- #1
Soilwork
- 102
- 0
I'm not to sure how to do this question.
Q. A 4MBq gamma source emitting 5 KeV photons is held at a distance of 5 cm from the end window of a detector. The diameter of the detector window is 3.5 cm, and the quantum detection efficiency of the detector is 15%.
i)What is the geometric efficiency of the setup?
ii) What fraction of the source activity is recorded by the detector?
Well I dont' particularly have a clue about the first part. I know that if it is point source you can neglect the term
y(gamma)= (radius of source)^2/(distance to detector)^2
But the question doesn't say if it is a point source or not.
If it isn't then I don't really know because you don't have the radius of the source.
Obviously I will have to use all the information given and I just can't see how to use it all.
I'm sorry I'm not too good at this stuff, but I'm trying to study for my exams in a couple of weeks and would appreciate any help :)
Q. A 4MBq gamma source emitting 5 KeV photons is held at a distance of 5 cm from the end window of a detector. The diameter of the detector window is 3.5 cm, and the quantum detection efficiency of the detector is 15%.
i)What is the geometric efficiency of the setup?
ii) What fraction of the source activity is recorded by the detector?
Well I dont' particularly have a clue about the first part. I know that if it is point source you can neglect the term
y(gamma)= (radius of source)^2/(distance to detector)^2
But the question doesn't say if it is a point source or not.
If it isn't then I don't really know because you don't have the radius of the source.
Obviously I will have to use all the information given and I just can't see how to use it all.
I'm sorry I'm not too good at this stuff, but I'm trying to study for my exams in a couple of weeks and would appreciate any help :)