why cosmic ray intensity needs correction with pressure?by sctheorist Tags: correction, cosmic, intensity, pressure 

#1
Nov2512, 01:02 PM

P: 4

Hi guys,
I cannot understand why we need to correct cosray intensity with pressure and why the equation that describes the phenomenon is I=Io*exp(a(Δp))? I want to know the phsyical meaning of this(i assume,experimental) result... Thank you... 



#2
Nov2512, 02:17 PM

Mentor
P: 10,798

More context would help.
A correction where, and depending on which pressure? 



#3
Nov2512, 02:44 PM

P: 4

By pressure I mean the atmospheric pressure above the neutron monitor for example..The exact equation is:
I=Io*exp(a(PiPm)) where: I=corrected with pressure intensity of cosray Io=the intensity recorded by the neutron monitor a= constant(namely the pressure coefficient) Pi=the atm. pressure at the time of measurment Po=the mean value of pressure in a particular amplitude where the measurment is taken thanks... 



#4
Nov2512, 03:59 PM

Mentor
P: 15,576

why cosmic ray intensity needs correction with pressure?
The higher the pressure, the more material (air) is above you and the fewer cosmic rays get through.




#5
Nov2512, 06:11 PM

P: 4

Look Vanadium 50,
if the pressure is Pi>Pm then the argument in the exp is negative(a is positive) and exp(a(PiPm) is less than 1.So the corrected value I is less than the recorded Io,which doesn't make sense. In high pressure you supposed to record a value i.e. Io=40 and the correction should be I>Io because high pressure prevents you to count all events available,right?That's a contadiction if I am not wrong... 



#6
Nov2512, 07:34 PM

Mentor
P: 15,576

Look, sctheorist (why so rude?) the sign of the correction depends on the sign of a.




#7
Nov2612, 10:55 AM

P: 4

No no you misunderstood my friend...I used "look"' in a friendly manner..Maybe it's because I'm not american..Seriously I didn't mean to offend you or something..In my language this phrase has a different meaning..Anyway...
I had a thought today about that..Maybe it has something to do with the equation I=Io*exp(μχ) that refers to an absorber above your detector. χ being the length of the path within the absorber that the particle crosses.. 



#8
Nov2612, 11:01 AM

Mentor
P: 10,798

Maybe it is just the interpretation of the parameters:
P_{i}P_{m}>0 (more pressure at i) corresponds to I<I_{0} (lower neutron flux at i). 


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