What is the significance of measuring attenuation in gamma rays?

[m-i-t-o]

Hello everybody, actually yesterday i read about an experiment "ATTENUATION OF GAMMA RAYS". can anybody tell me what is meanning of word ATTENUATION.And why we are measuring it? i.e. what is the sigificance of measuring it?

 

[malawi_glenn]

Try google 'ATTENUATION' first and se what you get.