Why cosmic ray intensity needs correction with pressure?

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Discussion Overview

The discussion revolves around the need to correct cosmic ray intensity measurements based on atmospheric pressure, specifically focusing on the equation I=Io*exp(-a(Δp)). Participants seek to understand the physical implications of this correction and the underlying principles involved.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the necessity of correcting cosmic ray intensity with pressure and seeks the physical meaning behind the equation.
  • Another participant requests clarification on the context of the pressure correction, specifically which pressure is being referred to.
  • A participant clarifies that the atmospheric pressure above the neutron monitor is the relevant pressure and provides the specific equation used for correction.
  • It is proposed that higher atmospheric pressure results in more air above the detector, leading to fewer cosmic rays reaching it.
  • One participant expresses confusion regarding the implications of the correction, arguing that if pressure increases, the corrected intensity should be greater than the recorded intensity, suggesting a contradiction in the equation's application.
  • Another participant responds by indicating that the sign of the correction depends on the constant 'a' in the equation.
  • A participant attempts to clarify their previous comments, indicating that their phrasing was not intended to be rude and reflects cultural differences in communication.
  • There is a suggestion that the equation may relate to the concept of absorption in a medium, drawing parallels to a different equation involving an absorber above the detector.
  • Further clarification is provided regarding the parameters of the equation, with a participant suggesting that the notation may have been misinterpreted.

Areas of Agreement / Disagreement

Participants express differing interpretations of the pressure correction's implications, with some arguing for a specific understanding of the equation while others challenge its application. The discussion remains unresolved regarding the correct interpretation of the relationship between pressure and cosmic ray intensity.

Contextual Notes

There are unresolved assumptions regarding the definitions of parameters in the equation and the conditions under which the correction is applied. The discussion highlights potential ambiguities in the relationship between atmospheric pressure and cosmic ray measurements.

sctheorist
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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...
 
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More context would help.
A correction where, and depending on which pressure?
 
By pressure I mean the atmospheric pressure above the neutron monitor for example..The exact equation is:

I=Io*exp(-a(Pi-Pm)) 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...
 
The higher the pressure, the more material (air) is above you and the fewer cosmic rays get through.
 
Look Vanadium 50,

if the pressure is Pi>Pm then the argument in the exp is negative(a is positive) and exp(-a(Pi-Pm) 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...
 
Look, sctheorist (why so rude?) the sign of the correction depends on the sign of a.
 
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..
 
Maybe it is just the interpretation of the parameters:
sctheorist said:
By pressure I mean the atmospheric pressure above the neutron monitor for example..The exact equation is:

I=Io*exp(-a(Pi-Pm)) 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...
If I0 corresponds to Pm (I think this should be P0) and I corresponds to Pi and a is positive:
Pi-Pm>0 (more pressure at i) corresponds to I<I0 (lower neutron flux at i).
 

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