Question 10

The secondary X-rays result in….

Answer 10

Fluorescent radiation.

Question 11

Each elements atoms have a characteristic fluorescence emission signal, used to….

Answer 11

Obtain info about major and trace elements within pigments.

Question 12

The incident X-rays are….

Answer 12

Primary X-rays….

Question 13

The secondary X-rays are….

Answer 13

Emitted Fluorescent X-rays.

Question 14

XRF can be used for geological samples and results can be compared to….

Answer 14

Soil reference standards.

Question 15

Three advantages of portable XRF systems…

Answer 15

Analyse many samples in a short time period.
Cost efficient method at field sites.
Over 100 samples can be analysed per day.

Question 16

XRF is an example of WDS because….

Answer 16

Only a single grating is used for each element.

Question 17

Using a single grating is a major disadvantage for determine unknown analytes. To overcome this 2 things can be done….

Answer 17

Multiple diffraction gratings can be used - simultaneous XRF Spec.

Diffraction grating can be moved to a different position relative to the sample and fluorescent X-rays, to allow f-X-rays of diff wavelengths to be separated and pass to the detector.

Question 18

The distribution of peaks on the spectrum determines….

Answer 18

The presence of certain elements.

Question 19

The intensity of each element is recorded and related to…

Answer 19

The amount of each element in the sample to determine composition.

Question 20

Fluorescent X-rays are collimating into a beam, which passes through a….

Answer 20

Diffraction grating, which separates X-rays by their wavelength. X-rays of single wavelength pass to the detector.